basic frontend

2025-10-03 11:32:59 +03:00
parent 78122bc996
commit 324e861218
35 changed files with 20764 additions and 22 deletions
--- a/.gitignore
+++ b/.gitignore
@@ -17,13 +17,31 @@
 # Go workspace file
 go.work

-# IDE files
+# Environment variables
+.env
+.env.local
+.env.development.local
+.env.test.local
+.env.production.local
+
+# Node.js
+node_modules/
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+
+# React build
+frontend/build/
+frontend/dist/
+
+# IDE
 .vscode/
 .idea/
 *.swp
 *.swo
+*~

-# OS generated files
+# OS
 .DS_Store
 .DS_Store?
 ._*
@@ -31,3 +49,59 @@ go.work
 .Trashes
 ehthumbs.db
 Thumbs.db
+
+# Logs
+logs
+*.log
+
+# Runtime data
+pids
+*.pid
+*.seed
+*.pid.lock
+
+# Coverage directory used by tools like istanbul
+coverage/
+
+# nyc test coverage
+.nyc_output
+
+# Dependency directories
+jspm_packages/
+
+# Optional npm cache directory
+.npm
+
+# Optional REPL history
+.node_repl_history
+
+# Output of 'npm pack'
+*.tgz
+
+# Yarn Integrity file
+.yarn-integrity
+
+# parcel-bundler cache (https://parceljs.org/)
+.cache
+.parcel-cache
+
+# next.js build output
+.next
+
+# nuxt.js build output
+.nuxt
+
+# vuepress build output
+.vuepress/dist
+
+# Serverless directories
+.serverless
+
+# FuseBox cache
+.fusebox/
+
+# DynamoDB Local files
+.dynamodb/
+
+# TernJS port file
+.tern-port
--- a/30
+++ b/30
@@ -1,5 +1,5 @@
-# Build stage
-FROM golang:1.21-alpine AS builder
+# Build stage for Go backend
+FROM golang:1.21-alpine AS go-builder

 WORKDIR /app

@@ -10,11 +10,28 @@ COPY go.mod go.sum ./
 RUN go mod download

 # Copy source code
-COPY . .
+COPY *.go ./

 # Build the application
 RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o main .

+# Build stage for React frontend
+FROM node:18-alpine AS frontend-builder
+
+WORKDIR /app/frontend
+
+# Copy package files
+COPY frontend/package*.json ./
+
+# Install dependencies
+RUN npm ci --only=production
+
+# Copy source code
+COPY frontend/ ./
+
+# Build the React app
+RUN npm run build
+
 # Final stage
 FROM alpine:latest

@@ -23,8 +40,11 @@ RUN apk --no-cache add ca-certificates

 WORKDIR /root/

-# Copy the binary from builder stage
-COPY --from=builder /app/main .
+# Copy the Go binary from go-builder stage
+COPY --from=go-builder /app/main .
+
+# Copy the React build from frontend-builder stage
+COPY --from=frontend-builder /app/frontend/build ./frontend/build

 # Expose port
 EXPOSE 8080
--- a/README.md
+++ b/README.md
@@ -0,0 +1,230 @@
+# Counter - Habit Tracking Application
+
+A full-stack web application for tracking habits and activities with counters. Users can create counters, increment/decrement them, and view statistics. The app supports both authenticated users (with database persistence) and anonymous users (with local storage).
+
+## Features
+
+- **User Authentication**: Register and login with JWT tokens
+- **Anonymous Usage**: Work without registration using browser local storage
+- **Counter Management**: Create, edit, delete, and manage counters
+- **Increment/Decrement**: Track positive and negative changes
+- **Date-based Tracking**: Counters store entries grouped by dates
+- **Statistics**: View today, week, month, and total values
+- **Search & Filter**: Find counters by name or description
+- **Responsive Design**: Modern UI that works on all devices
+
+## Tech Stack
+
+- **Backend**: Go with Gin framework
+- **Frontend**: React with TypeScript
+- **Database**: PostgreSQL
+- **Authentication**: JWT tokens
+- **Deployment**: Docker with multi-stage builds
+
+## Quick Start
+
+### Prerequisites
+
+- Docker and Docker Compose
+- Go 1.21+ (for local development)
+- Node.js 18+ (for local development)
+
+### Using Docker Compose (Recommended)
+
+1. Clone the repository:
+```bash
+git clone <repository-url>
+cd counter
+```
+
+2. Start the application:
+```bash
+docker-compose up --build
+```
+
+3. Open your browser and navigate to `http://localhost:8080`
+
+The application will automatically:
+- Start PostgreSQL database
+- Build and run the Go backend
+- Build and serve the React frontend
+- Create necessary database tables
+
+### Local Development
+
+#### Backend Setup
+
+1. Install dependencies:
+```bash
+go mod download
+```
+
+2. Start PostgreSQL (using Docker):
+```bash
+docker run --name counter-postgres -e POSTGRES_DB=counter_db -e POSTGRES_USER=postgres -e POSTGRES_PASSWORD=password -p 5432:5432 -d postgres:15-alpine
+```
+
+3. Set environment variables:
+```bash
+export DATABASE_URL="postgres://postgres:password@localhost:5432/counter_db?sslmode=disable"
+export JWT_SECRET="your-secret-key"
+```
+
+4. Run the backend:
+```bash
+go run .
+```
+
+#### Frontend Setup
+
+1. Navigate to frontend directory:
+```bash
+cd frontend
+```
+
+2. Install dependencies:
+```bash
+npm install
+```
+
+3. Start the development server:
+```bash
+npm start
+```
+
+4. Open `http://localhost:3000` in your browser
+
+## API Endpoints
+
+### Authentication
+- `POST /api/v1/auth/register` - Register a new user
+- `POST /api/v1/auth/login` - Login user
+- `GET /api/v1/auth/me` - Get current user (protected)
+
+### Counters (Protected)
+- `GET /api/v1/counters` - Get all counters
+- `POST /api/v1/counters` - Create a new counter
+- `GET /api/v1/counters/:id` - Get specific counter
+- `PUT /api/v1/counters/:id` - Update counter
+- `DELETE /api/v1/counters/:id` - Delete counter
+- `POST /api/v1/counters/:id/increment` - Increment/decrement counter
+- `GET /api/v1/counters/:id/entries` - Get counter entries
+- `GET /api/v1/counters/:id/stats` - Get counter statistics
+
+## Database Schema
+
+### Users Table
+- `id` (SERIAL PRIMARY KEY)
+- `username` (VARCHAR(50) UNIQUE)
+- `email` (VARCHAR(255) UNIQUE)
+- `password` (VARCHAR(255))
+- `created_at` (TIMESTAMP)
+- `updated_at` (TIMESTAMP)
+
+### Counters Table
+- `id` (SERIAL PRIMARY KEY)
+- `user_id` (INTEGER REFERENCES users(id))
+- `name` (VARCHAR(100))
+- `description` (TEXT)
+- `created_at` (TIMESTAMP)
+- `updated_at` (TIMESTAMP)
+
+### Counter Entries Table
+- `id` (SERIAL PRIMARY KEY)
+- `counter_id` (INTEGER REFERENCES counters(id))
+- `value` (INTEGER)
+- `date` (DATE)
+- `created_at` (TIMESTAMP)
+
+## Anonymous User Support
+
+Anonymous users can use the application without registration:
+- Counters are stored in browser's localStorage
+- Data persists across browser sessions
+- No server-side storage for anonymous users
+- Seamless transition to authenticated user (data remains in localStorage)
+
+## Environment Variables
+
+Create a `.env` file based on `env.example`:
+
+```bash
+# Database Configuration
+DATABASE_URL=postgres://postgres:password@localhost:5432/counter_db?sslmode=disable
+
+# JWT Configuration
+JWT_SECRET=your-super-secret-jwt-key-change-in-production
+
+# Server Configuration
+PORT=8080
+GIN_MODE=release
+```
+
+## Deployment
+
+### Production Deployment
+
+1. Set environment variables for production
+2. Use a production PostgreSQL database
+3. Set a strong JWT secret
+4. Build and deploy using Docker:
+
+```bash
+docker build -t counter-app .
+docker run -p 8080:8080 \
+  -e DATABASE_URL="your-production-db-url" \
+  -e JWT_SECRET="your-production-secret" \
+  counter-app
+```
+
+### Docker Compose Production
+
+Update `docker-compose.yml` with production settings:
+- Use external PostgreSQL database
+- Set production environment variables
+- Configure proper networking and volumes
+
+## Development
+
+### Project Structure
+
+```
+counter/
+├── main.go                 # Main application entry point
+├── models.go              # Data models and DTOs
+├── database.go            # Database connection and setup
+├── auth.go                # Authentication handlers and middleware
+├── counters.go            # Counter management handlers
+├── docker-compose.yml     # Local development setup
+├── Dockerfile            # Multi-stage build for production
+├── go.mod                # Go dependencies
+├── go.sum                # Go dependencies checksum
+└── frontend/             # React frontend
+    ├── src/
+    │   ├── components/   # React components
+    │   ├── hooks/        # Custom React hooks
+    │   ├── services/     # API and localStorage services
+    │   ├── types/        # TypeScript type definitions
+    │   └── App.tsx       # Main React component
+    ├── package.json      # Node.js dependencies
+    └── public/           # Static assets
+```
+
+### Adding New Features
+
+1. **Backend**: Add new handlers in appropriate files
+2. **Frontend**: Create components in `src/components/`
+3. **API Integration**: Update services in `src/services/`
+4. **Types**: Add TypeScript interfaces in `src/types/`
+
+## Contributing
+
+1. Fork the repository
+2. Create a feature branch
+3. Make your changes
+4. Add tests if applicable
+5. Submit a pull request
+
+## License
+
+This project is licensed under the MIT License.
--- a/auth.go
+++ b/auth.go
@@ -0,0 +1,225 @@
+package main
+
+import (
+	"crypto/rand"
+	"database/sql"
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/gin-gonic/gin"
+	"github.com/golang-jwt/jwt/v5"
+	"golang.org/x/crypto/bcrypt"
+)
+
+var jwtSecret []byte
+
+// InitJWT initializes JWT secret
+func InitJWT() {
+	secret := os.Getenv("JWT_SECRET")
+	if secret == "" {
+		// Generate a random secret for development
+		secret = generateRandomSecret()
+		log.Println("Warning: Using generated JWT secret. Set JWT_SECRET environment variable for production.")
+	}
+	jwtSecret = []byte(secret)
+}
+
+// generateRandomSecret generates a random secret for JWT
+func generateRandomSecret() string {
+	b := make([]byte, 32)
+	rand.Read(b)
+	return fmt.Sprintf("%x", b)
+}
+
+// hashPassword hashes a password using bcrypt
+func hashPassword(password string) (string, error) {
+	bytes, err := bcrypt.GenerateFromPassword([]byte(password), 14)
+	return string(bytes), err
+}
+
+// checkPasswordHash compares a password with its hash
+func checkPasswordHash(password, hash string) bool {
+	err := bcrypt.CompareHashAndPassword([]byte(hash), []byte(password))
+	return err == nil
+}
+
+// generateToken generates a JWT token for a user
+func generateToken(userID int, username string) (string, error) {
+	claims := jwt.MapClaims{
+		"user_id":  userID,
+		"username": username,
+		"exp":      time.Now().Add(time.Hour * 24 * 7).Unix(), // 7 days
+		"iat":      time.Now().Unix(),
+	}
+
+	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
+	return token.SignedString(jwtSecret)
+}
+
+// validateToken validates a JWT token and returns the claims
+func validateToken(tokenString string) (jwt.MapClaims, error) {
+	token, err := jwt.Parse(tokenString, func(token *jwt.Token) (interface{}, error) {
+		if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
+			return nil, fmt.Errorf("unexpected signing method: %v", token.Header["alg"])
+		}
+		return jwtSecret, nil
+	})
+
+	if err != nil {
+		return nil, err
+	}
+
+	if claims, ok := token.Claims.(jwt.MapClaims); ok && token.Valid {
+		return claims, nil
+	}
+
+	return nil, fmt.Errorf("invalid token")
+}
+
+// AuthMiddleware validates JWT token and sets user context
+func AuthMiddleware() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		authHeader := c.GetHeader("Authorization")
+		if authHeader == "" {
+			c.JSON(http.StatusUnauthorized, gin.H{"error": "Authorization header required"})
+			c.Abort()
+			return
+		}
+
+		// Extract token from "Bearer <token>"
+		tokenParts := strings.Split(authHeader, " ")
+		if len(tokenParts) != 2 || tokenParts[0] != "Bearer" {
+			c.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid authorization header format"})
+			c.Abort()
+			return
+		}
+
+		tokenString := tokenParts[1]
+		claims, err := validateToken(tokenString)
+		if err != nil {
+			c.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid token"})
+			c.Abort()
+			return
+		}
+
+		// Set user information in context
+		c.Set("user_id", int(claims["user_id"].(float64)))
+		c.Set("username", claims["username"])
+		c.Next()
+	}
+}
+
+// RegisterHandler handles user registration
+func RegisterHandler(c *gin.Context) {
+	var req RegisterRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	// Check if username already exists
+	var existingUser User
+	err := db.QueryRow("SELECT id FROM users WHERE username = $1 OR email = $2", req.Username, req.Email).Scan(&existingUser.ID)
+	if err != sql.ErrNoRows {
+		c.JSON(http.StatusConflict, gin.H{"error": "Username or email already exists"})
+		return
+	}
+
+	// Hash password
+	hashedPassword, err := hashPassword(req.Password)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to hash password"})
+		return
+	}
+
+	// Create user
+	var user User
+	err = db.QueryRow(
+		"INSERT INTO users (username, email, password) VALUES ($1, $2, $3) RETURNING id, username, email, created_at, updated_at",
+		req.Username, req.Email, hashedPassword,
+	).Scan(&user.ID, &user.Username, &user.Email, &user.CreatedAt, &user.UpdatedAt)
+
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to create user"})
+		return
+	}
+
+	// Generate token
+	token, err := generateToken(user.ID, user.Username)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to generate token"})
+		return
+	}
+
+	c.JSON(http.StatusCreated, AuthResponse{
+		Token: token,
+		User:  user,
+	})
+}
+
+// LoginHandler handles user login
+func LoginHandler(c *gin.Context) {
+	var req LoginRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	// Find user
+	var user User
+	err := db.QueryRow(
+		"SELECT id, username, email, password, created_at, updated_at FROM users WHERE username = $1",
+		req.Username,
+	).Scan(&user.ID, &user.Username, &user.Email, &user.Password, &user.CreatedAt, &user.UpdatedAt)
+
+	if err == sql.ErrNoRows {
+		c.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid credentials"})
+		return
+	} else if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Database error"})
+		return
+	}
+
+	// Check password
+	if !checkPasswordHash(req.Password, user.Password) {
+		c.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid credentials"})
+		return
+	}
+
+	// Generate token
+	token, err := generateToken(user.ID, user.Username)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to generate token"})
+		return
+	}
+
+	// Clear password from response
+	user.Password = ""
+
+	c.JSON(http.StatusOK, AuthResponse{
+		Token: token,
+		User:  user,
+	})
+}
+
+// GetCurrentUserHandler returns the current authenticated user
+func GetCurrentUserHandler(c *gin.Context) {
+	userID := c.GetInt("user_id")
+
+	var user User
+	err := db.QueryRow(
+		"SELECT id, username, email, created_at, updated_at FROM users WHERE id = $1",
+		userID,
+	).Scan(&user.ID, &user.Username, &user.Email, &user.CreatedAt, &user.UpdatedAt)
+
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to get user"})
+		return
+	}
+
+	c.JSON(http.StatusOK, user)
+}
--- a/counters.go
+++ b/counters.go
@@ -0,0 +1,356 @@
+package main
+
+import (
+	"database/sql"
+	"fmt"
+	"net/http"
+	"strconv"
+	"time"
+
+	"github.com/gin-gonic/gin"
+)
+
+// CreateCounterHandler creates a new counter
+func CreateCounterHandler(c *gin.Context) {
+	var req CreateCounterRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	userID := c.GetInt("user_id")
+
+	var counter Counter
+	err := db.QueryRow(
+		"INSERT INTO counters (user_id, name, description) VALUES ($1, $2, $3) RETURNING id, user_id, name, description, created_at, updated_at",
+		userID, req.Name, req.Description,
+	).Scan(&counter.ID, &counter.UserID, &counter.Name, &counter.Description, &counter.CreatedAt, &counter.UpdatedAt)
+
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to create counter"})
+		return
+	}
+
+	c.JSON(http.StatusCreated, counter)
+}
+
+// GetCountersHandler retrieves all counters for the authenticated user
+func GetCountersHandler(c *gin.Context) {
+	userID := c.GetInt("user_id")
+	search := c.Query("search")
+
+	query := `
+		SELECT c.id, c.user_id, c.name, c.description, c.created_at, c.updated_at,
+		       COALESCE(SUM(ce.value), 0) as total_value,
+		       COALESCE(SUM(CASE WHEN ce.date = CURRENT_DATE THEN ce.value ELSE 0 END), 0) as today_value,
+		       COALESCE(SUM(CASE WHEN ce.date >= CURRENT_DATE - INTERVAL '7 days' THEN ce.value ELSE 0 END), 0) as week_value,
+		       COALESCE(SUM(CASE WHEN ce.date >= DATE_TRUNC('month', CURRENT_DATE) THEN ce.value ELSE 0 END), 0) as month_value,
+		       COUNT(ce.id) as entry_count
+		FROM counters c
+		LEFT JOIN counter_entries ce ON c.id = ce.counter_id
+		WHERE c.user_id = $1
+	`
+
+	args := []interface{}{userID}
+	if search != "" {
+		query += " AND (c.name ILIKE $2 OR c.description ILIKE $2)"
+		args = append(args, "%"+search+"%")
+	}
+
+	query += " GROUP BY c.id, c.user_id, c.name, c.description, c.created_at, c.updated_at ORDER BY c.updated_at DESC"
+
+	rows, err := db.Query(query, args...)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to fetch counters"})
+		return
+	}
+	defer rows.Close()
+
+	var counters []CounterWithStats
+	for rows.Next() {
+		var counter CounterWithStats
+		err := rows.Scan(
+			&counter.ID, &counter.UserID, &counter.Name, &counter.Description,
+			&counter.CreatedAt, &counter.UpdatedAt, &counter.TotalValue,
+			&counter.TodayValue, &counter.WeekValue, &counter.MonthValue,
+			&counter.EntryCount,
+		)
+		if err != nil {
+			c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to scan counter"})
+			return
+		}
+		counters = append(counters, counter)
+	}
+
+	c.JSON(http.StatusOK, counters)
+}
+
+// GetCounterHandler retrieves a specific counter by ID
+func GetCounterHandler(c *gin.Context) {
+	userID := c.GetInt("user_id")
+	counterID, err := strconv.Atoi(c.Param("id"))
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid counter ID"})
+		return
+	}
+
+	var counter CounterWithStats
+	err = db.QueryRow(`
+		SELECT c.id, c.user_id, c.name, c.description, c.created_at, c.updated_at,
+		       COALESCE(SUM(ce.value), 0) as total_value,
+		       COALESCE(SUM(CASE WHEN ce.date = CURRENT_DATE THEN ce.value ELSE 0 END), 0) as today_value,
+		       COALESCE(SUM(CASE WHEN ce.date >= CURRENT_DATE - INTERVAL '7 days' THEN ce.value ELSE 0 END), 0) as week_value,
+		       COALESCE(SUM(CASE WHEN ce.date >= DATE_TRUNC('month', CURRENT_DATE) THEN ce.value ELSE 0 END), 0) as month_value,
+		       COUNT(ce.id) as entry_count
+		FROM counters c
+		LEFT JOIN counter_entries ce ON c.id = ce.counter_id
+		WHERE c.id = $1 AND c.user_id = $2
+		GROUP BY c.id, c.user_id, c.name, c.description, c.created_at, c.updated_at
+	`, counterID, userID).Scan(
+		&counter.ID, &counter.UserID, &counter.Name, &counter.Description,
+		&counter.CreatedAt, &counter.UpdatedAt, &counter.TotalValue,
+		&counter.TodayValue, &counter.WeekValue, &counter.MonthValue,
+		&counter.EntryCount,
+	)
+
+	if err == sql.ErrNoRows {
+		c.JSON(http.StatusNotFound, gin.H{"error": "Counter not found"})
+		return
+	} else if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to fetch counter"})
+		return
+	}
+
+	c.JSON(http.StatusOK, counter)
+}
+
+// UpdateCounterHandler updates a counter
+func UpdateCounterHandler(c *gin.Context) {
+	userID := c.GetInt("user_id")
+	counterID, err := strconv.Atoi(c.Param("id"))
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid counter ID"})
+		return
+	}
+
+	var req UpdateCounterRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	var counter Counter
+	err = db.QueryRow(
+		"UPDATE counters SET name = $1, description = $2, updated_at = CURRENT_TIMESTAMP WHERE id = $3 AND user_id = $4 RETURNING id, user_id, name, description, created_at, updated_at",
+		req.Name, req.Description, counterID, userID,
+	).Scan(&counter.ID, &counter.UserID, &counter.Name, &counter.Description, &counter.CreatedAt, &counter.UpdatedAt)
+
+	if err == sql.ErrNoRows {
+		c.JSON(http.StatusNotFound, gin.H{"error": "Counter not found"})
+		return
+	} else if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to update counter"})
+		return
+	}
+
+	c.JSON(http.StatusOK, counter)
+}
+
+// DeleteCounterHandler deletes a counter
+func DeleteCounterHandler(c *gin.Context) {
+	userID := c.GetInt("user_id")
+	counterID, err := strconv.Atoi(c.Param("id"))
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid counter ID"})
+		return
+	}
+
+	result, err := db.Exec("DELETE FROM counters WHERE id = $1 AND user_id = $2", counterID, userID)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to delete counter"})
+		return
+	}
+
+	rowsAffected, err := result.RowsAffected()
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to check deletion"})
+		return
+	}
+
+	if rowsAffected == 0 {
+		c.JSON(http.StatusNotFound, gin.H{"error": "Counter not found"})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{"message": "Counter deleted successfully"})
+}
+
+// IncrementCounterHandler increments/decrements a counter
+func IncrementCounterHandler(c *gin.Context) {
+	userID := c.GetInt("user_id")
+	counterID, err := strconv.Atoi(c.Param("id"))
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid counter ID"})
+		return
+	}
+
+	var req IncrementRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	// Verify counter belongs to user
+	var exists bool
+	err = db.QueryRow("SELECT EXISTS(SELECT 1 FROM counters WHERE id = $1 AND user_id = $2)", counterID, userID).Scan(&exists)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Database error"})
+		return
+	}
+	if !exists {
+		c.JSON(http.StatusNotFound, gin.H{"error": "Counter not found"})
+		return
+	}
+
+	// Insert counter entry
+	var entry CounterEntry
+	err = db.QueryRow(
+		"INSERT INTO counter_entries (counter_id, value, date) VALUES ($1, $2, CURRENT_DATE) RETURNING id, counter_id, value, date, created_at",
+		counterID, req.Value,
+	).Scan(&entry.ID, &entry.CounterID, &entry.Value, &entry.Date, &entry.CreatedAt)
+
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to create counter entry"})
+		return
+	}
+
+	// Update counter's updated_at timestamp
+	_, err = db.Exec("UPDATE counters SET updated_at = CURRENT_TIMESTAMP WHERE id = $1", counterID)
+	if err != nil {
+		// Log error but don't fail the request
+		fmt.Printf("Warning: Failed to update counter timestamp: %v\n", err)
+	}
+
+	c.JSON(http.StatusCreated, entry)
+}
+
+// GetCounterEntriesHandler retrieves entries for a specific counter
+func GetCounterEntriesHandler(c *gin.Context) {
+	userID := c.GetInt("user_id")
+	counterID, err := strconv.Atoi(c.Param("id"))
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid counter ID"})
+		return
+	}
+
+	// Verify counter belongs to user
+	var exists bool
+	err = db.QueryRow("SELECT EXISTS(SELECT 1 FROM counters WHERE id = $1 AND user_id = $2)", counterID, userID).Scan(&exists)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Database error"})
+		return
+	}
+	if !exists {
+		c.JSON(http.StatusNotFound, gin.H{"error": "Counter not found"})
+		return
+	}
+
+	// Parse date range parameters
+	startDate := c.Query("start_date")
+	endDate := c.Query("end_date")
+
+	query := `
+		SELECT id, counter_id, value, date, created_at
+		FROM counter_entries
+		WHERE counter_id = $1
+	`
+	args := []interface{}{counterID}
+
+	if startDate != "" {
+		query += " AND date >= $2"
+		args = append(args, startDate)
+		if endDate != "" {
+			query += " AND date <= $3"
+			args = append(args, endDate)
+		}
+	} else if endDate != "" {
+		query += " AND date <= $2"
+		args = append(args, endDate)
+	}
+
+	query += " ORDER BY date DESC, created_at DESC"
+
+	rows, err := db.Query(query, args...)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to fetch counter entries"})
+		return
+	}
+	defer rows.Close()
+
+	var entries []CounterEntry
+	for rows.Next() {
+		var entry CounterEntry
+		err := rows.Scan(&entry.ID, &entry.CounterID, &entry.Value, &entry.Date, &entry.CreatedAt)
+		if err != nil {
+			c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to scan entry"})
+			return
+		}
+		entries = append(entries, entry)
+	}
+
+	c.JSON(http.StatusOK, entries)
+}
+
+// GetCounterStatsHandler retrieves statistics for a counter
+func GetCounterStatsHandler(c *gin.Context) {
+	userID := c.GetInt("user_id")
+	counterID, err := strconv.Atoi(c.Param("id"))
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid counter ID"})
+		return
+	}
+
+	// Verify counter belongs to user
+	var exists bool
+	err = db.QueryRow("SELECT EXISTS(SELECT 1 FROM counters WHERE id = $1 AND user_id = $2)", counterID, userID).Scan(&exists)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Database error"})
+		return
+	}
+	if !exists {
+		c.JSON(http.StatusNotFound, gin.H{"error": "Counter not found"})
+		return
+	}
+
+	// Get daily statistics for the last 30 days
+	rows, err := db.Query(`
+		SELECT date, SUM(value) as daily_total
+		FROM counter_entries
+		WHERE counter_id = $1 AND date >= CURRENT_DATE - INTERVAL '30 days'
+		GROUP BY date
+		ORDER BY date DESC
+	`, counterID)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to fetch statistics"})
+		return
+	}
+	defer rows.Close()
+
+	type DailyStat struct {
+		Date  time.Time `json:"date"`
+		Total int       `json:"total"`
+	}
+
+	var stats []DailyStat
+	for rows.Next() {
+		var stat DailyStat
+		err := rows.Scan(&stat.Date, &stat.Total)
+		if err != nil {
+			c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to scan statistic"})
+			return
+		}
+		stats = append(stats, stat)
+	}
+
+	c.JSON(http.StatusOK, gin.H{"daily_stats": stats})
+}
--- a/database.go
+++ b/database.go
@@ -0,0 +1,82 @@
+package main
+
+import (
+	"database/sql"
+	"fmt"
+	"log"
+	"os"
+
+	_ "github.com/lib/pq"
+)
+
+var db *sql.DB
+
+// InitDB initializes the database connection
+func InitDB() error {
+	// Get database URL from environment variable
+	dbURL := os.Getenv("DATABASE_URL")
+	if dbURL == "" {
+		// Default for local development
+		dbURL = "postgres://postgres:password@localhost:5432/counter_db?sslmode=disable"
+	}
+
+	var err error
+	db, err = sql.Open("postgres", dbURL)
+	if err != nil {
+		return fmt.Errorf("failed to open database: %w", err)
+	}
+
+	// Test the connection
+	if err = db.Ping(); err != nil {
+		return fmt.Errorf("failed to ping database: %w", err)
+	}
+
+	log.Println("Database connection established")
+	return nil
+}
+
+// CreateTables creates the necessary database tables
+func CreateTables() error {
+	queries := []string{
+		`CREATE TABLE IF NOT EXISTS users (
+			id SERIAL PRIMARY KEY,
+			username VARCHAR(50) UNIQUE NOT NULL,
+			email VARCHAR(255) UNIQUE NOT NULL,
+			password VARCHAR(255) NOT NULL,
+			created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+			updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+		)`,
+		`CREATE TABLE IF NOT EXISTS counters (
+			id SERIAL PRIMARY KEY,
+			user_id INTEGER REFERENCES users(id) ON DELETE CASCADE,
+			name VARCHAR(100) NOT NULL,
+			description TEXT,
+			created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+			updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+		)`,
+		`CREATE TABLE IF NOT EXISTS counter_entries (
+			id SERIAL PRIMARY KEY,
+			counter_id INTEGER REFERENCES counters(id) ON DELETE CASCADE,
+			value INTEGER NOT NULL,
+			date DATE NOT NULL,
+			created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+		)`,
+		`CREATE INDEX IF NOT EXISTS idx_counters_user_id ON counters(user_id)`,
+		`CREATE INDEX IF NOT EXISTS idx_counter_entries_counter_id ON counter_entries(counter_id)`,
+		`CREATE INDEX IF NOT EXISTS idx_counter_entries_date ON counter_entries(date)`,
+	}
+
+	for _, query := range queries {
+		if _, err := db.Exec(query); err != nil {
+			return fmt.Errorf("failed to execute query: %w", err)
+		}
+	}
+
+	log.Println("Database tables created successfully")
+	return nil
+}
+
+// GetDB returns the database connection
+func GetDB() *sql.DB {
+	return db
+}
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -0,0 +1,33 @@
+services:
+  postgres:
+    image: postgres:15-alpine
+    environment:
+      POSTGRES_DB: counter_db
+      POSTGRES_USER: postgres
+      POSTGRES_PASSWORD: password
+    ports:
+      - "5432:5432"
+    volumes:
+      - postgres_data:/var/lib/postgresql/data
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U postgres"]
+      interval: 10s
+      timeout: 5s
+      retries: 5
+
+  app:
+    build: .
+    ports:
+      - "8080:8080"
+    environment:
+      DATABASE_URL: postgres://postgres:password@postgres:5432/counter_db?sslmode=disable
+      JWT_SECRET: your-super-secret-jwt-key-change-in-production
+      GIN_MODE: release
+    depends_on:
+      postgres:
+        condition: service_healthy
+    volumes:
+      - ./frontend/build:/app/frontend/build
+
+volumes:
+  postgres_data:
--- a/env.example
+++ b/env.example
@@ -0,0 +1,12 @@
+# Database Configuration
+DATABASE_URL=postgres://postgres:password@localhost:5432/counter_db?sslmode=disable
+
+# JWT Configuration
+JWT_SECRET=your-super-secret-jwt-key-change-in-production
+
+# Server Configuration
+PORT=8080
+GIN_MODE=release
+
+# Frontend Configuration (for development)
+REACT_APP_API_URL=http://localhost:8080/api/v1
--- a/frontend/package-lock.json
+++ b/frontend/package-lock.json
--- a/frontend/package.json
+++ b/frontend/package.json
@@ -0,0 +1,51 @@
+{
+  "name": "counter-frontend",
+  "version": "0.1.0",
+  "private": true,
+  "dependencies": {
+    "@types/node": "^16.18.0",
+    "@types/react": "^18.2.0",
+    "@types/react-dom": "^18.2.0",
+    "react": "^18.2.0",
+    "react-dom": "^18.2.0",
+    "react-router-dom": "^6.8.0",
+    "react-scripts": "5.0.1",
+    "typescript": "^4.9.0",
+    "axios": "^1.6.0",
+    "react-hook-form": "^7.48.0",
+    "react-query": "^3.39.0",
+    "date-fns": "^2.30.0",
+    "lucide-react": "^0.294.0",
+    "tailwindcss": "^3.3.0",
+    "autoprefixer": "^10.4.0",
+    "postcss": "^8.4.0"
+  },
+  "scripts": {
+    "start": "react-scripts start",
+    "build": "react-scripts build",
+    "test": "react-scripts test",
+    "eject": "react-scripts eject"
+  },
+  "eslintConfig": {
+    "extends": [
+      "react-app",
+      "react-app/jest"
+    ]
+  },
+  "browserslist": {
+    "production": [
+      ">0.2%",
+      "not dead",
+      "not op_mini all"
+    ],
+    "development": [
+      "last 1 chrome version",
+      "last 1 firefox version",
+      "last 1 safari version"
+    ]
+  },
+  "devDependencies": {
+    "@types/jest": "^27.5.0"
+  },
+  "proxy": "http://localhost:8080"
+}
--- a/frontend/postcss.config.js
+++ b/frontend/postcss.config.js
@@ -0,0 +1,6 @@
+module.exports = {
+  plugins: {
+    tailwindcss: {},
+    autoprefixer: {},
+  },
+}
--- a/frontend/public/index.html
+++ b/frontend/public/index.html
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8" />
+    <link rel="icon" href="%PUBLIC_URL%/favicon.ico" />
+    <meta name="viewport" content="width=device-width, initial-scale=1" />
+    <meta name="theme-color" content="#000000" />
+    <meta
+      name="description"
+      content="Counter - Track your habits and activities"
+    />
+    <title>Counter</title>
+  </head>
+  <body>
+    <noscript>You need to enable JavaScript to run this app.</noscript>
+    <div id="root"></div>
+  </body>
+</html>
--- a/frontend/src/App.css
+++ b/frontend/src/App.css
@@ -0,0 +1,43 @@
+@tailwind base;
+@tailwind components;
+@tailwind utilities;
+
+@layer base {
+  html {
+    font-family: 'Inter', system-ui, sans-serif;
+  }
+}
+
+@layer components {
+  .btn {
+    @apply px-4 py-2 rounded-lg font-medium transition-colors duration-200 focus:outline-none focus:ring-2 focus:ring-offset-2;
+  }
+  
+  .btn-primary {
+    @apply bg-primary-600 text-white hover:bg-primary-700 focus:ring-primary-500;
+  }
+  
+  .btn-secondary {
+    @apply bg-gray-200 text-gray-900 hover:bg-gray-300 focus:ring-gray-500;
+  }
+  
+  .btn-danger {
+    @apply bg-red-600 text-white hover:bg-red-700 focus:ring-red-500;
+  }
+  
+  .btn-success {
+    @apply bg-green-600 text-white hover:bg-green-700 focus:ring-green-500;
+  }
+  
+  .input {
+    @apply w-full px-3 py-2 border border-gray-300 rounded-lg focus:outline-none focus:ring-2 focus:ring-primary-500 focus:border-transparent;
+  }
+  
+  .card {
+    @apply bg-white rounded-lg shadow-md border border-gray-200;
+  }
+  
+  .counter-card {
+    @apply card p-6 hover:shadow-lg transition-shadow duration-200;
+  }
+}
--- a/frontend/src/App.tsx
+++ b/frontend/src/App.tsx
@@ -0,0 +1,41 @@
+import React from 'react';
+import { BrowserRouter as Router, Routes, Route, Navigate } from 'react-router-dom';
+import { AuthProvider } from './hooks/useAuth';
+import { ProtectedRoute } from './components/ProtectedRoute';
+import { Layout } from './components/Layout';
+import { Login } from './components/Login';
+import { Register } from './components/Register';
+import { Dashboard } from './components/Dashboard';
+import { CounterDetail } from './components/CounterDetail';
+import './App.css';
+
+function App() {
+  return (
+    <AuthProvider>
+      <Router>
+        <div className="App">
+          <Routes>
+            <Route path="/login" element={<Login />} />
+            <Route path="/register" element={<Register />} />
+            <Route
+              path="/*"
+              element={
+                <ProtectedRoute>
+                  <Layout>
+                    <Routes>
+                      <Route path="/" element={<Dashboard />} />
+                      <Route path="/counter/:id" element={<CounterDetail />} />
+                      <Route path="*" element={<Navigate to="/" replace />} />
+                    </Routes>
+                  </Layout>
+                </ProtectedRoute>
+              }
+            />
+          </Routes>
+        </div>
+      </Router>
+    </AuthProvider>
+  );
+}
+
+export default App;
--- a/frontend/src/components/CounterCard.tsx
+++ b/frontend/src/components/CounterCard.tsx
@@ -0,0 +1,130 @@
+import React, { useState } from 'react';
+import { Link } from 'react-router-dom';
+import { useCounters } from '../hooks/useCounters';
+import { CounterWithStats } from '../types';
+import { Plus, Minus, Edit, Trash2, MoreVertical } from 'lucide-react';
+
+interface CounterCardProps {
+  counter: CounterWithStats;
+}
+
+export const CounterCard: React.FC<CounterCardProps> = ({ counter }) => {
+  const { incrementCounter, deleteCounter } = useCounters();
+  const [isLoading, setIsLoading] = useState(false);
+  const [showMenu, setShowMenu] = useState(false);
+
+  const handleIncrement = async (value: number) => {
+    setIsLoading(true);
+    try {
+      await incrementCounter(counter.id, value);
+    } catch (error) {
+      console.error('Failed to increment counter:', error);
+    } finally {
+      setIsLoading(false);
+    }
+  };
+
+  const handleDelete = async () => {
+    if (window.confirm('Are you sure you want to delete this counter?')) {
+      try {
+        await deleteCounter(counter.id);
+      } catch (error) {
+        console.error('Failed to delete counter:', error);
+      }
+    }
+  };
+
+  return (
+    <div className="counter-card">
+      <div className="flex justify-between items-start mb-4">
+        <div className="flex-1">
+          <h3 className="text-lg font-semibold text-gray-900 mb-1">
+            {counter.name}
+          </h3>
+          {counter.description && (
+            <p className="text-sm text-gray-600 mb-2">{counter.description}</p>
+          )}
+        </div>
+        <div className="relative">
+          <button
+            onClick={() => setShowMenu(!showMenu)}
+            className="p-1 text-gray-400 hover:text-gray-600"
+          >
+            <MoreVertical className="h-5 w-5" />
+          </button>
+          {showMenu && (
+            <div className="absolute right-0 mt-2 w-48 bg-white rounded-md shadow-lg py-1 z-10 border border-gray-200">
+              <Link
+                to={`/counter/${counter.id}`}
+                className="flex items-center px-4 py-2 text-sm text-gray-700 hover:bg-gray-100"
+                onClick={() => setShowMenu(false)}
+              >
+                <Edit className="h-4 w-4 mr-2" />
+                View Details
+              </Link>
+              <button
+                onClick={() => {
+                  handleDelete();
+                  setShowMenu(false);
+                }}
+                className="flex items-center w-full px-4 py-2 text-sm text-red-600 hover:bg-gray-100"
+              >
+                <Trash2 className="h-4 w-4 mr-2" />
+                Delete
+              </button>
+            </div>
+          )}
+        </div>
+      </div>
+
+      {/* Counter Value */}
+      <div className="text-center mb-6">
+        <div className="text-4xl font-bold text-primary-600 mb-2">
+          {counter.total_value}
+        </div>
+        <div className="text-sm text-gray-500">Total</div>
+      </div>
+
+      {/* Quick Stats */}
+      <div className="grid grid-cols-3 gap-4 mb-6 text-center">
+        <div>
+          <div className="text-lg font-semibold text-gray-900">{counter.today_value}</div>
+          <div className="text-xs text-gray-500">Today</div>
+        </div>
+        <div>
+          <div className="text-lg font-semibold text-gray-900">{counter.week_value}</div>
+          <div className="text-xs text-gray-500">Week</div>
+        </div>
+        <div>
+          <div className="text-lg font-semibold text-gray-900">{counter.month_value}</div>
+          <div className="text-xs text-gray-500">Month</div>
+        </div>
+      </div>
+
+      {/* Action Buttons */}
+      <div className="flex space-x-2">
+        <button
+          onClick={() => handleIncrement(-1)}
+          disabled={isLoading}
+          className="btn btn-secondary flex-1 flex items-center justify-center disabled:opacity-50"
+        >
+          <Minus className="h-4 w-4" />
+        </button>
+        <button
+          onClick={() => handleIncrement(1)}
+          disabled={isLoading}
+          className="btn btn-primary flex-1 flex items-center justify-center disabled:opacity-50"
+        >
+          <Plus className="h-4 w-4" />
+        </button>
+      </div>
+
+      {/* Entry Count */}
+      <div className="mt-4 text-center">
+        <div className="text-xs text-gray-500">
+          {counter.entry_count} entries
+        </div>
+      </div>
+    </div>
+  );
+};
--- a/frontend/src/components/CounterDetail.tsx
+++ b/frontend/src/components/CounterDetail.tsx
@@ -0,0 +1,256 @@
+import React, { useState, useEffect } from 'react';
+import { useParams, useNavigate } from 'react-router-dom';
+import { useCounters } from '../hooks/useCounters';
+import { useAuth } from '../hooks/useAuth';
+import { CounterWithStats, CounterEntry } from '../types';
+import { countersAPI } from '../services/api';
+import { ArrowLeft, Plus, Minus, Edit, Trash2, Calendar, TrendingUp } from 'lucide-react';
+import { format } from 'date-fns';
+
+export const CounterDetail: React.FC = () => {
+  const { id } = useParams<{ id: string }>();
+  const navigate = useNavigate();
+  const { isAuthenticated } = useAuth();
+  const { incrementCounter, deleteCounter } = useCounters();
+  
+  const [counter, setCounter] = useState<CounterWithStats | null>(null);
+  const [entries, setEntries] = useState<CounterEntry[]>([]);
+  const [isLoading, setIsLoading] = useState(true);
+  const [isIncrementing, setIsIncrementing] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+
+  useEffect(() => {
+    if (id) {
+      loadCounterData();
+    }
+  }, [id]);
+
+  const loadCounterData = async () => {
+    if (!id) return;
+    
+    setIsLoading(true);
+    setError(null);
+    
+    try {
+      if (isAuthenticated) {
+        // Load from API
+        const [counterResponse, entriesResponse] = await Promise.all([
+          countersAPI.getCounter(parseInt(id)),
+          countersAPI.getCounterEntries(parseInt(id))
+        ]);
+        setCounter(counterResponse.data);
+        setEntries(entriesResponse.data);
+      } else {
+        // Load from localStorage
+        const counters = JSON.parse(localStorage.getItem('anonymous_counters') || '[]');
+        const foundCounter = counters.find((c: any) => c.id === id);
+        if (foundCounter) {
+          // Convert to CounterWithStats format
+          const today = new Date().toISOString().split('T')[0];
+          const counterWithStats: CounterWithStats = {
+            id: parseInt(foundCounter.id),
+            name: foundCounter.name,
+            description: foundCounter.description,
+            created_at: foundCounter.created_at,
+            updated_at: foundCounter.updated_at,
+            total_value: foundCounter.total_value,
+            today_value: foundCounter.entries[today] || 0,
+            week_value: Object.entries(foundCounter.entries)
+              .filter(([date]) => {
+                const entryDate = new Date(date);
+                const weekAgo = new Date();
+                weekAgo.setDate(weekAgo.getDate() - 7);
+                return entryDate >= weekAgo;
+              })
+              .reduce((sum, [, value]) => sum + (value as number), 0),
+            month_value: Object.entries(foundCounter.entries)
+              .filter(([date]) => {
+                const entryDate = new Date(date);
+                const monthAgo = new Date();
+                monthAgo.setMonth(monthAgo.getMonth() - 1);
+                return entryDate >= monthAgo;
+              })
+              .reduce((sum, [, value]) => sum + (value as number), 0),
+            entry_count: Object.values(foundCounter.entries).reduce((sum: number, value: unknown) => sum + Math.abs(value as number), 0),
+          };
+          setCounter(counterWithStats);
+          
+          // Convert entries to CounterEntry format
+          const counterEntries: CounterEntry[] = Object.entries(foundCounter.entries)
+            .map(([date, value]) => ({
+              id: Math.random(), // Generate random ID for display
+              counter_id: parseInt(foundCounter.id),
+              value: value as number,
+              date: date,
+              created_at: new Date().toISOString(),
+            }))
+            .sort((a, b) => new Date(b.date).getTime() - new Date(a.date).getTime());
+          setEntries(counterEntries);
+        } else {
+          setError('Counter not found');
+        }
+      }
+    } catch (err: any) {
+      setError(err.response?.data?.error || 'Failed to load counter');
+    } finally {
+      setIsLoading(false);
+    }
+  };
+
+  const handleIncrement = async (value: number) => {
+    if (!counter) return;
+    
+    setIsIncrementing(true);
+    try {
+      await incrementCounter(counter.id, value);
+      // Reload data to get updated values
+      await loadCounterData();
+    } catch (error) {
+      console.error('Failed to increment counter:', error);
+    } finally {
+      setIsIncrementing(false);
+    }
+  };
+
+  const handleDelete = async () => {
+    if (!counter) return;
+    
+    if (window.confirm('Are you sure you want to delete this counter?')) {
+      try {
+        await deleteCounter(counter.id);
+        navigate('/');
+      } catch (error) {
+        console.error('Failed to delete counter:', error);
+      }
+    }
+  };
+
+  if (isLoading) {
+    return (
+      <div className="flex justify-center items-center py-12">
+        <div className="animate-spin rounded-full h-12 w-12 border-b-2 border-primary-600"></div>
+      </div>
+    );
+  }
+
+  if (error || !counter) {
+    return (
+      <div className="text-center py-12">
+        <div className="text-red-600 mb-4">{error || 'Counter not found'}</div>
+        <button
+          onClick={() => navigate('/')}
+          className="btn btn-primary"
+        >
+          Back to Dashboard
+        </button>
+      </div>
+    );
+  }
+
+  return (
+    <div className="space-y-6">
+      {/* Header */}
+      <div className="flex items-center space-x-4">
+        <button
+          onClick={() => navigate('/')}
+          className="p-2 text-gray-400 hover:text-gray-600"
+        >
+          <ArrowLeft className="h-6 w-6" />
+        </button>
+        <div className="flex-1">
+          <h1 className="text-3xl font-bold text-gray-900">{counter.name}</h1>
+          {counter.description && (
+            <p className="text-gray-600 mt-1">{counter.description}</p>
+          )}
+        </div>
+        <div className="flex space-x-2">
+          <button
+            onClick={handleDelete}
+            className="btn btn-danger flex items-center space-x-2"
+          >
+            <Trash2 className="h-4 w-4" />
+            <span>Delete</span>
+          </button>
+        </div>
+      </div>
+
+      {/* Counter Value and Controls */}
+      <div className="card p-8 text-center">
+        <div className="text-6xl font-bold text-primary-600 mb-4">
+          {counter.total_value}
+        </div>
+        <div className="text-lg text-gray-600 mb-8">Total Count</div>
+        
+        <div className="flex justify-center space-x-4">
+          <button
+            onClick={() => handleIncrement(-1)}
+            disabled={isIncrementing}
+            className="btn btn-secondary text-2xl px-8 py-4 disabled:opacity-50"
+          >
+            <Minus className="h-8 w-8" />
+          </button>
+          <button
+            onClick={() => handleIncrement(1)}
+            disabled={isIncrementing}
+            className="btn btn-primary text-2xl px-8 py-4 disabled:opacity-50"
+          >
+            <Plus className="h-8 w-8" />
+          </button>
+        </div>
+      </div>
+
+      {/* Stats Grid */}
+      <div className="grid grid-cols-1 md:grid-cols-3 gap-6">
+        <div className="card p-6 text-center">
+          <div className="text-2xl font-bold text-green-600 mb-2">{counter.today_value}</div>
+          <div className="text-sm text-gray-600">Today</div>
+        </div>
+        <div className="card p-6 text-center">
+          <div className="text-2xl font-bold text-blue-600 mb-2">{counter.week_value}</div>
+          <div className="text-sm text-gray-600">This Week</div>
+        </div>
+        <div className="card p-6 text-center">
+          <div className="text-2xl font-bold text-purple-600 mb-2">{counter.month_value}</div>
+          <div className="text-sm text-gray-600">This Month</div>
+        </div>
+      </div>
+
+      {/* Recent Entries */}
+      <div className="card p-6">
+        <h2 className="text-xl font-semibold text-gray-900 mb-4 flex items-center">
+          <Calendar className="h-5 w-5 mr-2" />
+          Recent Entries
+        </h2>
+        
+        {entries.length === 0 ? (
+          <div className="text-center py-8 text-gray-500">
+            No entries yet. Start by incrementing your counter!
+          </div>
+        ) : (
+          <div className="space-y-3">
+            {entries.slice(0, 10).map((entry) => (
+              <div
+                key={entry.id}
+                className="flex justify-between items-center py-2 px-4 bg-gray-50 rounded-lg"
+              >
+                <div className="flex items-center space-x-3">
+                  <div className={`w-3 h-3 rounded-full ${
+                    entry.value > 0 ? 'bg-green-500' : 'bg-red-500'
+                  }`} />
+                  <span className="text-sm text-gray-600">
+                    {format(new Date(entry.date), 'MMM dd, yyyy')}
+                  </span>
+                </div>
+                <div className={`text-sm font-medium ${
+                  entry.value > 0 ? 'text-green-600' : 'text-red-600'
+                }`}>
+                  {entry.value > 0 ? '+' : ''}{entry.value}
+                </div>
+              </div>
+            ))}
+          </div>
+        )}
+      </div>
+    </div>
+  );
+};
--- a/frontend/src/components/CreateCounterModal.tsx
+++ b/frontend/src/components/CreateCounterModal.tsx
@@ -0,0 +1,110 @@
+import React, { useState } from 'react';
+import { useForm } from 'react-hook-form';
+import { useCounters } from '../hooks/useCounters';
+import { CreateCounterRequest } from '../types';
+import { X } from 'lucide-react';
+
+interface CreateCounterModalProps {
+  onClose: () => void;
+}
+
+export const CreateCounterModal: React.FC<CreateCounterModalProps> = ({ onClose }) => {
+  const { createCounter } = useCounters();
+  const [isLoading, setIsLoading] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+
+  const {
+    register,
+    handleSubmit,
+    formState: { errors },
+  } = useForm<CreateCounterRequest>();
+
+  const onSubmit = async (data: CreateCounterRequest) => {
+    setIsLoading(true);
+    setError(null);
+    try {
+      await createCounter(data);
+      onClose();
+    } catch (err: any) {
+      setError(err.message || 'Failed to create counter');
+    } finally {
+      setIsLoading(false);
+    }
+  };
+
+  return (
+    <div className="fixed inset-0 bg-gray-600 bg-opacity-50 overflow-y-auto h-full w-full z-50">
+      <div className="relative top-20 mx-auto p-5 border w-96 shadow-lg rounded-md bg-white">
+        <div className="flex justify-between items-center mb-4">
+          <h3 className="text-lg font-medium text-gray-900">Create New Counter</h3>
+          <button
+            onClick={onClose}
+            className="text-gray-400 hover:text-gray-600"
+          >
+            <X className="h-6 w-6" />
+          </button>
+        </div>
+
+        {error && (
+          <div className="bg-red-50 border border-red-200 text-red-700 px-4 py-3 rounded-md mb-4">
+            {error}
+          </div>
+        )}
+
+        <form onSubmit={handleSubmit(onSubmit)} className="space-y-4">
+          <div>
+            <label htmlFor="name" className="block text-sm font-medium text-gray-700">
+              Name *
+            </label>
+            <input
+              {...register('name', { 
+                required: 'Name is required',
+                maxLength: { value: 100, message: 'Name must be less than 100 characters' }
+              })}
+              type="text"
+              className="input mt-1"
+              placeholder="e.g., Cigarettes Smoked"
+            />
+            {errors.name && (
+              <p className="mt-1 text-sm text-red-600">{errors.name.message}</p>
+            )}
+          </div>
+
+          <div>
+            <label htmlFor="description" className="block text-sm font-medium text-gray-700">
+              Description
+            </label>
+            <textarea
+              {...register('description', {
+                maxLength: { value: 500, message: 'Description must be less than 500 characters' }
+              })}
+              rows={3}
+              className="input mt-1"
+              placeholder="Optional description..."
+            />
+            {errors.description && (
+              <p className="mt-1 text-sm text-red-600">{errors.description.message}</p>
+            )}
+          </div>
+
+          <div className="flex justify-end space-x-3 pt-4">
+            <button
+              type="button"
+              onClick={onClose}
+              className="btn btn-secondary"
+            >
+              Cancel
+            </button>
+            <button
+              type="submit"
+              disabled={isLoading}
+              className="btn btn-primary disabled:opacity-50 disabled:cursor-not-allowed"
+            >
+              {isLoading ? 'Creating...' : 'Create Counter'}
+            </button>
+          </div>
+        </form>
+      </div>
+    </div>
+  );
+};
--- a/frontend/src/components/Dashboard.tsx
+++ b/frontend/src/components/Dashboard.tsx
@@ -0,0 +1,145 @@
+import React, { useState } from 'react';
+import { Link } from 'react-router-dom';
+import { useCounters } from '../hooks/useCounters';
+import { useAuth } from '../hooks/useAuth';
+import { CreateCounterModal } from './CreateCounterModal';
+import { CounterCard } from './CounterCard';
+import { Plus, Search, TrendingUp, Calendar, Clock } from 'lucide-react';
+
+export const Dashboard: React.FC = () => {
+  const { counters, isLoading, error, searchCounters } = useCounters();
+  const { isAuthenticated } = useAuth();
+  const [showCreateModal, setShowCreateModal] = useState(false);
+  const [searchQuery, setSearchQuery] = useState('');
+
+  const handleSearch = (query: string) => {
+    setSearchQuery(query);
+    searchCounters(query);
+  };
+
+  const totalCounters = counters.length;
+  const totalValue = counters.reduce((sum, counter) => sum + counter.total_value, 0);
+  const todayValue = counters.reduce((sum, counter) => sum + counter.today_value, 0);
+
+  if (error) {
+    return (
+      <div className="bg-red-50 border border-red-200 text-red-700 px-4 py-3 rounded-md">
+        {error}
+      </div>
+    );
+  }
+
+  return (
+    <div className="space-y-6">
+      {/* Header */}
+      <div className="flex justify-between items-center">
+        <div>
+          <h1 className="text-3xl font-bold text-gray-900">Dashboard</h1>
+          <p className="text-gray-600 mt-1">
+            {isAuthenticated 
+              ? 'Manage your counters and track your progress'
+              : 'Track your habits and activities (data stored locally)'
+            }
+          </p>
+        </div>
+        <button
+          onClick={() => setShowCreateModal(true)}
+          className="btn btn-primary flex items-center space-x-2"
+        >
+          <Plus className="h-5 w-5" />
+          <span>New Counter</span>
+        </button>
+      </div>
+
+      {/* Stats Cards */}
+      <div className="grid grid-cols-1 md:grid-cols-3 gap-6">
+        <div className="card p-6">
+          <div className="flex items-center">
+            <div className="p-2 bg-primary-100 rounded-lg">
+              <TrendingUp className="h-6 w-6 text-primary-600" />
+            </div>
+            <div className="ml-4">
+              <p className="text-sm font-medium text-gray-600">Total Counters</p>
+              <p className="text-2xl font-bold text-gray-900">{totalCounters}</p>
+            </div>
+          </div>
+        </div>
+
+        <div className="card p-6">
+          <div className="flex items-center">
+            <div className="p-2 bg-green-100 rounded-lg">
+              <Calendar className="h-6 w-6 text-green-600" />
+            </div>
+            <div className="ml-4">
+              <p className="text-sm font-medium text-gray-600">Total Value</p>
+              <p className="text-2xl font-bold text-gray-900">{totalValue}</p>
+            </div>
+          </div>
+        </div>
+
+        <div className="card p-6">
+          <div className="flex items-center">
+            <div className="p-2 bg-blue-100 rounded-lg">
+              <Clock className="h-6 w-6 text-blue-600" />
+            </div>
+            <div className="ml-4">
+              <p className="text-sm font-medium text-gray-600">Today's Value</p>
+              <p className="text-2xl font-bold text-gray-900">{todayValue}</p>
+            </div>
+          </div>
+        </div>
+      </div>
+
+      {/* Search */}
+      <div className="relative">
+        <div className="absolute inset-y-0 left-0 pl-3 flex items-center pointer-events-none">
+          <Search className="h-5 w-5 text-gray-400" />
+        </div>
+        <input
+          type="text"
+          placeholder="Search counters..."
+          value={searchQuery}
+          onChange={(e) => handleSearch(e.target.value)}
+          className="input pl-10"
+        />
+      </div>
+
+      {/* Counters Grid */}
+      {isLoading ? (
+        <div className="flex justify-center items-center py-12">
+          <div className="animate-spin rounded-full h-12 w-12 border-b-2 border-primary-600"></div>
+        </div>
+      ) : counters.length === 0 ? (
+        <div className="text-center py-12">
+          <TrendingUp className="mx-auto h-12 w-12 text-gray-400" />
+          <h3 className="mt-2 text-sm font-medium text-gray-900">No counters</h3>
+          <p className="mt-1 text-sm text-gray-500">
+            Get started by creating your first counter.
+          </p>
+          <div className="mt-6">
+            <button
+              onClick={() => setShowCreateModal(true)}
+              className="btn btn-primary"
+            >
+              <Plus className="h-5 w-5 mr-2" />
+              New Counter
+            </button>
+          </div>
+        </div>
+      ) : (
+        <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 gap-6">
+          {counters.map((counter) => (
+            <CounterCard key={counter.id} counter={counter} />
+          ))}
+        </div>
+      )}
+
+      {/* Create Counter Modal */}
+      {showCreateModal && (
+        <CreateCounterModal
+          onClose={() => setShowCreateModal(false)}
+        />
+      )}
+    </div>
+  );
+};
--- a/frontend/src/components/Layout.tsx
+++ b/frontend/src/components/Layout.tsx
@@ -0,0 +1,97 @@
+import React, { useState } from 'react';
+import { Link, useNavigate } from 'react-router-dom';
+import { useAuth } from '../hooks/useAuth';
+import { LogOut, User, Plus, Search } from 'lucide-react';
+
+interface LayoutProps {
+  children: React.ReactNode;
+}
+
+export const Layout: React.FC<LayoutProps> = ({ children }) => {
+  const { user, isAuthenticated, logout } = useAuth();
+  const navigate = useNavigate();
+  const [showUserMenu, setShowUserMenu] = useState(false);
+
+  const handleLogout = () => {
+    logout();
+    navigate('/login');
+  };
+
+  return (
+    <div className="min-h-screen bg-gray-50">
+      {/* Header */}
+      <header className="bg-white shadow-sm border-b border-gray-200">
+        <div className="max-w-7xl mx-auto px-4 sm:px-6 lg:px-8">
+          <div className="flex justify-between items-center h-16">
+            {/* Logo */}
+            <Link to="/" className="flex items-center">
+              <div className="text-2xl font-bold text-primary-600">Counter</div>
+            </Link>
+
+            {/* Navigation */}
+            <nav className="flex items-center space-x-4">
+              <Link
+                to="/"
+                className="text-gray-700 hover:text-primary-600 px-3 py-2 rounded-md text-sm font-medium"
+              >
+                Dashboard
+              </Link>
+
+              {/* User Menu */}
+              <div className="relative">
+                <button
+                  onClick={() => setShowUserMenu(!showUserMenu)}
+                  className="flex items-center space-x-2 text-gray-700 hover:text-primary-600 px-3 py-2 rounded-md text-sm font-medium"
+                >
+                  <User className="h-5 w-5" />
+                  <span>{isAuthenticated ? user?.username : 'Anonymous'}</span>
+                </button>
+
+                {showUserMenu && (
+                  <div className="absolute right-0 mt-2 w-48 bg-white rounded-md shadow-lg py-1 z-50 border border-gray-200">
+                    {isAuthenticated ? (
+                      <>
+                        <div className="px-4 py-2 text-sm text-gray-700 border-b border-gray-200">
+                          {user?.email}
+                        </div>
+                        <button
+                          onClick={handleLogout}
+                          className="flex items-center w-full px-4 py-2 text-sm text-gray-700 hover:bg-gray-100"
+                        >
+                          <LogOut className="h-4 w-4 mr-2" />
+                          Logout
+                        </button>
+                      </>
+                    ) : (
+                      <>
+                        <Link
+                          to="/login"
+                          className="block px-4 py-2 text-sm text-gray-700 hover:bg-gray-100"
+                          onClick={() => setShowUserMenu(false)}
+                        >
+                          Login
+                        </Link>
+                        <Link
+                          to="/register"
+                          className="block px-4 py-2 text-sm text-gray-700 hover:bg-gray-100"
+                          onClick={() => setShowUserMenu(false)}
+                        >
+                          Register
+                        </Link>
+                      </>
+                    )}
+                  </div>
+                )}
+              </div>
+            </nav>
+          </div>
+        </div>
+      </header>
+
+      {/* Main Content */}
+      <main className="max-w-7xl mx-auto py-6 px-4 sm:px-6 lg:px-8">
+        {children}
+      </main>
+    </div>
+  );
+};
--- a/frontend/src/components/Login.tsx
+++ b/frontend/src/components/Login.tsx
@@ -0,0 +1,132 @@
+import React, { useState } from 'react';
+import { Link, useNavigate } from 'react-router-dom';
+import { useForm } from 'react-hook-form';
+import { useAuth } from '../hooks/useAuth';
+import { LoginRequest } from '../types';
+import { Eye, EyeOff } from 'lucide-react';
+
+export const Login: React.FC = () => {
+  const { login, isAuthenticated } = useAuth();
+  const navigate = useNavigate();
+  const [showPassword, setShowPassword] = useState(false);
+  const [isLoading, setIsLoading] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+
+  const {
+    register,
+    handleSubmit,
+    formState: { errors },
+  } = useForm<LoginRequest>();
+
+  // Redirect if already authenticated
+  React.useEffect(() => {
+    if (isAuthenticated) {
+      navigate('/');
+    }
+  }, [isAuthenticated, navigate]);
+
+  const onSubmit = async (data: LoginRequest) => {
+    setIsLoading(true);
+    setError(null);
+    try {
+      await login(data);
+      navigate('/');
+    } catch (err: any) {
+      setError(err.response?.data?.error || 'Login failed');
+    } finally {
+      setIsLoading(false);
+    }
+  };
+
+  return (
+    <div className="min-h-screen flex items-center justify-center bg-gray-50 py-12 px-4 sm:px-6 lg:px-8">
+      <div className="max-w-md w-full space-y-8">
+        <div>
+          <h2 className="mt-6 text-center text-3xl font-extrabold text-gray-900">
+            Sign in to your account
+          </h2>
+          <p className="mt-2 text-center text-sm text-gray-600">
+            Or{' '}
+            <Link
+              to="/register"
+              className="font-medium text-primary-600 hover:text-primary-500"
+            >
+              create a new account
+            </Link>
+          </p>
+        </div>
+        <form className="mt-8 space-y-6" onSubmit={handleSubmit(onSubmit)}>
+          {error && (
+            <div className="bg-red-50 border border-red-200 text-red-700 px-4 py-3 rounded-md">
+              {error}
+            </div>
+          )}
+          
+          <div className="space-y-4">
+            <div>
+              <label htmlFor="username" className="block text-sm font-medium text-gray-700">
+                Username
+              </label>
+              <input
+                {...register('username', { required: 'Username is required' })}
+                type="text"
+                className="input mt-1"
+                placeholder="Enter your username"
+              />
+              {errors.username && (
+                <p className="mt-1 text-sm text-red-600">{errors.username.message}</p>
+              )}
+            </div>
+
+            <div>
+              <label htmlFor="password" className="block text-sm font-medium text-gray-700">
+                Password
+              </label>
+              <div className="mt-1 relative">
+                <input
+                  {...register('password', { required: 'Password is required' })}
+                  type={showPassword ? 'text' : 'password'}
+                  className="input pr-10"
+                  placeholder="Enter your password"
+                />
+                <button
+                  type="button"
+                  className="absolute inset-y-0 right-0 pr-3 flex items-center"
+                  onClick={() => setShowPassword(!showPassword)}
+                >
+                  {showPassword ? (
+                    <EyeOff className="h-5 w-5 text-gray-400" />
+                  ) : (
+                    <Eye className="h-5 w-5 text-gray-400" />
+                  )}
+                </button>
+              </div>
+              {errors.password && (
+                <p className="mt-1 text-sm text-red-600">{errors.password.message}</p>
+              )}
+            </div>
+          </div>
+
+          <div>
+            <button
+              type="submit"
+              disabled={isLoading}
+              className="btn btn-primary w-full flex justify-center py-2 px-4 disabled:opacity-50 disabled:cursor-not-allowed"
+            >
+              {isLoading ? 'Signing in...' : 'Sign in'}
+            </button>
+          </div>
+
+          <div className="text-center">
+            <Link
+              to="/"
+              className="text-sm text-primary-600 hover:text-primary-500"
+            >
+              Continue as anonymous user
+            </Link>
+          </div>
+        </form>
+      </div>
+    </div>
+  );
+};
--- a/frontend/src/components/ProtectedRoute.tsx
+++ b/frontend/src/components/ProtectedRoute.tsx
@@ -0,0 +1,24 @@
+import React from 'react';
+import { Navigate, useLocation } from 'react-router-dom';
+import { useAuth } from '../hooks/useAuth';
+
+interface ProtectedRouteProps {
+  children: React.ReactNode;
+}
+
+export const ProtectedRoute: React.FC<ProtectedRouteProps> = ({ children }) => {
+  const { isAuthenticated, isLoading } = useAuth();
+  const location = useLocation();
+
+  if (isLoading) {
+    return (
+      <div className="min-h-screen flex items-center justify-center">
+        <div className="animate-spin rounded-full h-32 w-32 border-b-2 border-primary-600"></div>
+      </div>
+    );
+  }
+
+  // Allow access to authenticated users or anonymous users
+  // The app works for both authenticated and anonymous users
+  return <>{children}</>;
+};
--- a/frontend/src/components/Register.tsx
+++ b/frontend/src/components/Register.tsx
@@ -0,0 +1,185 @@
+import React, { useState } from 'react';
+import { Link, useNavigate } from 'react-router-dom';
+import { useForm } from 'react-hook-form';
+import { useAuth } from '../hooks/useAuth';
+import { RegisterRequest } from '../types';
+import { Eye, EyeOff } from 'lucide-react';
+
+export const Register: React.FC = () => {
+  const { register: registerUser, isAuthenticated } = useAuth();
+  const navigate = useNavigate();
+  const [showPassword, setShowPassword] = useState(false);
+  const [isLoading, setIsLoading] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+
+  const {
+    register,
+    handleSubmit,
+    watch,
+    formState: { errors },
+  } = useForm<RegisterRequest & { confirmPassword: string }>();
+
+  const password = watch('password');
+
+  // Redirect if already authenticated
+  React.useEffect(() => {
+    if (isAuthenticated) {
+      navigate('/');
+    }
+  }, [isAuthenticated, navigate]);
+
+  const onSubmit = async (data: RegisterRequest & { confirmPassword: string }) => {
+    setIsLoading(true);
+    setError(null);
+    try {
+      await registerUser({
+        username: data.username,
+        email: data.email,
+        password: data.password,
+      });
+      navigate('/');
+    } catch (err: any) {
+      setError(err.response?.data?.error || 'Registration failed');
+    } finally {
+      setIsLoading(false);
+    }
+  };
+
+  return (
+    <div className="min-h-screen flex items-center justify-center bg-gray-50 py-12 px-4 sm:px-6 lg:px-8">
+      <div className="max-w-md w-full space-y-8">
+        <div>
+          <h2 className="mt-6 text-center text-3xl font-extrabold text-gray-900">
+            Create your account
+          </h2>
+          <p className="mt-2 text-center text-sm text-gray-600">
+            Or{' '}
+            <Link
+              to="/login"
+              className="font-medium text-primary-600 hover:text-primary-500"
+            >
+              sign in to your existing account
+            </Link>
+          </p>
+        </div>
+        <form className="mt-8 space-y-6" onSubmit={handleSubmit(onSubmit)}>
+          {error && (
+            <div className="bg-red-50 border border-red-200 text-red-700 px-4 py-3 rounded-md">
+              {error}
+            </div>
+          )}
+          
+          <div className="space-y-4">
+            <div>
+              <label htmlFor="username" className="block text-sm font-medium text-gray-700">
+                Username
+              </label>
+              <input
+                {...register('username', { 
+                  required: 'Username is required',
+                  minLength: { value: 3, message: 'Username must be at least 3 characters' },
+                  maxLength: { value: 50, message: 'Username must be less than 50 characters' }
+                })}
+                type="text"
+                className="input mt-1"
+                placeholder="Choose a username"
+              />
+              {errors.username && (
+                <p className="mt-1 text-sm text-red-600">{errors.username.message}</p>
+              )}
+            </div>
+
+            <div>
+              <label htmlFor="email" className="block text-sm font-medium text-gray-700">
+                Email
+              </label>
+              <input
+                {...register('email', { 
+                  required: 'Email is required',
+                  pattern: {
+                    value: /^[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,}$/i,
+                    message: 'Invalid email address'
+                  }
+                })}
+                type="email"
+                className="input mt-1"
+                placeholder="Enter your email"
+              />
+              {errors.email && (
+                <p className="mt-1 text-sm text-red-600">{errors.email.message}</p>
+              )}
+            </div>
+
+            <div>
+              <label htmlFor="password" className="block text-sm font-medium text-gray-700">
+                Password
+              </label>
+              <div className="mt-1 relative">
+                <input
+                  {...register('password', { 
+                    required: 'Password is required',
+                    minLength: { value: 6, message: 'Password must be at least 6 characters' }
+                  })}
+                  type={showPassword ? 'text' : 'password'}
+                  className="input pr-10"
+                  placeholder="Create a password"
+                />
+                <button
+                  type="button"
+                  className="absolute inset-y-0 right-0 pr-3 flex items-center"
+                  onClick={() => setShowPassword(!showPassword)}
+                >
+                  {showPassword ? (
+                    <EyeOff className="h-5 w-5 text-gray-400" />
+                  ) : (
+                    <Eye className="h-5 w-5 text-gray-400" />
+                  )}
+                </button>
+              </div>
+              {errors.password && (
+                <p className="mt-1 text-sm text-red-600">{errors.password.message}</p>
+              )}
+            </div>
+
+            <div>
+              <label htmlFor="confirmPassword" className="block text-sm font-medium text-gray-700">
+                Confirm Password
+              </label>
+              <input
+                {...register('confirmPassword', { 
+                  required: 'Please confirm your password',
+                  validate: value => value === password || 'Passwords do not match'
+                })}
+                type="password"
+                className="input mt-1"
+                placeholder="Confirm your password"
+              />
+              {errors.confirmPassword && (
+                <p className="mt-1 text-sm text-red-600">{errors.confirmPassword.message}</p>
+              )}
+            </div>
+          </div>
+
+          <div>
+            <button
+              type="submit"
+              disabled={isLoading}
+              className="btn btn-primary w-full flex justify-center py-2 px-4 disabled:opacity-50 disabled:cursor-not-allowed"
+            >
+              {isLoading ? 'Creating account...' : 'Create account'}
+            </button>
+          </div>
+
+          <div className="text-center">
+            <Link
+              to="/"
+              className="text-sm text-primary-600 hover:text-primary-500"
+            >
+              Continue as anonymous user
+            </Link>
+          </div>
+        </form>
+      </div>
+    </div>
+  );
+};
--- a/frontend/src/hooks/useAuth.tsx
+++ b/frontend/src/hooks/useAuth.tsx
@@ -0,0 +1,111 @@
+import { useState, useEffect, createContext, useContext, ReactNode } from 'react';
+import { User, AuthResponse, RegisterRequest, LoginRequest } from '../types';
+import { authAPI } from '../services/api';
+import { localStorageService } from '../services/localStorage';
+
+interface AuthContextType {
+  user: User | null;
+  isAuthenticated: boolean;
+  isLoading: boolean;
+  login: (data: LoginRequest) => Promise<void>;
+  register: (data: RegisterRequest) => Promise<void>;
+  logout: () => void;
+  refreshUser: () => Promise<void>;
+}
+
+const AuthContext = createContext<AuthContextType | undefined>(undefined);
+
+export const useAuth = () => {
+  const context = useContext(AuthContext);
+  if (context === undefined) {
+    throw new Error('useAuth must be used within an AuthProvider');
+  }
+  return context;
+};
+
+interface AuthProviderProps {
+  children: ReactNode;
+}
+
+export const AuthProvider = ({ children }: AuthProviderProps) => {
+  const [user, setUser] = useState<User | null>(null);
+  const [isLoading, setIsLoading] = useState(true);
+
+  const isAuthenticated = !!user;
+
+  useEffect(() => {
+    const initAuth = async () => {
+      const token = localStorageService.getAuthToken();
+      if (token) {
+        try {
+          const response = await authAPI.getCurrentUser();
+          setUser(response.data);
+        } catch (error) {
+          console.error('Failed to get current user:', error);
+          localStorageService.clearAuth();
+        }
+      }
+      setIsLoading(false);
+    };
+
+    initAuth();
+  }, []);
+
+  const login = async (data: LoginRequest) => {
+    try {
+      const response = await authAPI.login(data);
+      const { token, user: userData } = response.data;
+      
+      localStorageService.setAuthToken(token);
+      localStorageService.setUser(userData);
+      setUser(userData);
+    } catch (error) {
+      throw error;
+    }
+  };
+
+  const register = async (data: RegisterRequest) => {
+    try {
+      const response = await authAPI.register(data);
+      const { token, user: userData } = response.data;
+      
+      localStorageService.setAuthToken(token);
+      localStorageService.setUser(userData);
+      setUser(userData);
+    } catch (error) {
+      throw error;
+    }
+  };
+
+  const logout = () => {
+    localStorageService.clearAuth();
+    setUser(null);
+  };
+
+  const refreshUser = async () => {
+    try {
+      const response = await authAPI.getCurrentUser();
+      setUser(response.data);
+      localStorageService.setUser(response.data);
+    } catch (error) {
+      console.error('Failed to refresh user:', error);
+      logout();
+    }
+  };
+
+  const value: AuthContextType = {
+    user,
+    isAuthenticated,
+    isLoading,
+    login,
+    register,
+    logout,
+    refreshUser,
+  };
+
+  return (
+    <AuthContext.Provider value={value}>
+      {children}
+    </AuthContext.Provider>
+  );
+};
--- a/frontend/src/hooks/useCounters.tsx
+++ b/frontend/src/hooks/useCounters.tsx
@@ -0,0 +1,191 @@
+import { useState, useEffect } from 'react';
+import { CounterWithStats, AnonymousCounter, CreateCounterRequest, UpdateCounterRequest, IncrementRequest } from '../types';
+import { countersAPI } from '../services/api';
+import { localStorageService } from '../services/localStorage';
+import { useAuth } from './useAuth';
+
+export const useCounters = () => {
+  const { isAuthenticated } = useAuth();
+  const [counters, setCounters] = useState<CounterWithStats[]>([]);
+  const [anonymousCounters, setAnonymousCounters] = useState<AnonymousCounter[]>([]);
+  const [isLoading, setIsLoading] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+
+  // Load counters based on authentication status
+  useEffect(() => {
+    if (isAuthenticated) {
+      loadCounters();
+    } else {
+      loadAnonymousCounters();
+    }
+  }, [isAuthenticated]);
+
+  const loadCounters = async (search?: string) => {
+    setIsLoading(true);
+    setError(null);
+    try {
+      const response = await countersAPI.getCounters(search);
+      setCounters(response.data);
+    } catch (err: any) {
+      setError(err.response?.data?.error || 'Failed to load counters');
+    } finally {
+      setIsLoading(false);
+    }
+  };
+
+  const loadAnonymousCounters = () => {
+    const stored = localStorageService.getAnonymousCounters();
+    setAnonymousCounters(stored);
+  };
+
+  const createCounter = async (data: CreateCounterRequest) => {
+    if (isAuthenticated) {
+      try {
+        const response = await countersAPI.createCounter(data);
+        await loadCounters(); // Refresh the list
+        return response.data;
+      } catch (err: any) {
+        throw new Error(err.response?.data?.error || 'Failed to create counter');
+      }
+    } else {
+      // Create anonymous counter
+      const newCounter: AnonymousCounter = {
+        id: localStorageService.generateId(),
+        name: data.name,
+        description: data.description,
+        total_value: 0,
+        entries: {},
+        created_at: new Date().toISOString(),
+        updated_at: new Date().toISOString(),
+      };
+      
+      localStorageService.addAnonymousCounter(newCounter);
+      loadAnonymousCounters();
+      return newCounter;
+    }
+  };
+
+  const updateCounter = async (id: number | string, data: UpdateCounterRequest) => {
+    if (isAuthenticated) {
+      try {
+        const response = await countersAPI.updateCounter(id as number, data);
+        await loadCounters(); // Refresh the list
+        return response.data;
+      } catch (err: any) {
+        throw new Error(err.response?.data?.error || 'Failed to update counter');
+      }
+    } else {
+      // Update anonymous counter
+      const updated = { ...data, updated_at: new Date().toISOString() };
+      localStorageService.updateAnonymousCounter(id as string, updated);
+      loadAnonymousCounters();
+      return { id, ...updated };
+    }
+  };
+
+  const deleteCounter = async (id: number | string) => {
+    if (isAuthenticated) {
+      try {
+        await countersAPI.deleteCounter(id as number);
+        await loadCounters(); // Refresh the list
+      } catch (err: any) {
+        throw new Error(err.response?.data?.error || 'Failed to delete counter');
+      }
+    } else {
+      // Delete anonymous counter
+      localStorageService.deleteAnonymousCounter(id as string);
+      loadAnonymousCounters();
+    }
+  };
+
+  const incrementCounter = async (id: number | string, value: number) => {
+    if (isAuthenticated) {
+      try {
+        const response = await countersAPI.incrementCounter(id as number, { value });
+        await loadCounters(); // Refresh the list
+        return response.data;
+      } catch (err: any) {
+        throw new Error(err.response?.data?.error || 'Failed to increment counter');
+      }
+    } else {
+      // Increment anonymous counter
+      const today = localStorageService.getTodayString();
+      const counter = anonymousCounters.find(c => c.id === id);
+      if (counter) {
+        const newTotal = counter.total_value + value;
+        const newEntries = { ...counter.entries };
+        newEntries[today] = (newEntries[today] || 0) + value;
+        
+        const updated = {
+          total_value: newTotal,
+          entries: newEntries,
+          updated_at: new Date().toISOString(),
+        };
+        
+        localStorageService.updateAnonymousCounter(id as string, updated);
+        loadAnonymousCounters();
+        return { id, ...updated };
+      }
+      throw new Error('Counter not found');
+    }
+  };
+
+  const searchCounters = (search: string) => {
+    if (isAuthenticated) {
+      loadCounters(search);
+    } else {
+      // Filter anonymous counters locally
+      const filtered = localStorageService.getAnonymousCounters().filter(counter =>
+        counter.name.toLowerCase().includes(search.toLowerCase()) ||
+        counter.description.toLowerCase().includes(search.toLowerCase())
+      );
+      setAnonymousCounters(filtered);
+    }
+  };
+
+  // Convert anonymous counters to CounterWithStats format for consistent UI
+  const getDisplayCounters = (): CounterWithStats[] => {
+    if (isAuthenticated) {
+      return counters;
+    } else {
+      return anonymousCounters.map(counter => ({
+        id: parseInt(counter.id), // Convert string ID to number for display
+        name: counter.name,
+        description: counter.description,
+        created_at: counter.created_at,
+        updated_at: counter.updated_at,
+        total_value: counter.total_value,
+        today_value: counter.entries[localStorageService.getTodayString()] || 0,
+        week_value: Object.entries(counter.entries)
+          .filter(([date]) => {
+            const entryDate = new Date(date);
+            const weekAgo = new Date();
+            weekAgo.setDate(weekAgo.getDate() - 7);
+            return entryDate >= weekAgo;
+          })
+          .reduce((sum, [, value]) => sum + (value as number), 0),
+        month_value: Object.entries(counter.entries)
+          .filter(([date]) => {
+            const entryDate = new Date(date);
+            const monthAgo = new Date();
+            monthAgo.setMonth(monthAgo.getMonth() - 1);
+            return entryDate >= monthAgo;
+          })
+          .reduce((sum, [, value]) => sum + (value as number), 0),
+        entry_count: Object.values(counter.entries).reduce((sum: number, value: unknown) => sum + Math.abs(value as number), 0),
+      }));
+    }
+  };
+
+  return {
+    counters: getDisplayCounters(),
+    isLoading,
+    error,
+    createCounter,
+    updateCounter,
+    deleteCounter,
+    incrementCounter,
+    searchCounters,
+    refreshCounters: isAuthenticated ? loadCounters : loadAnonymousCounters,
+  };
+};
--- a/frontend/src/index.css
+++ b/frontend/src/index.css
@@ -0,0 +1,20 @@
+@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&display=swap');
+
+body {
+  margin: 0;
+  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen',
+    'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue',
+    sans-serif;
+  -webkit-font-smoothing: antialiased;
+  -moz-osx-font-smoothing: grayscale;
+  background-color: #f8fafc;
+}
+
+code {
+  font-family: source-code-pro, Menlo, Monaco, Consolas, 'Courier New',
+    monospace;
+}
+
+* {
+  box-sizing: border-box;
+}
--- a/frontend/src/index.tsx
+++ b/frontend/src/index.tsx
@@ -0,0 +1,13 @@
+import React from 'react';
+import ReactDOM from 'react-dom/client';
+import './index.css';
+import App from './App';
+
+const root = ReactDOM.createRoot(
+  document.getElementById('root') as HTMLElement
+);
+root.render(
+  <React.StrictMode>
+    <App />
+  </React.StrictMode>
+);
--- a/frontend/src/services/api.ts
+++ b/frontend/src/services/api.ts
@@ -0,0 +1,93 @@
+import axios, { AxiosResponse } from 'axios';
+import {
+  AuthResponse,
+  RegisterRequest,
+  LoginRequest,
+  Counter,
+  CounterWithStats,
+  CounterEntry,
+  CreateCounterRequest,
+  UpdateCounterRequest,
+  IncrementRequest,
+  CounterStats,
+  User,
+} from '../types';
+
+const API_BASE_URL = process.env.REACT_APP_API_URL || '/api/v1';
+
+// Create axios instance
+const api = axios.create({
+  baseURL: API_BASE_URL,
+  headers: {
+    'Content-Type': 'application/json',
+  },
+});
+
+// Add auth token to requests
+api.interceptors.request.use((config) => {
+  const token = localStorage.getItem('token');
+  if (token) {
+    config.headers.Authorization = `Bearer ${token}`;
+  }
+  return config;
+});
+
+// Handle auth errors
+api.interceptors.response.use(
+  (response) => response,
+  (error) => {
+    if (error.response?.status === 401) {
+      localStorage.removeItem('token');
+      localStorage.removeItem('user');
+      window.location.href = '/login';
+    }
+    return Promise.reject(error);
+  }
+);
+
+// Auth API
+export const authAPI = {
+  register: (data: RegisterRequest): Promise<AxiosResponse<AuthResponse>> =>
+    api.post('/auth/register', data),
+  
+  login: (data: LoginRequest): Promise<AxiosResponse<AuthResponse>> =>
+    api.post('/auth/login', data),
+  
+  getCurrentUser: (): Promise<AxiosResponse<User>> =>
+    api.get('/auth/me'),
+};
+
+// Counters API
+export const countersAPI = {
+  getCounters: (search?: string): Promise<AxiosResponse<CounterWithStats[]>> => {
+    const params = search ? { search } : {};
+    return api.get('/counters', { params });
+  },
+  
+  getCounter: (id: number): Promise<AxiosResponse<CounterWithStats>> =>
+    api.get(`/counters/${id}`),
+  
+  createCounter: (data: CreateCounterRequest): Promise<AxiosResponse<Counter>> =>
+    api.post('/counters', data),
+  
+  updateCounter: (id: number, data: UpdateCounterRequest): Promise<AxiosResponse<Counter>> =>
+    api.put(`/counters/${id}`, data),
+  
+  deleteCounter: (id: number): Promise<AxiosResponse<{ message: string }>> =>
+    api.delete(`/counters/${id}`),
+  
+  incrementCounter: (id: number, data: IncrementRequest): Promise<AxiosResponse<CounterEntry>> =>
+    api.post(`/counters/${id}/increment`, data),
+  
+  getCounterEntries: (id: number, startDate?: string, endDate?: string): Promise<AxiosResponse<CounterEntry[]>> => {
+    const params: any = {};
+    if (startDate) params.start_date = startDate;
+    if (endDate) params.end_date = endDate;
+    return api.get(`/counters/${id}/entries`, { params });
+  },
+  
+  getCounterStats: (id: number): Promise<AxiosResponse<CounterStats>> =>
+    api.get(`/counters/${id}/stats`),
+};
+
+export default api;
--- a/frontend/src/services/localStorage.ts
+++ b/frontend/src/services/localStorage.ts
@@ -0,0 +1,90 @@
+import { AnonymousCounter } from '../types';
+
+const ANONYMOUS_COUNTERS_KEY = 'anonymous_counters';
+
+export const localStorageService = {
+  // Anonymous counters
+  getAnonymousCounters: (): AnonymousCounter[] => {
+    try {
+      const data = localStorage.getItem(ANONYMOUS_COUNTERS_KEY);
+      return data ? JSON.parse(data) : [];
+    } catch (error) {
+      console.error('Error loading anonymous counters:', error);
+      return [];
+    }
+  },
+
+  saveAnonymousCounters: (counters: AnonymousCounter[]): void => {
+    try {
+      localStorage.setItem(ANONYMOUS_COUNTERS_KEY, JSON.stringify(counters));
+    } catch (error) {
+      console.error('Error saving anonymous counters:', error);
+    }
+  },
+
+  addAnonymousCounter: (counter: AnonymousCounter): void => {
+    const counters = localStorageService.getAnonymousCounters();
+    counters.push(counter);
+    localStorageService.saveAnonymousCounters(counters);
+  },
+
+  updateAnonymousCounter: (id: string, updates: Partial<AnonymousCounter>): void => {
+    const counters = localStorageService.getAnonymousCounters();
+    const index = counters.findIndex(c => c.id === id);
+    if (index !== -1) {
+      counters[index] = { ...counters[index], ...updates };
+      localStorageService.saveAnonymousCounters(counters);
+    }
+  },
+
+  deleteAnonymousCounter: (id: string): void => {
+    const counters = localStorageService.getAnonymousCounters();
+    const filtered = counters.filter(c => c.id !== id);
+    localStorageService.saveAnonymousCounters(filtered);
+  },
+
+  // Auth
+  setAuthToken: (token: string): void => {
+    localStorage.setItem('token', token);
+  },
+
+  getAuthToken: (): string | null => {
+    return localStorage.getItem('token');
+  },
+
+  removeAuthToken: (): void => {
+    localStorage.removeItem('token');
+  },
+
+  setUser: (user: any): void => {
+    localStorage.setItem('user', JSON.stringify(user));
+  },
+
+  getUser: (): any => {
+    try {
+      const data = localStorage.getItem('user');
+      return data ? JSON.parse(data) : null;
+    } catch (error) {
+      console.error('Error loading user:', error);
+      return null;
+    }
+  },
+
+  removeUser: (): void => {
+    localStorage.removeItem('user');
+  },
+
+  clearAuth: (): void => {
+    localStorageService.removeAuthToken();
+    localStorageService.removeUser();
+  },
+
+  // Utility
+  generateId: (): string => {
+    return Date.now().toString(36) + Math.random().toString(36).substr(2);
+  },
+
+  getTodayString: (): string => {
+    return new Date().toISOString().split('T')[0];
+  },
+};
--- a/frontend/src/types/index.ts
+++ b/frontend/src/types/index.ts
@@ -0,0 +1,81 @@
+export interface User {
+  id: number;
+  username: string;
+  email: string;
+  created_at: string;
+  updated_at: string;
+}
+
+export interface Counter {
+  id: number;
+  user_id?: number;
+  name: string;
+  description: string;
+  created_at: string;
+  updated_at: string;
+}
+
+export interface CounterEntry {
+  id: number;
+  counter_id: number;
+  value: number;
+  date: string;
+  created_at: string;
+}
+
+export interface CounterWithStats extends Counter {
+  total_value: number;
+  today_value: number;
+  week_value: number;
+  month_value: number;
+  entry_count: number;
+}
+
+export interface AnonymousCounter {
+  id: string;
+  name: string;
+  description: string;
+  total_value: number;
+  entries: Record<string, number>; // date -> count
+  created_at: string;
+  updated_at: string;
+}
+
+export interface AuthResponse {
+  token: string;
+  user: User;
+}
+
+export interface RegisterRequest {
+  username: string;
+  email: string;
+  password: string;
+}
+
+export interface LoginRequest {
+  username: string;
+  password: string;
+}
+
+export interface CreateCounterRequest {
+  name: string;
+  description: string;
+}
+
+export interface UpdateCounterRequest {
+  name: string;
+  description: string;
+}
+
+export interface IncrementRequest {
+  value: number;
+}
+
+export interface DailyStat {
+  date: string;
+  total: number;
+}
+
+export interface CounterStats {
+  daily_stats: DailyStat[];
+}
--- a/frontend/tailwind.config.js
+++ b/frontend/tailwind.config.js
@@ -0,0 +1,25 @@
+/** @type {import('tailwindcss').Config} */
+module.exports = {
+  content: [
+    "./src/**/*.{js,jsx,ts,tsx}",
+  ],
+  theme: {
+    extend: {
+      colors: {
+        primary: {
+          50: '#eff6ff',
+          100: '#dbeafe',
+          200: '#bfdbfe',
+          300: '#93c5fd',
+          400: '#60a5fa',
+          500: '#3b82f6',
+          600: '#2563eb',
+          700: '#1d4ed8',
+          800: '#1e40af',
+          900: '#1e3a8a',
+        },
+      },
+    },
+  },
+  plugins: [],
+}
--- a/frontend/tsconfig.json
+++ b/frontend/tsconfig.json
@@ -0,0 +1,26 @@
+{
+  "compilerOptions": {
+    "target": "es5",
+    "lib": [
+      "dom",
+      "dom.iterable",
+      "es6"
+    ],
+    "allowJs": true,
+    "skipLibCheck": true,
+    "esModuleInterop": true,
+    "allowSyntheticDefaultImports": true,
+    "strict": true,
+    "forceConsistentCasingInFileNames": true,
+    "noFallthroughCasesInSwitch": true,
+    "module": "esnext",
+    "moduleResolution": "node",
+    "resolveJsonModule": true,
+    "isolatedModules": true,
+    "noEmit": true,
+    "jsx": "react-jsx"
+  },
+  "include": [
+    "src"
+  ]
+}
--- a/go.mod
+++ b/go.mod
@@ -2,6 +2,15 @@ module counter

 go 1.21

+require (
+	github.com/gin-contrib/cors v1.7.0
+	github.com/gin-gonic/gin v1.10.1
+	github.com/golang-jwt/jwt/v5 v5.2.1
+	github.com/joho/godotenv v1.5.1
+	github.com/lib/pq v1.10.9
+	golang.org/x/crypto v0.23.0
+)
+
 require (
 	github.com/bytedance/sonic v1.11.6 // indirect
 	github.com/bytedance/sonic/loader v0.1.1 // indirect
@@ -9,13 +18,13 @@ require (
 	github.com/cloudwego/iasm v0.2.0 // indirect
 	github.com/gabriel-vasile/mimetype v1.4.3 // indirect
 	github.com/gin-contrib/sse v0.1.0 // indirect
-	github.com/gin-gonic/gin v1.10.1 // indirect
 	github.com/go-playground/locales v0.14.1 // indirect
 	github.com/go-playground/universal-translator v0.18.1 // indirect
 	github.com/go-playground/validator/v10 v10.20.0 // indirect
 	github.com/goccy/go-json v0.10.2 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
 	github.com/klauspost/cpuid/v2 v2.2.7 // indirect
+	github.com/kr/text v0.2.0 // indirect
 	github.com/leodido/go-urn v1.4.0 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
@@ -24,7 +33,6 @@ require (
 	github.com/twitchyliquid64/golang-asm v0.15.1 // indirect
 	github.com/ugorji/go/codec v1.2.12 // indirect
 	golang.org/x/arch v0.8.0 // indirect
-	golang.org/x/crypto v0.23.0 // indirect
 	golang.org/x/net v0.25.0 // indirect
 	golang.org/x/sys v0.20.0 // indirect
 	golang.org/x/text v0.15.0 // indirect
--- a/go.sum
+++ b/go.sum
@@ -6,14 +6,20 @@ github.com/cloudwego/base64x v0.1.4 h1:jwCgWpFanWmN8xoIUHa2rtzmkd5J2plF/dnLS6Xd/
 github.com/cloudwego/base64x v0.1.4/go.mod h1:0zlkT4Wn5C6NdauXdJRhSKRlJvmclQ1hhJgA0rcu/8w=
 github.com/cloudwego/iasm v0.2.0 h1:1KNIy1I1H9hNNFEEH3DVnI4UujN+1zjpuk6gwHLTssg=
 github.com/cloudwego/iasm v0.2.0/go.mod h1:8rXZaNYT2n95jn+zTI1sDr+IgcD2GVs0nlbbQPiEFhY=
+github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/gabriel-vasile/mimetype v1.4.3 h1:in2uUcidCuFcDKtdcBxlR0rJ1+fsokWf+uqxgUFjbI0=
 github.com/gabriel-vasile/mimetype v1.4.3/go.mod h1:d8uq/6HKRL6CGdk+aubisF/M5GcPfT7nKyLpA0lbSSk=
+github.com/gin-contrib/cors v1.7.0 h1:wZX2wuZ0o7rV2/1i7gb4Jn+gW7HBqaP91fizJkBUJOA=
+github.com/gin-contrib/cors v1.7.0/go.mod h1:cI+h6iOAyxKRtUtC6iF/Si1KSFvGm/gK+kshxlCi8ro=
 github.com/gin-contrib/sse v0.1.0 h1:Y/yl/+YNO8GZSjAhjMsSuLt29uWRFHdHYUb5lYOV9qE=
 github.com/gin-contrib/sse v0.1.0/go.mod h1:RHrZQHXnP2xjPF+u1gW/2HnVO7nvIa9PG3Gm+fLHvGI=
 github.com/gin-gonic/gin v1.10.1 h1:T0ujvqyCSqRopADpgPgiTT63DUQVSfojyME59Ei63pQ=
 github.com/gin-gonic/gin v1.10.1/go.mod h1:4PMNQiOhvDRa013RKVbsiNwoyezlm2rm0uX/T7kzp5Y=
+github.com/go-playground/assert/v2 v2.2.0 h1:JvknZsQTYeFEAhQwI4qEt9cyV5ONwRHC+lYKSsYSR8s=
+github.com/go-playground/assert/v2 v2.2.0/go.mod h1:VDjEfimB/XKnb+ZQfWdccd7VUvScMdVu0Titje2rxJ4=
 github.com/go-playground/locales v0.14.1 h1:EWaQ/wswjilfKLTECiXz7Rh+3BjFhfDFKv/oXslEjJA=
 github.com/go-playground/locales v0.14.1/go.mod h1:hxrqLVvrK65+Rwrd5Fc6F2O76J/NuW9t0sjnWqG1slY=
 github.com/go-playground/universal-translator v0.18.1 h1:Bcnm0ZwsGyWbCzImXv+pAJnYK9S473LQFuzCbDbfSFY=
@@ -22,15 +28,27 @@ github.com/go-playground/validator/v10 v10.20.0 h1:K9ISHbSaI0lyB2eWMPJo+kOS/FBEx
 github.com/go-playground/validator/v10 v10.20.0/go.mod h1:dbuPbCMFw/DrkbEynArYaCwl3amGuJotoKCe95atGMM=
 github.com/goccy/go-json v0.10.2 h1:CrxCmQqYDkv1z7lO7Wbh2HN93uovUHgrECaO5ZrCXAU=
 github.com/goccy/go-json v0.10.2/go.mod h1:6MelG93GURQebXPDq3khkgXZkazVtN9CRI+MGFi0w8I=
+github.com/golang-jwt/jwt/v5 v5.2.1 h1:OuVbFODueb089Lh128TAcimifWaLhJwVflnrgM17wHk=
+github.com/golang-jwt/jwt/v5 v5.2.1/go.mod h1:pqrtFR0X4osieyHYxtmOUWsAWrfe1Q5UVIyoH402zdk=
+github.com/google/go-cmp v0.5.5 h1:Khx7svrCpmxxtHBq5j2mp/xVjsi8hQMfNLvJFAlrGgU=
+github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
+github.com/joho/godotenv v1.5.1 h1:7eLL/+HRGLY0ldzfGMeQkb7vMd0as4CfYvUVzLqw0N0=
+github.com/joho/godotenv v1.5.1/go.mod h1:f4LDr5Voq0i2e/R5DDNOoa2zzDfwtkZa6DnEwAbqwq4=
 github.com/json-iterator/go v1.1.12 h1:PV8peI4a0ysnczrg+LtxykD8LfKY9ML6u2jnxaEnrnM=
 github.com/json-iterator/go v1.1.12/go.mod h1:e30LSqwooZae/UwlEbR2852Gd8hjQvJoHmT4TnhNGBo=
 github.com/klauspost/cpuid/v2 v2.0.9/go.mod h1:FInQzS24/EEf25PyTYn52gqo7WaD8xa0213Md/qVLRg=
 github.com/klauspost/cpuid/v2 v2.2.7 h1:ZWSB3igEs+d0qvnxR/ZBzXVmxkgt8DdzP6m9pfuVLDM=
 github.com/klauspost/cpuid/v2 v2.2.7/go.mod h1:Lcz8mBdAVJIBVzewtcLocK12l3Y+JytZYpaMropDUws=
 github.com/knz/go-libedit v1.10.1/go.mod h1:MZTVkCWyz0oBc7JOWP3wNAzd002ZbM/5hgShxwh4x8M=
+github.com/kr/pretty v0.3.0 h1:WgNl7dwNpEZ6jJ9k1snq4pZsg7DOEN8hP9Xw0Tsjwk0=
+github.com/kr/pretty v0.3.0/go.mod h1:640gp4NfQd8pI5XOwp5fnNeVWj67G7CFk/SaSQn7NBk=
+github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
+github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
 github.com/leodido/go-urn v1.4.0 h1:WT9HwE9SGECu3lg4d/dIA+jxlljEa1/ffXKmRjqdmIQ=
 github.com/leodido/go-urn v1.4.0/go.mod h1:bvxc+MVxLKB4z00jd1z+Dvzr47oO32F/QSNjSBOlFxI=
+github.com/lib/pq v1.10.9 h1:YXG7RB+JIjhP29X+OtkiDnYaXQwpS4JEWq7dtCCRUEw=
+github.com/lib/pq v1.10.9/go.mod h1:AlVN5x4E4T544tWzH6hKfbfQvm3HdbOxrmggDNAPY9o=
 github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
 github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
 github.com/modern-go/concurrent v0.0.0-20180228061459-e0a39a4cb421/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=
@@ -40,7 +58,10 @@ github.com/modern-go/reflect2 v1.0.2 h1:xBagoLtFs94CBntxluKeaWgTMpvLxC4ur3nMaC9G
 github.com/modern-go/reflect2 v1.0.2/go.mod h1:yWuevngMOJpCy52FWWMvUC8ws7m/LJsjYzDa0/r8luk=
 github.com/pelletier/go-toml/v2 v2.2.2 h1:aYUidT7k73Pcl9nb2gScu7NSrKCSHIDE89b3+6Wq+LM=
 github.com/pelletier/go-toml/v2 v2.2.2/go.mod h1:1t835xjRzz80PqgE6HHgN2JOsmgYu/h4qDAS4n929Rs=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/rogpeppe/go-internal v1.8.0 h1:FCbCCtXNOY3UtUuHUYaghJg4y7Fd14rXifAYUAtL9R8=
+github.com/rogpeppe/go-internal v1.8.0/go.mod h1:WmiCO8CzOY8rg0OYDC4/i/2WRWAB6poM+XZ2dLUbcbE=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
 github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
@@ -51,6 +72,7 @@ github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/
 github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
 github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
 github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
+github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
 github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 github.com/twitchyliquid64/golang-asm v0.15.1 h1:SU5vSMR7hnwNxj24w34ZyCi/FmDZTkS4MhqMhdFk5YI=
 github.com/twitchyliquid64/golang-asm v0.15.1/go.mod h1:a1lVb/DtPvCB8fslRZhAngC2+aY1QWCk3Cedj/Gdt08=
@@ -69,9 +91,13 @@ golang.org/x/sys v0.20.0 h1:Od9JTbYCk261bKm4M/mw7AklTlFYIa0bIp9BgSm1S8Y=
 golang.org/x/sys v0.20.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/text v0.15.0 h1:h1V/4gjBv8v9cjcR6+AR5+/cIYK5N/WAgiv4xlsEtAk=
 golang.org/x/text v0.15.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 google.golang.org/protobuf v1.34.1 h1:9ddQBjfCyZPOHPUiPxpYESBLc+T8P3E+Vo4IbKZgFWg=
 google.golang.org/protobuf v1.34.1/go.mod h1:c6P6GXX6sHbq/GpV6MGZEdwhWPcYBgnhAHhKbcUYpos=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
+gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
--- a/main.go
+++ b/main.go
@@ -2,24 +2,92 @@ package main

 import (
 	"log"
-	"net/http"
+	"os"
+
+	"github.com/gin-contrib/cors"
+	"github.com/gin-gonic/gin"
+	"github.com/joho/godotenv"
 )

-func helloHandler(w http.ResponseWriter, r *http.Request) {
-	if r.Method != http.MethodGet {
-		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
-		return
+func main() {
+	// Load environment variables
+	if err := godotenv.Load(); err != nil {
+		log.Println("No .env file found, using system environment variables")
 	}

-	w.Header().Set("Content-Type", "text/plain")
-	w.WriteHeader(http.StatusOK)
-	w.Write([]byte("Hello world"))
-}
+	// Initialize JWT
+	InitJWT()

-func main() {
-	http.HandleFunc("/", helloHandler)
+	// Initialize database
+	if err := InitDB(); err != nil {
+		log.Fatal("Failed to initialize database:", err)
+	}
+
+	// Create tables
+	if err := CreateTables(); err != nil {
+		log.Fatal("Failed to create tables:", err)
+	}
+
+	// Set Gin mode
+	if os.Getenv("GIN_MODE") == "release" {
+		gin.SetMode(gin.ReleaseMode)
+	}
+
+	// Create Gin router
+	r := gin.Default()
+
+	// Configure CORS
+	config := cors.DefaultConfig()
+	config.AllowOrigins = []string{"http://localhost:3000", "http://localhost:5173"} // React dev servers
+	config.AllowMethods = []string{"GET", "POST", "PUT", "DELETE", "OPTIONS"}
+	config.AllowHeaders = []string{"Origin", "Content-Type", "Accept", "Authorization"}
+	config.AllowCredentials = true
+	r.Use(cors.New(config))
+
+	// Health check endpoint
+	r.GET("/health", func(c *gin.Context) {
+		c.JSON(200, gin.H{"status": "ok"})
+	})
+
+	// API routes
+	api := r.Group("/api/v1")
+	{
+		// Authentication routes
+		auth := api.Group("/auth")
+		{
+			auth.POST("/register", RegisterHandler)
+			auth.POST("/login", LoginHandler)
+			auth.GET("/me", AuthMiddleware(), GetCurrentUserHandler)
+		}
+
+		// Counter routes (protected)
+		counters := api.Group("/counters")
+		counters.Use(AuthMiddleware())
+		{
+			counters.POST("", CreateCounterHandler)
+			counters.GET("", GetCountersHandler)
+			counters.GET("/:id", GetCounterHandler)
+			counters.PUT("/:id", UpdateCounterHandler)
+			counters.DELETE("/:id", DeleteCounterHandler)
+			counters.POST("/:id/increment", IncrementCounterHandler)
+			counters.GET("/:id/entries", GetCounterEntriesHandler)
+			counters.GET("/:id/stats", GetCounterStatsHandler)
+		}
+	}
+
+	// Serve static files (React app)
+	r.Static("/static", "./frontend/build/static")
+	r.StaticFile("/", "./frontend/build/index.html")
+	r.NoRoute(func(c *gin.Context) {
+		c.File("./frontend/build/index.html")
+	})
+
+	// Start server
+	port := os.Getenv("PORT")
+	if port == "" {
+		port = "8080"
+	}

-	port := ":8080"
 	log.Printf("Server starting on port %s", port)
-	log.Fatal(http.ListenAndServe(port, nil))
+	log.Fatal(r.Run(":" + port))
 }
--- a/models.go
+++ b/models.go
@@ -0,0 +1,92 @@
+package main
+
+import (
+	"time"
+)
+
+// User represents a registered user
+type User struct {
+	ID        int       `json:"id" db:"id"`
+	Username  string    `json:"username" db:"username"`
+	Email     string    `json:"email" db:"email"`
+	Password  string    `json:"-" db:"password"` // Hidden from JSON
+	CreatedAt time.Time `json:"created_at" db:"created_at"`
+	UpdatedAt time.Time `json:"updated_at" db:"updated_at"`
+}
+
+// Counter represents a counter entity
+type Counter struct {
+	ID          int       `json:"id" db:"id"`
+	UserID      *int      `json:"user_id,omitempty" db:"user_id"` // nil for anonymous users
+	Name        string    `json:"name" db:"name"`
+	Description string    `json:"description" db:"description"`
+	CreatedAt   time.Time `json:"created_at" db:"created_at"`
+	UpdatedAt   time.Time `json:"updated_at" db:"updated_at"`
+}
+
+// CounterEntry represents a single increment/decrement entry
+type CounterEntry struct {
+	ID        int       `json:"id" db:"id"`
+	CounterID int       `json:"counter_id" db:"counter_id"`
+	Value     int       `json:"value" db:"value"` // +1 for increment, -1 for decrement
+	Date      time.Time `json:"date" db:"date"`
+	CreatedAt time.Time `json:"created_at" db:"created_at"`
+}
+
+// CounterWithStats represents a counter with aggregated statistics
+type CounterWithStats struct {
+	Counter
+	TotalValue int `json:"total_value"`
+	TodayValue int `json:"today_value"`
+	WeekValue  int `json:"week_value"`
+	MonthValue int `json:"month_value"`
+	EntryCount int `json:"entry_count"`
+}
+
+// AnonymousCounter represents a counter for anonymous users (stored in localStorage)
+type AnonymousCounter struct {
+	ID          string         `json:"id"`
+	Name        string         `json:"name"`
+	Description string         `json:"description"`
+	TotalValue  int            `json:"total_value"`
+	Entries     map[string]int `json:"entries"` // date -> count
+	CreatedAt   time.Time      `json:"created_at"`
+	UpdatedAt   time.Time      `json:"updated_at"`
+}
+
+// Request/Response DTOs
+
+type RegisterRequest struct {
+	Username string `json:"username" binding:"required,min=3,max=50"`
+	Email    string `json:"email" binding:"required,email"`
+	Password string `json:"password" binding:"required,min=6"`
+}
+
+type LoginRequest struct {
+	Username string `json:"username" binding:"required"`
+	Password string `json:"password" binding:"required"`
+}
+
+type AuthResponse struct {
+	Token string `json:"token"`
+	User  User   `json:"user"`
+}
+
+type CreateCounterRequest struct {
+	Name        string `json:"name" binding:"required,min=1,max=100"`
+	Description string `json:"description" max:"500"`
+}
+
+type UpdateCounterRequest struct {
+	Name        string `json:"name" binding:"required,min=1,max=100"`
+	Description string `json:"description" max:"500"`
+}
+
+type IncrementRequest struct {
+	Value int `json:"value" binding:"required"`
+}
+
+type CounterStatsRequest struct {
+	StartDate *time.Time `json:"start_date"`
+	EndDate   *time.Time `json:"end_date"`
+}