Habit Tracker API

A REST API for tracking personal habits and managing streaks, built with Node.js, TypeScript, Express, and PostgreSQL.

Features

• User authentication with JWT
• Create, read, update, and delete habits
• Daily habit tracking
• 7-day history view
• Automatic streak calculation
• Tag-based filtering
• Pagination support
• Rate limiting (100 requests/hour)

Tech Stack

• Runtime: Node.js with TypeScript
• Framework: Express
• Database: PostgreSQL
• ORM: Prisma
• Authentication: JWT + bcrypt
• Validation: express-validator
• Rate Limiting: express-rate-limit

Setup

Prerequisites

• Node.js (v18 or higher)
• PostgreSQL
• pnpm (or npm/yarn)

Installation

1. Clone the repository

git clone <repository-url>
cd habit-tracker-api

2. Install dependencies

pnpm install

3. Configure environment variables

Create a .env file in the root directory:

DATABASE_URL="postgresql://user:password@localhost:5432/habit_tracker?schema=public"
JWT_SECRET="your-secret-key-here"
PORT=3000

4. Run database migrations

pnpm prisma:migrate

5. Generate Prisma Client

pnpm prisma:generate

Running the Application

Development mode:

pnpm dev

Production build:

pnpm build
pnpm start

API Documentation

Authentication

All habit-related endpoints require JWT authentication. Include the token in the Authorization header:

Authorization: Bearer <your-jwt-token>

Endpoints

Auth

POST /register

Register a new user.

Request:

{
  "name": "John Doe",
  "email": "john@example.com",
  "password": "password123"
}

Response:

{
  "success": true,
  "message": "User registered successfully",
  "data": {
    "user": {
      "id": "uuid",
      "name": "John Doe",
      "email": "john@example.com"
    },
    "token": "jwt-token"
  }
}

POST /login

Authenticate user and get JWT.

Request:

{
  "email": "john@example.com",
  "password": "password123"
}

Response:

{
  "success": true,
  "message": "Login successful",
  "data": {
    "user": {
      "id": "uuid",
      "name": "John Doe",
      "email": "john@example.com"
    },
    "token": "jwt-token"
  }
}

Habits

POST /habits

Create a new habit.

Request:

{
  "title": "Morning Exercise",
  "description": "30 minutes of cardio",
  "frequency": "daily",
  "tags": ["health", "fitness"],
  "reminderTime": "07:00"
}

Response:

{
  "success": true,
  "message": "Habit created successfully",
  "data": {
    "id": "uuid",
    "title": "Morning Exercise",
    "description": "30 minutes of cardio",
    "frequency": "daily",
    "tags": ["health", "fitness"],
    "reminderTime": "07:00",
    "userId": "uuid",
    "createdAt": "2025-01-01T00:00:00.000Z",
    "updatedAt": "2025-01-01T00:00:00.000Z"
  }
}

GET /habits

Get all habits for the authenticated user.

Query Parameters:

• tag (optional): Filter by tag
• page (optional, default: 1): Page number
• limit (optional, default: 10): Items per page

Response:

{
  "success": true,
  "message": "Success",
  "data": {
    "habits": [...],
    "pagination": {
      "page": 1,
      "limit": 10,
      "total": 25,
      "totalPages": 3
    }
  }
}

GET /habits/:id

Get a specific habit.

Response:

{
  "success": true,
  "message": "Success",
  "data": {
    "id": "uuid",
    "title": "Morning Exercise",
    ...
  }
}

PUT /habits/:id

Update a habit.

Request (all fields optional):

{
  "title": "Updated Title",
  "description": "Updated description",
  "frequency": "weekly",
  "tags": ["new-tag"],
  "reminderTime": "08:00"
}

Response:

{
  "success": true,
  "message": "Habit updated successfully",
  "data": { ... }
}

DELETE /habits/:id

Delete a habit.

Response:

{
  "success": true,
  "message": "Habit deleted successfully",
  "data": null
}

Tracking

POST /habits/:id/track

Mark habit as completed for today.

Response:

{
  "success": true,
  "message": "Habit tracked successfully",
  "data": {
    "id": "uuid",
    "habitId": "uuid",
    "date": "2025-01-01",
    "completedAt": "2025-01-01T10:30:00.000Z"
  }
}

GET /habits/:id/history

Get last 7 days of tracking history and current streak.

Response:

{
  "success": true,
  "message": "Success",
  "data": {
    "history": [
      {
        "date": "2025-01-01",
        "completed": true
      },
      {
        "date": "2025-01-02",
        "completed": false
      },
      ...
    ],
    "streak": 5
  }
}

Error Responses

All errors follow this format:

{
  "success": false,
  "message": "Error message",
  "errors": [...]
}

Common status codes:

• 400: Bad Request (validation errors)
• 401: Unauthorized (invalid/missing token)
• 404: Not Found
• 429: Too Many Requests (rate limit exceeded)
• 500: Internal Server Error

Database Schema

User

• id (UUID)
• name
• email (unique)
• password (hashed)
• createdAt
• updatedAt

Habit

• id (UUID)
• title
• description
• frequency (daily/weekly)
• tags (array)
• reminderTime
• userId (foreign key)
• createdAt
• updatedAt

HabitLog

• id (UUID)
• habitId (foreign key)
• date (unique per habit)
• completedAt
• Unique constraint: (habitId, date)

Development Tools

Prisma Studio

View and edit your database:

pnpm prisma:studio

Rate Limiting

The API is rate-limited to 100 requests per hour per IP address.

License

ISC