Expense Tracker 💳

This is a RESTful backend API built with Node.js and Express.js that provides secure user management and transaction tracking for an expense-tracking application. It uses MongoDB for data storage, supports authenticated access, and provides flexible APIs for creating, reading, updating, and deleting user transaction data.

The API is fully documented using OpenAPI (Swagger), providing an interactive way to explore and test the endpoints.

Live Demo: https://api-expence-tacker.onrender.com
Live API Documentation: https://api-expence-tacker.onrender.com/api-docs

Features⚡

• Expense Management: Full CRUD operations to add, edit, delete, and fetch user expenses with structured fields like title, amount, category, and date.
• Secure User Authentication: JWT-based authentication with password to ensure safe login and protected access to all transaction routes.
• Advanced Filtering:
  • Filter expenses by category, date, or amount range.
• Pagination: Efficiently load large sets of expense data using page and limit query parameters.
• User-Scoped Data: Each user only accesses their own expense records, enforced via JWT validation and user-bound queries.
• API Documentation: Interactive API documentation powered by Swagger (OpenAPI) is available at the /api-docs endpoint.

Tech Stack 🚀

Technology	Description
Node.js	JavaScript runtime environment
Express.js	Web framework for building the REST API
MongoDB	NoSQL database to store application data
Mongoose	ODM library for MongoDB and Node.js
JSON Web Token (JWT)	For securing endpoints and managing sessions
dotenv	For managing environment variables
Postman	API endpoints testing
Swagger UI	For generating interactive API documentation

Getting Started ⚙️

To get a local copy up and running, follow these simple steps.

Prerequisites

• Node.js (v20.19.0 or higher)
• npm (Node Package Manager)
• MongoDB instance (local or cloud-based service something like MongoDB Atlas)

Installation & Setup 📦

1. Clone the repository:

   git clone https://github.com/03-Bunny-06/expence-tacker.git

2. Navigate to the server directory:

   cd expence-tacker/server

3. Install dependencies:

   npm install

4. Create an environment file: Create a .env file in the server directory and add your environment variables.

   # .env
   DATABASE_URL="your_mongodb_connection_string"
   PORT=8080

5. Start the server:

   npm start

The server will start on the port specified in your .env file (or 8080 by default). You can access the API documentation at http://localhost:8080/api-docs.

Data Models 🗂️

User Schema

{
    userId: {
        type: String,
        required: true,
        unique: true
    },
    email: {
        type: String,
        required: true,
        unique: true
    },
    password: {
        type: String,
        required: true
    }
}

Transaction Schema

const categories = ["Food", "Transport", "Rent", "Utilities", "Entertainment", "Shopping", "Income", "Miscellaneous","Other"];
{
    userId: {
        type: String,
        required: true
    },
    title: {
        type: String,
        required: true
    },
    amount: {
        type: Number,
        required: true
    },
    category: {
        type: String,
        enum: categories,
        required: true,
        default: "Other"
    },
    date: {
        type: Date,
        required: true,
        default: Date.now
    },
    notes: {
        type: String,
        trim: true,
        maxLength: 150
    }
}

API Endpoints 🔗

The API is structured into two main routes that handles: User and Transaction. User endpoint is for handling registering and logging in users. Transaction endpoint is for managing transactions.

User Routes (/user)

Method	Endpoint	Description	Authentication
POST	/user/register	Registers a new user.	Open
POST	/user/login	Logs in an existing user.	Open

Transactions Routes (/user/transactions)

Method	Endpoint	Description	Authentication
POST	/user/transactions/create	Creates a new transaction.	User
PUT	/user/transactions/edit/:id	Updates a transaction with ID.	User
DELETE	/user/transactions/delete/:id	Deletes a transaction with ID.	User
GET	/user/transactions	Fetches all transaction details with filtering & pagination.	User
GET	/user/transactions/analytics	Fetches the analytical data.	User

API Testing with Postman 🧪

• The repository includes a collection.json file exported from Postman.
• It contains structured test folders covering authentication, CRUD operations, protected routes, and error cases.
• Developers can import this collection directly into Postman to run predefined requests against the API.

Import Instructions

1. Open Postman
2. Click Import
3. Load the collection.json file
4. Start testing the endpoints