Banking Backend

A Django-based banking system that allows users to manage accounts, perform transactions (deposits, withdrawals, transfers), and track balances computed from transaction history.

Features

• ✅ User account management with authentication
• ✅ Real-time balance calculation from transaction history
• ✅ Secure money transfers between users
• ✅ Deposit and withdrawal operations
• ✅ Complete transaction audit trail
• ✅ Token-based authentication
• ✅ Admin panel for staff operations
• ✅ Historical balance queries (bonus feature)

Setup

1. Install dependencies:

pip install -r requirements.txt

2. Run migrations:

python manage.py migrate
python manage.py createsuperuser

3. Start server:

python manage.py runserver

API Documentation

All endpoints except user creation and login require authentication. Include the token in the Authorization header:

Authorization: Token <your_token_here>

Authentication Endpoints

Create User

POST /users
Content-Type: application/json

{
  "username": "testuser",
  "email": "[email protected]",
  "password": "testpass123",
  "first_name": "Test",
  "last_name": "User"
}

Response:

{
  "id": 1,
  "username": "testuser",
  "email": "[email protected]",
  "first_name": "Test",
  "last_name": "User",
  "date_joined": "2025-08-16T10:30:00Z",
  "is_active": true
}

Login

POST /auth/login
Content-Type: application/json

{
  "username": "testuser",
  "password": "testpass123"
}

Response:

{
  "token": "abc123def456...",
  "user_id": 1,
  "username": "testuser",
  "message": "Login successful"
}

Logout

POST /auth/logout
Authorization: Token abc123def456...

Response:

{
  "message": "Successfully logged out"
}

Account Management

Create Account

POST /accounts
Authorization: Token abc123def456...
Content-Type: application/json

{
  "bank_name": "Savings Bank",
  "branch": "Main Branch"
}

Response:

{
  "id": 1,
  "bank_name": "Savings Bank",
  "branch": "Main Branch",
  "user_id": 1,
  "username": "testuser",
  "balance": "0.00",
  "created_at": "2025-08-16T10:30:00Z"
}

Get Account Details

GET /accounts/{account_id}
Authorization: Token abc123def456...

Response:

{
  "name": "Test User",
  "bank": "Savings Bank",
  "branch": "Main Branch",
  "balance": "1000.00"
}

List All Accounts

GET /accounts/all
Authorization: Token abc123def456...

Response:

[
  {
    "id": 1,
    "user_id": 1,
    "bank_name": "Savings Bank",
    "branch": "Main Branch",
    "created_at": "2025-08-16T10:30:00Z"
  }
]

Get Account Balance

GET /accounts/{account_id}/balance
Authorization: Token abc123def456...

Response:

{
  "balance": "1000.00"
}

Transaction Operations

Deposit Money

POST /transactions/deposit
Authorization: Token abc123def456...
Content-Type: application/json

{
  "account_id": 1,
  "amount": "100.00",
  "note": "Initial deposit"
}

Response:

{
  "id": 1,
  "account_id": 1,
  "amount": "100.00",
  "transaction_type": "DEPOSIT",
  "status": "SUCCESS",
  "note": "Initial deposit",
  "created_at": "2025-08-16T10:30:00Z",
  "new_balance": "100.00"
}

Withdraw Money

POST /transactions/withdraw
Authorization: Token abc123def456...
Content-Type: application/json

{
  "account_id": 1,
  "amount": "50.00",
  "note": "ATM withdrawal"
}

Response:

{
  "id": 2,
  "account_id": 1,
  "amount": "50.00",
  "transaction_type": "WITHDRAWAL",
  "status": "SUCCESS",
  "note": "ATM withdrawal",
  "created_at": "2025-08-16T10:35:00Z",
  "new_balance": "50.00"
}

Transfer Money

POST /transactions/transfer
Authorization: Token abc123def456...
Content-Type: application/json

{
  "from_account_id": 1,
  "to_account_id": 2,
  "amount": "25.00",
  "note": "Payment for services"
}

Response:

{
  "debit_transaction": {
    "id": 3,
    "account_id": 1,
    "amount": "25.00",
    "transaction_type": "TRANSFER",
    "status": "SUCCESS",
    "note": "Transfer to user2: Payment for services",
    "created_at": "2025-08-16T10:40:00Z"
  },
  "credit_transaction": {
    "id": 4,
    "account_id": 2,
    "amount": "25.00",
    "transaction_type": "TRANSFER",
    "status": "SUCCESS",
    "note": "Transfer from testuser: Payment for services",
    "created_at": "2025-08-16T10:40:00Z"
  },
  "from_account_balance": "25.00",
  "to_account_balance": "25.00",
  "transfer_amount": "25.00"
}

Get Transaction History

GET /transactions/{account_id}
Authorization: Token abc123def456...

Response:

[
  {
    "id": 1,
    "account_id": 1,
    "amount": "100.00",
    "transaction_type": "DEPOSIT",
    "status": "SUCCESS",
    "note": "Initial deposit",
    "created_at": "2025-08-16T10:30:00Z"
  }
]

Error Responses

All endpoints return consistent error responses:

{
  "error": "Error message description"
}

Common HTTP status codes:

• 400 - Bad Request (validation errors, insufficient balance)
• 401 - Unauthorized (missing or invalid token)
• 404 - Not Found (account/user doesn't exist)
• 500 - Internal Server Error

Example Usage Flow

1. Create a user account:

curl -X POST http://localhost:8000/users \
  -H "Content-Type: application/json" \
  -d '{"username": "alice", "email": "[email protected]", "password": "pass123", "first_name": "Alice", "last_name": "Smith"}'

2. Login to get token:

curl -X POST http://localhost:8000/auth/login \
  -H "Content-Type: application/json" \
  -d '{"username": "alice", "password": "pass123"}'

3. Create bank account:

curl -X POST http://localhost:8000/accounts \
  -H "Authorization: Token YOUR_TOKEN_HERE" \
  -H "Content-Type: application/json" \
  -d '{"bank_name": "My Bank", "branch": "Downtown"}'

4. Make a deposit:

curl -X POST http://localhost:8000/transactions/deposit \
  -H "Authorization: Token YOUR_TOKEN_HERE" \
  -H "Content-Type: application/json" \
  -d '{"account_id": 1, "amount": "1000.00", "note": "Initial deposit"}'

5. Check balance:

curl -X GET http://localhost:8000/accounts/1/balance \
  -H "Authorization: Token YOUR_TOKEN_HERE"