How to Use the API – Base URL and Data Format

Once the application is running, all requests target a single base URL, and both requests and responses use JSON. This section explains how to construct URLs, configure the Postman collection, and format payloads.

Base URL 🌐

All endpoints live under a common base address.

• Default local address

By default, the Flask app listens on port 5000.

Base URL:

  http://localhost:5000

(configured in app.run(port=5000, debug=True))

• Postman collection variable

The provided Postman collection uses a {{url}} variable.

• Update {{url}} once to switch environments.
• Example request entry in Python Rest API.postman_collection.json:

    "url": {
      "raw": "{{url}}/books",
      "host": ["{{url}}"],
      "path": ["books"]
    }

{
    "title": "Postman Tip",
    "content": "Use the {{url}} variable to switch hosts and ports in one place."
}

Data Format 📄

Every endpoint expects JSON input and returns JSON output.

Request Payload

• Content-Type: application/json
• Structure: Depends on endpoint (see individual endpoint docs).
• Example – Creating a user:

  curl -X POST {{url}}/register \
    -H "Content-Type: application/json" \
    -d '{
      "username": "alice",
      "password": "secret123"
    }'

Response Payload

• Content-Type: application/json
• Standard envelope: Objects or error messages.
• Example – Successful registration:

  {
    "message": "User created successfully."
  }

Common Headers

* Only protected endpoints require the Authorization header.

With the http://localhost:5000 base URL and JSON formatting rules in place, you can seamlessly test and consume all CRUD and authentication endpoints of the library API.