Introduction to Web APIs

A Web API is a set of rules and protocols that allows different software applications to communicate over the internet. Think of it as a waiter in a restaurant - you make a request, and the API delivers the response.

Key characteristics of Web APIs:

• Use HTTP/HTTPS protocols
• Return data in structured formats (JSON, XML)
• Follow REST or GraphQL patterns
• Require authentication for secure endpoints

HTTP methods define the type of operation you want to perform:

1// GET - Retrieve data
2fetch('https://api.example.com/users')
3  .then(response => response.json())
4  .then(data => console.log(data));
5
6// POST - Create new data
7fetch('https://api.example.com/users', {
8  method: 'POST',
9  headers: {
10    'Content-Type': 'application/json'
11  },
12  body: JSON.stringify({
13    name: 'John Doe',
14    email: '[email protected]'
15  })
16});

Common HTTP methods:

• GET: Retrieve data
• POST: Create new resource
• PUT: Update existing resource
• DELETE: Remove resource

APIs typically return data in JSON format with status codes:

1// Example API response
2{
3  "status": "success",
4  "data": {
5    "id": 1,
6    "name": "John Doe",
7    "email": "[email protected]"
8  },
9  "message": "User retrieved successfully"
10}

Common HTTP status codes:

• 200: Success
• 201: Created
• 400: Bad Request
• 401: Unauthorized
• 404: Not Found
• 500: Server Error