REST APIs: What They Are and How to Use Them

What is an API?

• API = Application Programming Interface.
• It’s like a waiter in a restaurant: you (the client) place an order, the waiter (API) takes it to the kitchen (server), and brings the food (response) back to you.

2. What is REST?

• REST (Representational State Transfer) is a set of rules for building web APIs.
• REST APIs use HTTP methods (like GET, POST, PUT, DELETE) to interact with resources.
• Resources are usually represented as JSON objects.

3. Common HTTP Methods in REST APIs

• GET → Retrieve data (e.g., fetch a list of users).
• POST → Send new data (e.g., create a new account).
• PUT/PATCH → Update existing data (e.g., edit profile details).
• DELETE → Remove data (e.g., delete a comment).

4. Example of a REST API Request

GET https://api.example.com/users/1

Response:

{
  "id": 1,
  "name": "John Doe",
  "email": "john@example.com"
}

5. How to Use REST APIs

1. Find the API documentation (e.g., Twitter API, GitHub API).
2. Get an API key (if authentication is required).
3. Send requests using tools like:
   • Browser (for simple GET requests).
   • Postman (testing APIs).
   • Fetch in JavaScript: fetch("https://api.example.com/users") .then(response => response.json()) .then(data => console.log(data));
4. Handle responses → usually in JSON format.

6. Real-Life Examples of REST APIs

• Weather App → Fetch current weather data from an API.
• Social Media → Posting a tweet or fetching Instagram posts.
• E-commerce → Add to cart, checkout, get product details.