How to Use API Endpoints in JavaScript: A Practical Tutorial

APIs power almost every modern web app, and JavaScript makes calling them simple. Using the built-in Fetch API, you can pull data from an endpoint, send new data, and handle errors — no extra libraries required.

Making a GET Request

A GET request retrieves data from a server. Call fetch() with the endpoint URL, then convert the response body to JSON:

const res = await fetch('https://api.example.com/users');
const users = await res.json();

Sending Data with POST

POST requests create or update resources. Pass an options object with the method, headers, and body:

fetch(url, { method: 'POST', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify({ name: 'Ada' }) });

Checking Status and Handling Errors

Important: fetch() only rejects on network failure, not on 404 or 500 responses. Always verify the request succeeded:

• Check res.ok before parsing the body.
• Wrap calls in try...catch with async/await.
• Show a fallback message in your UI on failure.

Conclusion

Start with a public test API, practice GET and POST calls, and add error handling early. That foundation covers the vast majority of real-world integrations.