JavaScript Fetch API Tutorial — GET, POST & Error Handling

Use fetch() to call REST APIs in JavaScript. JSON parsing, headers, POST bodies, and CORS basics.

Using fetch() for HTTP Requests

fetch is the modern browser API for HTTP requests. Every full-stack app uses it — or libraries built on top of it like axios.

Why JavaScript fetch API Matters

fetch is the browser-native way to load JSON, submit forms, and integrate third-party APIs without extra libraries.

Always check res.ok — fetch resolves on HTTP 404; only network failures reject the Promise.

JavaScript fetch API — Key Ideas You Must Know

fetch(url) returns a Promise
res.ok and res.status checks
await res.json() for JSON bodies
POST with method, headers, body
CORS is a browser security feature

JavaScript fetch API Code Example

JAVASCRIPT

const res = await fetch('/api/data', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({ name: 'Sturdee' })
});

Practice JavaScript fetch API with Free Lessons

Complete the fetch lesson on Sturdee and connect to a public API.

Tip: Free interactive lesson: /tutorials/javascript/javascript_fetch — practice JavaScript fetch API with runnable code on Sturdee.

JavaScript Fetch API Tutorial — FAQ

Frequently Asked Questions

fetch vs axios?+

fetch is built-in. axios adds interceptors and nicer defaults — both are fine.