Build HTTP APIs with routing, middleware, validation, controllers, and error handling.
Lessons
Inspect request headers and set response headers deliberately.
Reading and Setting Headers is easiest to learn by reading the example, changing it, and observing the result.
import express from 'express';
const app = express();
app.use(express.json());
app.get('/api/lessons', (req, res) => {
res.json([{ slug: 'express-routing', title: 'Express Routing' }]);
});
app.post('/api/lessons', (req, res) => {
res.status(201).json({ created: true, title: req.body.title });
});
app.listen(process.env.PORT || 3000);Practice the Reading and Setting Headers example in a small scratch file, then explain what changed and why.
In accordance with Section 6 & Section 7 of the DPDP Act 2023, third-party analytics and marketing trackers are strictly gated behind your affirmative consent. You may withdraw consent at any time under Section 6(4).
Essential for session authentication (ci_session), Cross-Site Request Forgery security (csrf_cookie_name), and Cloudflare DDoS/bot prevention. Cannot be disabled.
Gated under DPDP Section 7. Allows Google Analytics 4 (Google Consent Mode v2) to measure aggregate, anonymized tool usage.
Enables browser local storage to preserve your theme selection (dark/light mode) and code editor layout between visits.
Used to display developer sponsorships and native tool partner notices.