Interactive HTML, CSS, and JavaScript that render the moment you hit Run — then go further than any tutorial and ship a real edge app with Cloudflare Workers, D1, and KV in an in-browser Worker simulator. Every challenge auto-graded. No setup, no install.
No credit card for the free tier · three full tracks free forever
.card { text-align: center; padding: 22px; } .card h3 { color: #6366f1; } button { background: #6366f1; border-radius: 8px; }
Most "courses" are videos you watch. Webinator is a live sandbox next to a written explanation, with a graded challenge that runs your actual code.
Your HTML, CSS, and JavaScript render in a sandboxed iframe the moment you hit Run. Change a color, watch it move. No build step, no server.
Challenges check the real computed styles, the real DOM, the real console output — not string matching. Pass to mark complete; hints appear gradually.
The Stack track runs your real Cloudflare Worker — export default { fetch } — against a mock request, a live SQLite database (D1), and KV. Build a backend with zero deploys.
The same Monaco editor that powers VS Code — syntax highlighting, multi-cursor, keyboard shortcuts. It feels like the real thing because it is.
Finish a track, download a personalized PDF certificate. Earn badges at every milestone and keep a streak going.
A no-rules scratchpad with a live preview, console, and the Worker simulator. Prototype a page or a tiny API and share it by link.
Start anywhere. The fundamentals are free; the JavaScript and edge-stack tracks are where it gets serious.
Make your first page light up — headings, lists, links, color. Jargon-free, ages 7+.
FREEHTML structure: headings, lists, links, images, forms — build real pages from scratch.
FREEBox model, flexbox, grid, responsive layout, transitions — graded on rendered styles.
PROVariables → the DOM → events → fetch → async. Real interactivity, auto-graded as it runs.
PROCloudflare Workers, D1, KV, email, and auth — build a real edge backend in the simulator.
Every lesson follows the same loop. The skill comes from the doing — not the watching.
Tight, plain-English, with code examples. One idea per lesson.
A real Monaco editor with starter code. Hit Run and your work renders live beside it.
Hidden tests run against the actual result — computed styles, the DOM, the HTTP response. Pass/fail with helpful messages.
Three progressive hints. The solution unlocks after a few attempts — earn it the right way.
Kids, Beginner, and CSS are free forever. Pro unlocks JavaScript, The Stack, and the Playground.
No. Everything runs in your browser — your HTML/CSS/JS render in a sandboxed iframe, and the Worker simulator runs a real SQLite database (sql.js) locally. There's nothing to download and no server to manage.
Real. You write an actual Cloudflare Worker — export default { async fetch(request, env) } — and we run it against a mock Request, a live in-memory SQLite database exposed through the real D1 API, a KV store, and a service binding for email. The code you write is the code you'd deploy.
By running your code. CSS lessons check the real computed styles; JavaScript lessons check the DOM, return values, or console output; Worker lessons check the HTTP response, the database, and KV. No brittle string matching.
Anytime, in one click. Open the user menu → Manage subscription → cancel. You keep Pro access until the end of the period you've paid for. See our refund policy.
Always. Your progress, streak, and earned badges/certificates stay tied to your account regardless of plan.