Build and preview HTML, CSS, and JavaScript online with a fast browser-based web playground.
Web Lab
HTML, CSS, and JS in one workspace
The Mentrily online HTML editor lets you write HTML, CSS, and JavaScript side by side and see a live preview instantly. It is a fast way to prototype layouts, test snippets, and learn front-end development without setting up a local project.
Everything runs in your browser — no downloads, no configuration, and no account required to start. When you are ready, sign up free to save your work or turn it into course material.
Yes. The Mentrily HTML editor is completely free. You can write HTML, CSS, and JavaScript and preview the result instantly without creating an account.
No. Everything runs directly in your browser. There is nothing to download or configure — open the page and start coding.
Yes. The editor renders a live preview of your page as you type, so you can experiment with layouts, styles, and scripts and see the result immediately.
Yes. Mentrily is built for educators — you can create full courses and exams with web project questions, share them with learners, and track progress from one dashboard.
Mentrily supports 30+ languages. Jump straight into another playground: