A secure, client-side playground for HTML, CSS, and JavaScript. Write code instantly without installing complex environments.
No sign-up required • Runs entirely in your browser
Everything you need for rapid frontend prototyping.
See your changes in real-time. Our lightweight execution engine renders HTML, CSS, and JS instantly as you type.
Your code never leaves your device. All execution happens client-side in your browser, ensuring maximum privacy.
Export your work as a standard ZIP file or upload existing projects to continue working anywhere, anytime.
Use our intelligent Monaco editor with syntax highlighting for HTML, CSS, and JS.
Click the "Run" button to compile your code within a sandboxed iframe immediately.
Finished? Download your entire project structure as a .zip file with one click.
Yes, Syntax Error is completely free to use for personal and educational purposes.
Currently, the initial load requires internet, but since the execution is client-side, it is very low bandwidth.
Yes, you can link to external CDNs (like Bootstrap, Tailwind, or jQuery) inside the HTML editor.