ClearFrontend is a free, open-source place to practice JavaScript. You work through short coding puzzles, try your own solution, and see right away whether it passes—so you can learn by doing and sharpen your skills at your own pace.
- A growing set of challenges you can browse and solve in the browser
- Quick feedback when you run your code against each challenge’s checks
- A simple way to share a snippet of your work with others when you want feedback or bragging rights
- Welcomes ideas and fixes from the community
Disclaimer: To enhance the vision and usage, we are shadowing our user's interactions. This is solely performed to serve you better
If you are interested in contributing—bug fixes, improvements, or new challenges—see the Contributing Guide.
File a bug report or feature request using the New Issues page.
docs/architecture.md— system design and data flowsdocs/security_ai.md— isolated-vm security modelAGENTS.md/CLAUDE.md— identical AI assistant playbooks (Cursor, Claude Code, Codex, and similar): project conventions, challenge authoring, and server-side rules. Human contributors often use them as the authoritative checklist too.
This repository is MIT licensed.