Master React Through Real-World Challenges
Write React and TypeScript in a full Monaco editor with IntelliSense, autocomplete, and optional Vim mode.
Run your code against a real Node + Jest server — the same setup you’d face in production and technical interviews.
Last challenges
Best practices
In a technical interview, solving the logic is only half the battle — reviewers also judge your code's quality. A todo list that works perfectly can still hide anti-patterns like derived state in effects, impure renders, or eager initializers that degrade performance. This challenge is different: instead of just checking that your code passes tests, the platform also runs ESLint with React best-practice rules and surfaces every violation. Fix the 3 lint warnings to prove you don't just make it work — you make it right.
dddSimple, transparent pricing
- 1Full access to 50+ challenges across all levels
- 2New challenges added every week
- 3Exclusive advanced topics: Redux, React 19, compound components
- 4View solutions and learn from working code
- 1Full access to 50+ challenges across all levels
- 2New challenges added every week
- 3Exclusive advanced topics: Redux, React 19, compound components
- 4View solutions and learn from working code
- 1Full access to 50+ challenges across all levels
- 2New challenges added every week
- 3Exclusive advanced topics: Redux, React 19, compound components
- 4View solutions and learn from working code
- 1Start solving free coding challenges
- 2All challenges include TypeScript and pre-styled layouts
- 3Code editor with optional Vim mode
- 4Run and test your code instantly in the browser