The Must-Solve 150.
Every question is a real implementation, debugging or architecture task. Work through the levels in order, or jump straight to what your next interview needs.
10 of 150 questions
Medium
75 questions, 25–45 minutes each
Implement, then defend your edge cases, performance and tests.
UI machine coding
Accessible, keyboard-friendly widgets built under interview time pressure.
- 76Build an accessible accordion with keyboard navigation
- 77Build a typeahead/autocomplete with caching and keyboard supportFree
- 78Build a nested file explorer with add, rename, and delete
- 79Build a sortable and filterable data table
- 80Build a drag-and-drop Kanban board
- 81Build a nested comments component with threaded replies
- 82Build a progress bar system supporting multiple queued animations
- 83Build a multi-select dropdown with search and tags
- 84Build a tree view with expand, collapse, and checkbox selection
- 85Build a date picker with keyboard navigation and disabled dates