Build Blocks
Sharpen your frontend engineering skills with Build Blocks — bite-sized functional coding challenges designed for real-world scenarios. From custom React hooks to complex state management, practice solving practical problems directly in our in-browser IDE with live preview. Whether you’re preparing for interviews or leveling up your coding confidence, Build Blocks helps you go beyond UI design and master the logic that powers modern web apps.
Counter with Step
Build a counter that increments and decrements by a customizable step value.
Toggle Dark Mode
Implement a dark/light mode toggle using React state.
Custom useLocalStorage Hook
Create a custom React hook that syncs state with localStorage.
Character Counter
Display a live character counter for a text input with max length.
Password Visibility Toggle
Add a button to toggle password field visibility.
Search and Filter List
Build a search bar to filter through a list of items in real time.
Tabs Component
Create a tabbed interface that switches content on click.
Accordion Component
Implement an accordion that expands and collapses sections.
Basic Form Validation
Create a form with validation for required fields and email format.
Stopwatch
Create a stopwatch with start, pause, and reset functionality.