Challenge Library
Coding Challenges
5,893 curated questions across every arena — browse by topic, then jump into a live 2-minute battle to put them to the test.
Filter by type
Filter by difficulty
Popular topics
5,893 challenges total
- Multiple ChoiceIntermediate
CSS Grid vs Flexbox
frontendintermediate - Multiple ChoiceIntermediate
React useEffect
frontendintermediate - Multiple ChoiceIntermediate
Webpack entry
frontendintermediate - Multiple ChoiceIntermediate
CSS :nth-child
frontendintermediate - Multiple ChoiceHard
Browser rendering
frontendhard - Multiple ChoiceIntermediate
useCallback
frontendintermediate - Multiple ChoiceIntermediate
SSR vs CSR
frontendintermediate - Multiple ChoiceIntermediate
CSS Grid minmax
frontendintermediate - Multiple ChoiceBeginner
HTML5 semantics SEO
frontendbeginner - Multiple ChoiceIntermediate
Event loop browser
frontendintermediate - Multiple ChoiceIntermediate
CSS specificity weight
frontendintermediate - Multiple ChoiceIntermediate
useRef hook
frontendintermediate - Multiple ChoiceIntermediate
CSS custom props scope
frontendintermediate - Multiple ChoiceIntermediate
Responsive srcset
frontendintermediate - Multiple ChoiceIntermediate
Virtual DOM
frontendintermediate - Multiple ChoiceHard
CSS isolation
frontendhard - Multiple ChoiceIntermediate
TypeScript interfaces
frontendintermediate - Multiple ChoiceHard
CSS backdrop-filter
frontendhard - Multiple ChoiceIntermediate
PWA criteria
frontendintermediate - Multiple ChoiceIntermediate
CSS scroll-behavior
frontendintermediate - Multiple ChoiceBeginner
JSX syntax
frontendbeginner - Multiple ChoiceIntermediate
Web Vitals FID
frontendintermediate - Multiple ChoiceHard
CSS containment
frontendhard - Multiple ChoiceIntermediate
React Suspense
frontendintermediate - Multiple ChoiceHard
CSS shape-outside
frontendhard - Multiple ChoiceIntermediate
IndexedDB vs localStorage
frontendintermediate - Multiple ChoiceIntermediate
CSS color-scheme
frontendintermediate - Multiple ChoiceHard
View Transitions API
frontendhard - Multiple ChoiceIntermediate
CSS math functions
frontendintermediate - Multiple ChoiceHard
useDeferredValue
frontendhard - Multiple ChoiceHard
CSS overscroll-behavior
frontendhard - Multiple ChoiceHard
Import maps
frontendhard - Multiple ChoiceHard
CSS text-wrap balance
frontendhard - Multiple ChoiceHard
Web Locks API
frontendhard - Multiple ChoiceHard
CSS nesting
frontendhard - Multiple ChoiceHard
Scroll-driven animations
frontendhard - Multiple ChoiceHard
CSS :has() selector
frontendhard - Multiple ChoiceHard
Popover API
frontendhard - Multiple ChoiceHard
CSS anchor positioning
frontendhard - Multiple ChoiceHard
Declarative Shadow DOM
frontendhard - Multiple ChoiceHard
CSS font-palette
frontendhard - Multiple ChoiceHard
Navigation API
frontendhard - Multiple ChoiceHard
Fetch Priority API
frontendhard - Multiple ChoiceHard
Storage API estimate
frontendhard - Multiple ChoiceHard
CSS layer specificity
frontendhard - Multiple ChoiceIntermediate
WebSocket vs SSE
frontendintermediate - Multiple ChoiceHard
CSS color-mix
frontendhard - Multiple ChoiceIntermediate
Permissions API
frontendintermediate - Multiple ChoiceHard
CSS container style queries
frontendhard - Multiple ChoiceIntermediate
Sanitizer API
frontendintermediate - Code AnalysisBeginner
Array every
frontendbeginner - Code AnalysisBeginner
Set uniqueness
frontendbeginner - Code AnalysisHard
Object.keys order
frontendhard - Code AnalysisIntermediate
FlatMap result
frontendintermediate - Code AnalysisBeginner
padStart
frontendbeginner - Code AnalysisIntermediate
Object.entries loop
frontendintermediate - Code AnalysisIntermediate
Array slice negative
frontendintermediate - Code AnalysisIntermediate
Promise finally
frontendintermediate - Code AnalysisBeginner
String includes
frontendbeginner - Code AnalysisIntermediate
Array sort default
frontendintermediate
Practice now, dominate the arena
Every challenge here is drawn from the live Code Royale pool. Review a question, then head to the arena to answer under pressure against a real opponent — 2-minute matches, Elo ranking, and badge tiers on the line.