Challenge Library
Coding Challenges
5,893 curated questions across every arena — browse by topic, then jump into a live 3-minute battle to put them to the test.
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1,300 challenges matching your filters
- Multiple ChoiceBeginner
CDC to search index consistency
searchcdcconsistency - Multiple ChoiceBeginner
Mobile push token lifecycle handling
push-notificationstoken-managementapns-fcm - Multiple ChoiceBeginner
[Testing] Jest Same test, multiple inputs
qatestingtestingqa - Multiple ChoiceBeginner
[Testing] Pytest Same test, multiple inputs
qatestingtestingqa - Multiple ChoiceBeginner
[Testing] DRY Same test, multiple inputs
qatestingtestingqa - Multiple ChoiceBeginner
[Testing] Table-driven Go Same test, multiple inputs
qatestingtestingqa - Multiple ChoiceBeginner
[Testing] Coverage boost Same test, multiple inputs
qatestingtestingqa - Multiple ChoiceBeginner
[Testing] AAA Test isolated units
qatestingtestingqa - Multiple ChoiceBeginner
[Testing] Pyramid Test isolated units
qatestingtestingqa - Multiple ChoiceBeginner
[Testing] Mock vs stub Test isolated units
qatestingtestingqa - Multiple ChoiceBeginner
[Testing] FIRST Test isolated units
qatestingtestingqa - Multiple ChoiceBeginner
[Testing] Test doubles Test isolated units
qatestingtestingqa - Multiple ChoiceBeginner
[TypeScript] Numeric Named constants
qatypescripttypescriptqa - Multiple ChoiceBeginner
[TypeScript] String Named constants
qatypescripttypescriptqa - Multiple ChoiceBeginner
[TypeScript] const enum Named constants
qatypescripttypescriptqa - Multiple ChoiceBeginner
[TypeScript] Reverse mapping Named constants
qatypescripttypescriptqa - Multiple ChoiceBeginner
[TypeScript] Ambient Named constants
qatypescripttypescriptqa - Multiple ChoiceBeginner
[Webpack] devServer Development experience
qawebpackwebpackqa - Multiple ChoiceBeginner
[Webpack] Proxy Development experience
qawebpackwebpackqa - Multiple ChoiceBeginner
[Webpack] HMR Development experience
qawebpackwebpackqa - Multiple ChoiceBeginner
[Webpack] Host/port Development experience
qawebpackwebpackqa - Multiple ChoiceBeginner
[Webpack] Watch Development experience
qawebpackwebpackqa - Multiple ChoiceBeginner
[Webpack] Entry Define build start and end
qawebpackwebpackqa - Multiple ChoiceBeginner
[Webpack] Output Define build start and end
qawebpackwebpackqa - Multiple ChoiceBeginner
[Webpack] Multiple entries Define build start and end
qawebpackwebpackqa - Multiple ChoiceBeginner
[Webpack] PublicPath Define build start and end
qawebpackwebpackqa - Multiple ChoiceBeginner
[Webpack] Hash in filename Define build start and end
qawebpackwebpackqa - Multiple ChoiceBeginner
API versioning: additive change
architectureapiversioningbackward-compatibility - Multiple ChoiceBeginner
Test pyramid rationale
architecturetestingtest-pyramid - Multiple ChoiceBeginner
Stub vs mock vs fake
architecturetestingtest-doubles - Multiple ChoiceBeginner
Dependency injection benefit
architecturetestingdi - Multiple ChoiceBeginner
ADRs purpose
architectureadrdocumentation - Multiple ChoiceBeginner
Cyclic dependencies harm
architecturemodularitydependencies - Multiple ChoiceBeginner
Package cohesion: CCP
architecturemodularitycohesion - Multiple ChoiceBeginner
Facade reduces coupling
architecturedesign-patternsfacade - Multiple ChoiceBeginner
Cross-cutting logging
architecturecross-cuttinglogging - Multiple ChoiceBeginner
Config as external concern
architectureconfigurationtwelve-factor - Multiple ChoiceBeginner
Composition over inheritance
architectureoopcomposition - Multiple ChoiceBeginner
Anti-corruption in practice
architecturedddacl - Multiple ChoiceBeginner
Port naming by role
architecturehexagonalnaming
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 — 3-minute matches, Elo ranking, and badge tiers on the line.