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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430 challenges matching your filters
Clear topic filter- Multiple ChoiceIntermediate
[Security] Stored Inject scripts into pages
qasecuritysecurityqa - Multiple ChoiceIntermediate
[Security] Reflected Inject scripts into pages
qasecuritysecurityqa - Multiple ChoiceIntermediate
[Security] DOM-based Inject scripts into pages
qasecuritysecurityqa - Multiple ChoiceIntermediate
[Security] CSP Inject scripts into pages
qasecuritysecurityqa - Multiple ChoiceIntermediate
[Security] HttpOnly Inject scripts into pages
qasecuritysecurityqa - Multiple ChoiceIntermediate
[SQL] Readability WITH clause for readability
qasqlsqlqa - Multiple ChoiceIntermediate
[SQL] Recursive WITH clause for readability
qasqlsqlqa - Multiple ChoiceIntermediate
[SQL] Multiple WITH clause for readability
qasqlsqlqa - Multiple ChoiceIntermediate
[SQL] Materialized WITH clause for readability
qasqlsqlqa - Multiple ChoiceIntermediate
[SQL] Chained WITH clause for readability
qasqlsqlqa - Multiple ChoiceIntermediate
[SQL] B-tree Speed up queries via B-tree/hash
qasqlsqlqa - Multiple ChoiceIntermediate
[SQL] Covering Speed up queries via B-tree/hash
qasqlsqlqa - Multiple ChoiceIntermediate
[SQL] FK index Speed up queries via B-tree/hash
qasqlsqlqa - Multiple ChoiceIntermediate
[SQL] Partial Speed up queries via B-tree/hash
qasqlsqlqa - Multiple ChoiceIntermediate
[SQL] GIN/GiST Speed up queries via B-tree/hash
qasqlsqlqa - Multiple ChoiceIntermediate
[SQL] 1NF Reduce redundancy
qasqlsqlqa - Multiple ChoiceIntermediate
[SQL] 2NF Reduce redundancy
qasqlsqlqa - Multiple ChoiceIntermediate
[SQL] 3NF Reduce redundancy
qasqlsqlqa - Multiple ChoiceIntermediate
[SQL] BCNF Reduce redundancy
qasqlsqlqa - Multiple ChoiceIntermediate
[SQL] Denormalize Reduce redundancy
qasqlsqlqa - Multiple ChoiceIntermediate
[System Design] Round robin Distribute traffic
qasys-designsys-designqa - Multiple ChoiceIntermediate
[System Design] Least connections Distribute traffic
qasys-designsys-designqa - Multiple ChoiceIntermediate
[System Design] L4 vs L7 Distribute traffic
qasys-designsys-designqa - Multiple ChoiceIntermediate
[System Design] Health check Distribute traffic
qasys-designsys-designqa - Multiple ChoiceIntermediate
[System Design] Sticky sessions Distribute traffic
qasys-designsys-designqa - Multiple ChoiceIntermediate
[Testing] Line Code execution measurement
qatestingtestingqa - Multiple ChoiceIntermediate
[Testing] Branch Code execution measurement
qatestingtestingqa - Multiple ChoiceIntermediate
[Testing] Mutation Code execution measurement
qatestingtestingqa - Multiple ChoiceIntermediate
[Testing] 80% myth Code execution measurement
qatestingtestingqa - Multiple ChoiceIntermediate
[Testing] Threshold CI Code execution measurement
qatestingtestingqa - Multiple ChoiceIntermediate
[Testing] Test database Test cross-component interaction
qatestingtestingqa - Multiple ChoiceIntermediate
[Testing] Testcontainers Test cross-component interaction
qatestingtestingqa - Multiple ChoiceIntermediate
[Testing] Contract testing Test cross-component interaction
qatestingtestingqa - Multiple ChoiceIntermediate
[Testing] Seed data Test cross-component interaction
qatestingtestingqa - Multiple ChoiceIntermediate
[Testing] Teardown Test cross-component interaction
qatestingtestingqa - Multiple ChoiceIntermediate
[Testing] Function mock Simulate dependencies
qatestingtestingqa - Multiple ChoiceIntermediate
[Testing] Module mock Simulate dependencies
qatestingtestingqa - Multiple ChoiceIntermediate
[Testing] Spy Simulate dependencies
qatestingtestingqa - Multiple ChoiceIntermediate
[Testing] Partial mock Simulate dependencies
qatestingtestingqa - Multiple ChoiceIntermediate
[Testing] Reset Simulate dependencies
qatestingtestingqa - Multiple ChoiceIntermediate
[Testing] Jest Compare against stored output
qatestingtestingqa - Multiple ChoiceIntermediate
[Testing] Update flow Compare against stored output
qatestingtestingqa - Multiple ChoiceIntermediate
[Testing] Version control Compare against stored output
qatestingtestingqa - Multiple ChoiceIntermediate
[Testing] Regression Compare against stored output
qatestingtestingqa - Multiple ChoiceIntermediate
[Testing] Inline Compare against stored output
qatestingtestingqa - Multiple ChoiceIntermediate
[Testing] Red Red-Green-Refactor
qatestingtestingqa - Multiple ChoiceIntermediate
[Testing] Green Red-Green-Refactor
qatestingtestingqa - Multiple ChoiceIntermediate
[Testing] Refactor Red-Green-Refactor
qatestingtestingqa - Multiple ChoiceIntermediate
[Testing] Baby steps Red-Green-Refactor
qatestingtestingqa - Multiple ChoiceIntermediate
[Testing] Triangulation Red-Green-Refactor
qatestingtestingqa - Multiple ChoiceIntermediate
[TypeScript] Identity Type parameters
qatypescripttypescriptqa - Multiple ChoiceIntermediate
[TypeScript] Constraints Type parameters
qatypescripttypescriptqa - Multiple ChoiceIntermediate
[TypeScript] Defaults Type parameters
qatypescripttypescriptqa - Multiple ChoiceIntermediate
[TypeScript] Multiple Type parameters
qatypescripttypescriptqa - Multiple ChoiceIntermediate
[TypeScript] Conditional Type parameters
qatypescripttypescriptqa - Multiple ChoiceIntermediate
[TypeScript] Union | Type combinators
qatypescripttypescriptqa - Multiple ChoiceIntermediate
[TypeScript] Intersection & Type combinators
qatypescripttypescriptqa - Multiple ChoiceIntermediate
[TypeScript] Discriminated union Type combinators
qatypescripttypescriptqa - Multiple ChoiceIntermediate
[TypeScript] Never Type combinators
qatypescripttypescriptqa - Multiple ChoiceIntermediate
[TypeScript] Exhaustive Type combinators
qatypescripttypescriptqa
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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.