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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1,033 challenges matching your filters

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Multiple ChoiceHard
[C Language] const volatile Prevent compiler optimization
qaccqa
Multiple ChoiceHard
[CI/CD] Blue-green Ship to production
qacicdcicdqa
Multiple ChoiceHard
[CI/CD] Canary Ship to production
qacicdcicdqa
Multiple ChoiceHard
[CI/CD] Rolling Ship to production
qacicdcicdqa
Multiple ChoiceHard
[CI/CD] Feature flags Ship to production
qacicdcicdqa
Multiple ChoiceHard
[CI/CD] Rollback Ship to production
qacicdcicdqa
Multiple ChoiceIntermediate
[CI/CD] BuildKit Container-based builds
qacicdcicdqa
Multiple ChoiceIntermediate
[CI/CD] Layer caching Container-based builds
qacicdcicdqa
Multiple ChoiceIntermediate
[CI/CD] Multi-platform Container-based builds
qacicdcicdqa
Multiple ChoiceIntermediate
[CI/CD] Push to registry Container-based builds
qacicdcicdqa
Multiple ChoiceIntermediate
[CI/CD] Git SHA tag Container-based builds
qacicdcicdqa
Multiple ChoiceIntermediate
[CI/CD] Parity Dev, staging, production
qacicdcicdqa
Multiple ChoiceIntermediate
[CI/CD] Config Dev, staging, production
qacicdcicdqa
Multiple ChoiceIntermediate
[CI/CD] Secrets Dev, staging, production
qacicdcicdqa
Multiple ChoiceIntermediate
[CI/CD] Promotion Dev, staging, production
qacicdcicdqa
Multiple ChoiceIntermediate
[CI/CD] Ephemeral Dev, staging, production
qacicdcicdqa
Multiple ChoiceIntermediate
[CI/CD] workflow GitHub's CI/CD
qacicdcicdqa
Multiple ChoiceIntermediate
[CI/CD] jobs/runner GitHub's CI/CD
qacicdcicdqa
Multiple ChoiceIntermediate
[CI/CD] actions/checkout GitHub's CI/CD
qacicdcicdqa
Multiple ChoiceIntermediate
[CI/CD] Secrets GitHub's CI/CD
qacicdcicdqa
Multiple ChoiceIntermediate
[CI/CD] Matrix strategy GitHub's CI/CD
qacicdcicdqa
Multiple ChoiceBeginner
[CI/CD] Stages Automated workflow steps
qacicdcicdqa
Multiple ChoiceBeginner
[CI/CD] Triggers Automated workflow steps
qacicdcicdqa
Multiple ChoiceBeginner
[CI/CD] YAML config Automated workflow steps
qacicdcicdqa
Multiple ChoiceBeginner
[CI/CD] Artifacts Automated workflow steps
qacicdcicdqa
Multiple ChoiceBeginner
[CI/CD] CI vs CD Automated workflow steps
qacicdcicdqa
Multiple ChoiceIntermediate
[CI/CD] Unit first Automated quality gates
qacicdcicdqa
Multiple ChoiceIntermediate
[CI/CD] Integration Automated quality gates
qacicdcicdqa
Multiple ChoiceIntermediate
[CI/CD] E2E Automated quality gates
qacicdcicdqa
Multiple ChoiceIntermediate
[CI/CD] Flaky handling Automated quality gates
qacicdcicdqa
Multiple ChoiceIntermediate
[CI/CD] Coverage reports Automated quality gates
qacicdcicdqa
Multiple ChoiceIntermediate
[CSS] @keyframes Keyframes and transitions
qacsscssqa
Multiple ChoiceIntermediate
[CSS] transition Keyframes and transitions
qacsscssqa
Multiple ChoiceIntermediate
[CSS] easing Keyframes and transitions
qacsscssqa
Multiple ChoiceIntermediate
[CSS] fill-mode Keyframes and transitions
qacsscssqa
Multiple ChoiceIntermediate
[CSS] will-change Keyframes and transitions
qacsscssqa
Multiple ChoiceBeginner
[CSS] Content Content, padding, border, margin
qacsscssqa
Multiple ChoiceBeginner
[CSS] Padding Content, padding, border, margin
qacsscssqa
Multiple ChoiceBeginner
[CSS] Border Content, padding, border, margin
qacsscssqa
Multiple ChoiceBeginner
[CSS] Margin Content, padding, border, margin
qacsscssqa
Multiple ChoiceBeginner
[CSS] justify-content One-dimensional layout
qacsscssqa
Multiple ChoiceBeginner
[CSS] align-items One-dimensional layout
qacsscssqa
Multiple ChoiceBeginner
[CSS] gap One-dimensional layout
qacsscssqa
Multiple ChoiceBeginner
[CSS] flex-wrap One-dimensional layout
qacsscssqa
Multiple ChoiceBeginner
[CSS] flex-direction One-dimensional layout
qacsscssqa
Multiple ChoiceIntermediate
[CSS] grid-template-columns Two-dimensional layout
qacsscssqa
Multiple ChoiceIntermediate
[CSS] grid-template-areas Two-dimensional layout
qacsscssqa
Multiple ChoiceIntermediate
[CSS] auto-fill Two-dimensional layout
qacsscssqa
Multiple ChoiceIntermediate
[CSS] place-items Two-dimensional layout
qacsscssqa
Multiple ChoiceIntermediate
[CSS] subgrid Two-dimensional layout
qacsscssqa
Multiple ChoiceBeginner
[CSS] relative Where element renders
qacsscssqa
Multiple ChoiceBeginner
[CSS] absolute Where element renders
qacsscssqa
Multiple ChoiceBeginner
[CSS] fixed Where element renders
qacsscssqa
Multiple ChoiceBeginner
[CSS] sticky Where element renders
qacsscssqa
Multiple ChoiceBeginner
[CSS] static Where element renders
qacsscssqa
Multiple ChoiceIntermediate
[CSS] Media queries Adapt to viewport
qacsscssqa
Multiple ChoiceIntermediate
[CSS] Container queries Adapt to viewport
qacsscssqa
Multiple ChoiceIntermediate
[CSS] clamp() Adapt to viewport
qacsscssqa
Multiple ChoiceIntermediate
[CSS] Viewport units Adapt to viewport
qacsscssqa
Multiple ChoiceIntermediate
[CSS] aspect-ratio Adapt to viewport
qacsscssqa

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.

Coding Challenges

[C Language] const volatile Prevent compiler optimization

[CI/CD] Blue-green Ship to production

[CI/CD] Canary Ship to production

[CI/CD] Rolling Ship to production

[CI/CD] Feature flags Ship to production

[CI/CD] Rollback Ship to production

[CI/CD] BuildKit Container-based builds

[CI/CD] Layer caching Container-based builds

[CI/CD] Multi-platform Container-based builds

[CI/CD] Push to registry Container-based builds

[CI/CD] Git SHA tag Container-based builds

[CI/CD] Parity Dev, staging, production

[CI/CD] Config Dev, staging, production

[CI/CD] Secrets Dev, staging, production

[CI/CD] Promotion Dev, staging, production

[CI/CD] Ephemeral Dev, staging, production

[CI/CD] workflow GitHub's CI/CD

[CI/CD] jobs/runner GitHub's CI/CD

[CI/CD] actions/checkout GitHub's CI/CD

[CI/CD] Secrets GitHub's CI/CD

[CI/CD] Matrix strategy GitHub's CI/CD

[CI/CD] Stages Automated workflow steps

[CI/CD] Triggers Automated workflow steps

[CI/CD] YAML config Automated workflow steps

[CI/CD] Artifacts Automated workflow steps

[CI/CD] CI vs CD Automated workflow steps

[CI/CD] Unit first Automated quality gates

[CI/CD] Integration Automated quality gates

[CI/CD] E2E Automated quality gates

[CI/CD] Flaky handling Automated quality gates

[CI/CD] Coverage reports Automated quality gates

[CSS] @keyframes Keyframes and transitions

[CSS] transition Keyframes and transitions

[CSS] easing Keyframes and transitions

[CSS] fill-mode Keyframes and transitions

[CSS] will-change Keyframes and transitions

[CSS] Content Content, padding, border, margin

[CSS] Padding Content, padding, border, margin

[CSS] Border Content, padding, border, margin

[CSS] Margin Content, padding, border, margin

[CSS] justify-content One-dimensional layout

[CSS] align-items One-dimensional layout

[CSS] gap One-dimensional layout

[CSS] flex-wrap One-dimensional layout

[CSS] flex-direction One-dimensional layout

[CSS] grid-template-columns Two-dimensional layout

[CSS] grid-template-areas Two-dimensional layout

[CSS] auto-fill Two-dimensional layout

[CSS] place-items Two-dimensional layout

[CSS] subgrid Two-dimensional layout

[CSS] relative Where element renders

[CSS] absolute Where element renders

[CSS] fixed Where element renders

[CSS] sticky Where element renders

[CSS] static Where element renders

[CSS] Media queries Adapt to viewport

[CSS] Container queries Adapt to viewport

[CSS] clamp() Adapt to viewport

[CSS] Viewport units Adapt to viewport

[CSS] aspect-ratio Adapt to viewport

Practice now, dominate the arena