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
4,318 challenges matching your filters
- 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 - Multiple ChoiceIntermediate
[CSS] ID Which rule wins
qacsscssqa - Multiple ChoiceIntermediate
[CSS] Class Which rule wins
qacsscssqa - Multiple ChoiceIntermediate
[CSS] Element Which rule wins
qacsscssqa - Multiple ChoiceIntermediate
[CSS] !important Which rule wins
qacsscssqa - Multiple ChoiceIntermediate
[CSS] Inline style Which rule wins
qacsscssqa - Multiple ChoiceBeginner
[CSS] Declare --name: value
qacsscssqa - Multiple ChoiceBeginner
[CSS] Use --name: value
qacsscssqa - Multiple ChoiceBeginner
[CSS] Fallback --name: value
qacsscssqa - Multiple ChoiceBeginner
[CSS] Inheritance --name: value
qacsscssqa - Multiple ChoiceBeginner
[CSS] JavaScript --name: value
qacsscssqa - Multiple ChoiceIntermediate
[Docker] YAML Multi-container with docker-compose.yml
qadockerdockerqa - Multiple ChoiceIntermediate
[Docker] Network Multi-container with docker-compose.yml
qadockerdockerqa - Multiple ChoiceIntermediate
[Docker] Volumes Multi-container with docker-compose.yml
qadockerdockerqa - Multiple ChoiceIntermediate
[Docker] depends_on Multi-container with docker-compose.yml
qadockerdockerqa - Multiple ChoiceIntermediate
[Docker] Profiles Multi-container with docker-compose.yml
qadockerdockerqa - Multiple ChoiceBeginner
[Docker] FROM Image build instructions
qadockerdockerqa - Multiple ChoiceBeginner
[Docker] RUN Image build instructions
qadockerdockerqa - Multiple ChoiceBeginner
[Docker] CMD vs ENTRYPOINT Image build instructions
qadockerdockerqa - Multiple ChoiceBeginner
[Docker] COPY vs ADD Image build instructions
qadockerdockerqa - Multiple ChoiceBeginner
[Docker] ENV Image build instructions
qadockerdockerqa - Multiple ChoiceIntermediate
[Docker] Dockerfile Container readiness probe
qadockerdockerqa - Multiple ChoiceIntermediate
[Docker] Interval Container readiness probe
qadockerdockerqa - Multiple ChoiceIntermediate
[Docker] Retries Container readiness probe
qadockerdockerqa - Multiple ChoiceIntermediate
[Docker] depends_on condition Container readiness probe
qadockerdockerqa - Multiple ChoiceIntermediate
[Docker] Exit codes Container readiness probe
qadockerdockerqa - Multiple ChoiceIntermediate
[Docker] Copy-on-write Image filesystem layers
qadockerdockerqa - Multiple ChoiceIntermediate
[Docker] Cache Image filesystem layers
qadockerdockerqa - Multiple ChoiceIntermediate
[Docker] Order Image filesystem layers
qadockerdockerqa - Multiple ChoiceIntermediate
[Docker] Squash Image filesystem layers
qadockerdockerqa - Multiple ChoiceIntermediate
[Docker] Multi-stage Image filesystem layers
qadockerdockerqa - Multiple ChoiceHard
[Docker] FROM ... AS Separate build and runtime
qadockerdockerqa - Multiple ChoiceHard
[Docker] COPY --from Separate build and runtime
qadockerdockerqa - Multiple ChoiceHard
[Docker] FROM scratch Separate build and runtime
qadockerdockerqa - Multiple ChoiceHard
[Docker] Benefits Separate build and runtime
qadockerdockerqa - Multiple ChoiceHard
[Docker] Go compilation Separate build and runtime
qadockerdockerqa - Multiple ChoiceHard
[Docker] Bridge Container connectivity
qadockerdockerqa - Multiple ChoiceHard
[Docker] Host Container connectivity
qadockerdockerqa - Multiple ChoiceHard
[Docker] Overlay Container connectivity
qadockerdockerqa
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.