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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Clear topic filter- Multiple ChoiceHard
[HTTP API] Upgrade Full-duplex TCP tunnel over HTTP
qahttphttpqa - Multiple ChoiceHard
[HTTP API] Secure Full-duplex TCP tunnel over HTTP
qahttphttpqa - Multiple ChoiceHard
[HTTP API] Ping/Pong Full-duplex TCP tunnel over HTTP
qahttphttpqa - Multiple ChoiceHard
[HTTP API] Close frame Full-duplex TCP tunnel over HTTP
qahttphttpqa - Multiple ChoiceHard
[HTTP API] Subprotocol Full-duplex TCP tunnel over HTTP
qahttphttpqa - Multiple ChoiceHard
[JavaScript] yield Pausable functions with yield
qajavascriptjavascriptqa - Multiple ChoiceHard
[JavaScript] next() Pausable functions with yield
qajavascriptjavascriptqa - Multiple ChoiceHard
[JavaScript] Iterator Pausable functions with yield
qajavascriptjavascriptqa - Multiple ChoiceHard
[JavaScript] yield* Pausable functions with yield
qajavascriptjavascriptqa - Multiple ChoiceHard
[JavaScript] Async gen Pausable functions with yield
qajavascriptjavascriptqa - Multiple ChoiceHard
[JavaScript] Get trap Intercept object operations
qajavascriptjavascriptqa - Multiple ChoiceHard
[JavaScript] Set trap Intercept object operations
qajavascriptjavascriptqa - Multiple ChoiceHard
[JavaScript] Revocable Intercept object operations
qajavascriptjavascriptqa - Multiple ChoiceHard
[JavaScript] Reflect Intercept object operations
qajavascriptjavascriptqa - Multiple ChoiceHard
[JavaScript] Delete Intercept object operations
qajavascriptjavascriptqa - Multiple ChoiceHard
[JavaScript] GC Memory-safe keyed collections
qajavascriptjavascriptqa - Multiple ChoiceHard
[JavaScript] Use case Memory-safe keyed collections
qajavascriptjavascriptqa - Multiple ChoiceHard
[JavaScript] No iteration Memory-safe keyed collections
qajavascriptjavascriptqa - Multiple ChoiceHard
[JavaScript] Object keys only Memory-safe keyed collections
qajavascriptjavascriptqa - Multiple ChoiceHard
[JavaScript] vs Map Memory-safe keyed collections
qajavascriptjavascriptqa - Multiple ChoiceHard
[Kubernetes] Metrics Horizontal Pod Autoscaler
qak8sk8sqa - Multiple ChoiceHard
[Kubernetes] Custom metrics Horizontal Pod Autoscaler
qak8sk8sqa - Multiple ChoiceHard
[Kubernetes] Min/max replicas Horizontal Pod Autoscaler
qak8sk8sqa - Multiple ChoiceHard
[Kubernetes] Stabilization window Horizontal Pod Autoscaler
qak8sk8sqa - Multiple ChoiceHard
[Kubernetes] VPA Horizontal Pod Autoscaler
qak8sk8sqa - Multiple ChoiceHard
[Kubernetes] Host rules HTTP routing to services
qak8sk8sqa - Multiple ChoiceHard
[Kubernetes] Path rules HTTP routing to services
qak8sk8sqa - Multiple ChoiceHard
[Kubernetes] TLS termination HTTP routing to services
qak8sk8sqa - Multiple ChoiceHard
[Kubernetes] Annotations HTTP routing to services
qak8sk8sqa - Multiple ChoiceHard
[Kubernetes] Gateway API HTTP routing to services
qak8sk8sqa - Multiple ChoiceHard
[Kubernetes] Role Role-Based Access Control
qak8sk8sqa - Multiple ChoiceHard
[Kubernetes] ClusterRole Role-Based Access Control
qak8sk8sqa - Multiple ChoiceHard
[Kubernetes] RoleBinding Role-Based Access Control
qak8sk8sqa - Multiple ChoiceHard
[Kubernetes] Least privilege Role-Based Access Control
qak8sk8sqa - Multiple ChoiceHard
[Kubernetes] Aggregation Role-Based Access Control
qak8sk8sqa - Multiple ChoiceHard
[Linux] CPU Resource limits for processes
qalinuxlinuxqa - Multiple ChoiceHard
[Linux] Memory Resource limits for processes
qalinuxlinuxqa - Multiple ChoiceHard
[Linux] IO Resource limits for processes
qalinuxlinuxqa - Multiple ChoiceHard
[Linux] PIDs Resource limits for processes
qalinuxlinuxqa - Multiple ChoiceHard
[Linux] Hierarchy Resource limits for processes
qalinuxlinuxqa - Multiple ChoiceHard
[Linux] ip addr Network stack tools
qalinuxlinuxqa - Multiple ChoiceHard
[Linux] ss Network stack tools
qalinuxlinuxqa - Multiple ChoiceHard
[Linux] iptables/nftables Network stack tools
qalinuxlinuxqa - Multiple ChoiceHard
[Linux] tcpdump Network stack tools
qalinuxlinuxqa - Multiple ChoiceHard
[Linux] SO_REUSEPORT Network stack tools
qalinuxlinuxqa - Multiple ChoiceHard
[Linux] Units Init system and service manager
qalinuxlinuxqa - Multiple ChoiceHard
[Linux] journalctl Init system and service manager
qalinuxlinuxqa - Multiple ChoiceHard
[Linux] Wants vs Requires Init system and service manager
qalinuxlinuxqa - Multiple ChoiceHard
[Linux] Type=forking Init system and service manager
qalinuxlinuxqa - Multiple ChoiceHard
[Linux] Restart policy Init system and service manager
qalinuxlinuxqa - Multiple ChoiceHard
[MongoDB] $match Multi-stage data processing
qamongodbmongodbqa - Multiple ChoiceHard
[MongoDB] $group Multi-stage data processing
qamongodbmongodbqa - Multiple ChoiceHard
[MongoDB] $lookup Multi-stage data processing
qamongodbmongodbqa - Multiple ChoiceHard
[MongoDB] $unwind Multi-stage data processing
qamongodbmongodbqa - Multiple ChoiceHard
[MongoDB] $facet Multi-stage data processing
qamongodbmongodbqa - Multiple ChoiceHard
[MongoDB] Compound Query performance
qamongodbmongodbqa - Multiple ChoiceHard
[MongoDB] Text Query performance
qamongodbmongodbqa - Multiple ChoiceHard
[MongoDB] TTL Query performance
qamongodbmongodbqa - Multiple ChoiceHard
[MongoDB] Sparse Query performance
qamongodbmongodbqa - Multiple ChoiceHard
[MongoDB] Wildcard Query performance
qamongodbmongodbqa
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.