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.
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2,019 challenges matching your filters
- Multiple ChoiceIntermediate
Saga vs process manager role
sagaprocess-managerevent-driven - Multiple ChoiceIntermediate
Repository vs Unit of Work roles
repositoryunit-of-work - Multiple ChoiceIntermediate
GRASP: Information Expert guidance
graspsrp - Multiple ChoiceIntermediate
Strategy vs Template Method
strategytemplate-methodcomposition - Multiple ChoiceIntermediate
Bridge pattern: separating dimensions
bridgepatterns - Multiple ChoiceIntermediate
Prototype pattern: cloning intent
prototypepatterns - Multiple ChoiceIntermediate
Mediator: reducing many-to-many coupling
mediatorcoupling - Multiple ChoiceIntermediate
Cyclic web: shotgun surgery cause
cyclic-dependenciesshotgun-surgeryanti-pattern - Multiple ChoiceIntermediate
Feature flags vs branches trade-off
feature-flagstrunk-basedci - Multiple ChoiceIntermediate
Fitness functions in evolutionary architecture
fitness-functionsevolutionary-architecture - Multiple ChoiceIntermediate
Branch by abstraction vs feature branch
branch-by-abstractionstrangler-fig - Multiple ChoiceIntermediate
Blue-green vs canary deployment
blue-greencanarydeployment - Multiple ChoiceIntermediate
Test trophy vs test pyramid
test-pyramidtest-trophytesting - Multiple ChoiceIntermediate
Architecture Quantum
architecture-quantumdeploymentcohesion - Multiple ChoiceIntermediate
HATEOAS Core Idea
hateoasresthypermedia - Multiple ChoiceIntermediate
Expand-Contract Migration Pattern
expand-contractdatabasemigration - Multiple ChoiceIntermediate
ADR Lifecycle
adrdecision-recordsgovernance - Multiple ChoiceIntermediate
Modular Monolith Boundaries
modular-monolithboundariesencapsulation - Multiple ChoiceIntermediate
API Gateway vs Service Mesh
api-gatewayservice-meshtraffic - Multiple ChoiceIntermediate
Sidecar vs Library
sidecarservice-meshcross-cutting - Multiple ChoiceIntermediate
Team Topologies: Cognitive Load
team-topologiescognitive-loadorg-design - Multiple ChoiceIntermediate
Event Sourcing Snapshotting
event-sourcingsnapshottingperformance - Multiple ChoiceIntermediate
Sync engine design: checkpointing
sync-enginecheckpointingdeltas - Multiple ChoiceIntermediate
Sync vs async architecture
sync-asyncevent-drivenbusiness-flow - Multiple ChoiceIntermediate
Wrong abstraction (Sandi Metz)
wrong-abstractionsandi-metzrefactoring - Multiple ChoiceIntermediate
Anti-corruption layer at integration
anti-corruption-layerintegrationddd - Multiple ChoiceIntermediate
Incremental vs Big Design Upfront
incrementalbdufevolutionary-architecture - Multiple ChoiceIntermediate
Architect Role vs Hands-On
architect-rolehands-onenablement - Multiple ChoiceIntermediate
Architecture Enablement
enablementarchitect-roleempowerment - Multiple ChoiceIntermediate
Diagrams-as-Code Benefit
diagrams-as-codestructurizrdocumentation - Multiple ChoiceIntermediate
Quality Attributes in Diagrams
quality-attributesdiagramsviews - Multiple ChoiceIntermediate
STRIDE Threat Modeling
stridethreat-modelingsecurity - Multiple ChoiceIntermediate
Shuffle Sharding Benefit
shuffle-shardingblast-radiustenancy - Multiple ChoiceIntermediate
Strangler Fig Approach
strangler-figmigrationincremental - 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
Virtual nodes in consistent hashing
system-designconsistent-hashing - Multiple ChoiceIntermediate
TTL jitter
system-designcaching - Multiple ChoiceIntermediate
CDN invalidation tradeoff
system-designcdncache-invalidation - Multiple ChoiceIntermediate
Read-your-writes consistency
system-designconsistencyreplication - Multiple ChoiceIntermediate
PACELC extension
system-designpacelccap-theorem - Multiple ChoiceIntermediate
Serializable vs linearizable
system-designconsistency - Multiple ChoiceIntermediate
Exactly-once reality
system-designmessagingkafka - Multiple ChoiceIntermediate
Idempotency key design
system-designapi-designidempotency - Multiple ChoiceIntermediate
Backpressure
system-designmessagingbackpressure - Multiple ChoiceIntermediate
Distributed rate limiting accuracy
system-designrate-limitingdistributed - Multiple ChoiceIntermediate
Sliding window vs fixed window
system-designrate-limiting - Multiple ChoiceIntermediate
gRPC vs REST
system-designapi-designgrpc - Multiple ChoiceIntermediate
Saga pattern compensation
system-designdistributed-transactionssaga - Multiple ChoiceIntermediate
Outbox pattern
system-designdistributed-transactionsoutbox - Multiple ChoiceIntermediate
Availability math
system-designavailability - Multiple ChoiceIntermediate
Circuit breaker states
system-designavailabilitycircuit-breaker - Multiple ChoiceIntermediate
Pre-signed URLs
system-designstorages3 - Multiple ChoiceIntermediate
WebSocket vs long polling
system-designreal-timewebsockets - Multiple ChoiceIntermediate
Elasticsearch refresh vs commit
system-designsearchelasticsearch - Multiple ChoiceIntermediate
Clock skew and Snowflake
system-designunique-idsnowflake - Multiple ChoiceIntermediate
Microservices vs monolith
system-designmicroservices
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