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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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153 challenges matching your filters
Clear topic filter- Multiple ChoiceIntermediate
Fitness functions
architectureevolutionary-architecturefitness-functions - Multiple ChoiceBeginner
ADRs purpose
architectureadrdocumentation - Multiple ChoiceIntermediate
Feature flags vs branches
architecturefeature-flagscicd - Multiple ChoiceHard
Feature flag debt
architecturefeature-flagstechnical-debt - Multiple ChoiceBeginner
Cyclic dependencies harm
architecturemodularitydependencies - Multiple ChoiceIntermediate
Stable Dependencies Principle
architecturemetricssdp - Multiple ChoiceBeginner
Package cohesion: CCP
architecturemodularitycohesion - Multiple ChoiceHard
Boundary leak via shared database
architecturemicroservicescoupling - Multiple ChoiceIntermediate
Idempotency key design
architectureresilienceidempotency - Multiple ChoiceBeginner
Facade reduces coupling
architecturedesign-patternsfacade - Multiple ChoiceIntermediate
Decorator ordering matters
architecturedesign-patternsdecorator - Multiple ChoiceIntermediate
Strategy vs State
architecturedesign-patternsstrategystate - Multiple ChoiceIntermediate
Bulkhead pattern
architectureresiliencebulkhead - Multiple ChoiceHard
Thundering herd on cache expiry
architectureresiliencecaching - Multiple ChoiceHard
Backpressure vs dropping
architectureresiliencebackpressure - Multiple ChoiceHard
Consistency boundary choice
architecturedddconsistency - Multiple ChoiceBeginner
Cross-cutting logging
architecturecross-cuttinglogging - Multiple ChoiceHard
Correlation ids in distributed tracing
architectureobservabilitytracing - Multiple ChoiceBeginner
Config as external concern
architectureconfigurationtwelve-factor - Multiple ChoiceBeginner
Composition over inheritance
architectureoopcomposition - Multiple ChoiceHard
Fragile base class problem
architectureoopinheritance - Multiple ChoiceHard
Aggregate size trade-off
architecturedddaggregate - Multiple ChoiceIntermediate
Event-carried state transfer vs notification
architectureedacoupling - Multiple ChoiceIntermediate
Interface versioning in events
architectureedaversioning - Multiple ChoiceHard
Modularity enforcement
architecturemodularityfitness-functions - Multiple ChoiceBeginner
Anti-corruption in practice
architecturedddacl - Multiple ChoiceHard
Domain service vs application service
architecturedddlayering - Multiple ChoiceHard
Rich model invariant
architecturedddinvariants - Multiple ChoiceIntermediate
Make illegal states unrepresentable
architecturedddtype-modeling - Multiple ChoiceBeginner
Port naming by role
architecturehexagonalnaming - Multiple ChoiceHard
Strangler routing: shadow traffic
architecturemigrationstrangler-fig - Multiple ChoiceHard
Service granularity trap
architecturemicroservicesgranularity - Multiple ChoiceIntermediate
Architecture vs design decision
architecturedecision-making - Code AnalysisBeginner
Anemic model allows invalid state
architecturedddanemic-model - Code AnalysisIntermediate
Violated LSP with strengthened precondition
architecturesolidlsp - Code AnalysisIntermediate
Circular dependency between modules
architecturemodularitydependencies - Code AnalysisIntermediate
Wrong abstraction: premature interface
architectureover-abstractiondi - Code AnalysisIntermediate
Coupling leak: vendor type in domain
architecturesoliddiphexagonal - Code AnalysisIntermediate
Observer memory leak
architecturedesign-patternsobserver - Code AnalysisBeginner
SRP: god class
architecturesolidsrp - Code AnalysisIntermediate
Unit of Work spanning aggregates
architecturedddunit-of-work - Code AnalysisIntermediate
Strategy gone wrong: enum switch
architecturesolidocp - Code AnalysisIntermediate
Eventual consistency bug after write
architecturecqrseventual-consistency - Code AnalysisIntermediate
Decorator vs subclass explosion
architecturedesign-patternsdecorator - Code AnalysisHard
Saga: non-idempotent compensation
architecturedistributedsagaidempotency - Code AnalysisIntermediate
Circuit breaker covers wrong scope
architectureresiliencecircuit-breaker - Code AnalysisHard
Dual-write inconsistency
architectureedaoutbox - Code AnalysisBeginner
LSP: equals/hashCode mismatch
architecturesolidlsp - Code AnalysisBeginner
Coupling metric read
architecturemetricscoupling - Code AnalysisIntermediate
Fitness function for layering
architecturefitness-functionshexagonal - Code AnalysisIntermediate
Repository leaking persistence
architecturedesign-patternsrepository - Code AnalysisIntermediate
Aggregate reference by object
architecturedddaggregate - Code AnalysisIntermediate
Strangler with broken routing
architecturemigrationstrangler-fig - Code AnalysisHard
Facade hides subsystem steps
architecturedesign-patternsfacade - Code AnalysisIntermediate
Wrong abstraction via forced hierarchy
architectureover-abstractionlsp - Code AnalysisBeginner
Command with undo
architecturedesign-patternscommand - Code AnalysisIntermediate
Ambassador vs Sidecar use
architecturedesign-patternssidecarambassador - Code AnalysisIntermediate
Adapter vs Facade distinction by code
architecturedesign-patternsadapter - Code AnalysisIntermediate
Bounded context language clash
architecturedddbounded-context - Code AnalysisBeginner
Feature flag stale branch
architecturefeature-flagstechnical-debt
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