The library

71 briefs across 9 tracks, graded case by case.

Every brief runs against a sandbox of simulated APIs and grades your webhook response case by case. 19 are free to run right now.

Run your first brief free

Foundations

RefBriefDomainCasesLevelAccess

NX-101Webhook EchoFundamentals5BeginnerFree NX-102Data TransformerFundamentals5BeginnerFree NX-137CSV Line ParserFundamentals6BeginnerFree NX-104Conditional LogicFundamentals6BeginnerFree NX-138Personalized GreetingsFundamentals6BeginnerFree NX-105Array ProcessorFundamentals5BeginnerFree NX-139Date & Time FormatterFundamentals8BeginnerFree NX-106Your First API CallFundamentals6BeginnerFree NX-103Field MapperFundamentals5BeginnerFree NX-125DeduplicationFundamentals5BeginnerFree NX-126Error EnrichmentFundamentals5IntermediateFree

API Mastery

RefBriefDomainCasesLevelAccess

NX-107Customer LookupAPIs5BeginnerLifetime NX-110Inventory CheckAPIs5BeginnerLifetime NX-111Data ValidatorAPIs5BeginnerLifetime NX-109Order EnrichmentAPIs5BeginnerLifetime NX-128Dependent CallsAPIs7BeginnerLifetime NX-108Product CatalogAPIs5IntermediateLifetime NX-112Bulk ProcessorAPIs6BeginnerLifetime NX-127Multi-Product OrderAPIs7IntermediateLifetime

Error Handling & Resilience

RefBriefDomainCasesLevelAccess

NX-113Handle Not FoundError handling5BeginnerFree NX-114Retry BasicsError handling5BeginnerFree NX-115Status PollerError handling6IntermediateFree NX-116Partial Failure HandlerError handling5IntermediateFree NX-123Timeout HandlerError handling6IntermediateFree NX-156Know When to StopError handling6IntermediateFree NX-117Rate Limit HandlerError handling5AdvancedFree

Integration Patterns

RefBriefDomainCasesLevelAccess

NX-119API Key AuthenticationIntegrations3BeginnerLifetime NX-155Verify the SignatureIntegrations6IntermediateLifetime NX-121Data AggregationIntegrations5BeginnerLifetime NX-132Appointment SchedulerScheduling7IntermediateLifetime NX-122Smart RouterIntegrations6IntermediateLifetime NX-118Idempotency GuardianIntegrations5IntermediateLifetime NX-157Cache the LookupIntegrations5IntermediateLifetime NX-120Pagination HandlerIntegrations4AdvancedLifetime NX-124Batch with LimitsIntegrations5AdvancedLifetime NX-158Contact Sync at ScaleIntegrations5AdvancedLifetime

Business Rules

RefBriefDomainCasesLevelAccess

NX-130Territory RouterSales ops11BeginnerLifetime NX-133QuickCart Order SystemE-commerce8BeginnerLifetime NX-131Lead Scoring EngineSales ops10IntermediateLifetime NX-134GrowthLabs Lead PipelineSales ops13IntermediateLifetime NX-129Subscription Renewal CheckerBilling9IntermediateLifetime NX-136HomeFind Inquiry RouterReal estate6AdvancedLifetime NX-135CloudMetrics Usage BillingBilling5AdvancedLifetime

Client Briefs

RefBriefDomainCasesLevelAccess

NX-147Northwind Goods Order PipelineE-commerce6IntermediateLifetime NX-152Northwind Goods, Part 2: RefundsPayments7IntermediateLifetime NX-150Fernwood Fitness Failed Payment RecoveryPayments6IntermediateLifetime NX-151Harbor Software Support TriageSupport7IntermediateLifetime NX-149Brightpath Coaching Lead IntakeSales ops7IntermediateLifetime NX-166Greyfern Consulting Lead CaptureSales ops10IntermediateLifetime NX-159Ashgrove Software Ticket EscalationSupport10IntermediateLifetime NX-161Larkin Partners Pipeline SyncSales ops10AdvancedLifetime NX-162Orbital Metrics Failed Payment DunningBilling10AdvancedLifetime NX-148Lumen & Co. Order AlertsE-commerce7AdvancedLifetime

Ops & Internal Tools

RefBriefDomainCasesLevelAccess

NX-160Pinecrest Studio Employee OnboardingHR ops12AdvancedLifetime NX-163Saltmarsh Media Content PublishingMarketing10IntermediateLifetime NX-165Bramble Supply Reorder AlertsInventory10IntermediateLifetime NX-164Rowan Legal Signature ArchiveDocuments10AdvancedLifetime NX-167Coppergate Labs Issue BridgeEngineering10IntermediateLifetime

Change Requests

RefBriefDomainCasesLevelAccess

NX-168Lumen & Co., Part 2: The ThreadE-commerce8IntermediateLifetime NX-169Brightpath Coaching, Part 2: The WaitlistSales ops8IntermediateLifetime NX-170Fernwood Fitness, Part 2: One Ticket Per MemberPayments8IntermediateLifetime NX-171Northwind Goods, Part 3: The Refund PolicyPayments8IntermediateLifetime NX-172Coppergate Labs, Part 2: Stop Cross-PostingEngineering8IntermediateLifetime NX-173Harbor Software, Part 2: The CRM MoveSupport8AdvancedLifetime

AI Automation

RefBriefDomainCasesLevelAccess

NX-140Text SummarizationAI / RAG5BeginnerFree NX-141Order Data ExtractionAI / RAG5BeginnerLifetime NX-142Support Ticket ClassificationAI / RAG6IntermediateLifetime NX-143Product Description GeneratorAI / RAG5BeginnerLifetime NX-144Smart Email RouterAI / RAG6IntermediateLifetime NX-145Document Q&A BotAI / RAG5IntermediateLifetime NX-146Knowledge Base AssistantAI / RAG4AdvancedLifetime