API Design Lab

Design rate limiting headers and 429 responses that don't leave developers guessing.

Design HTTP caching with ETags, If-None-Match, and Cache-Control headers.

Design batch endpoints with partial success handling and 207 Multi-Status.

Design a webhook system with event types, HMAC signing, and retry policies.

Implement idempotency keys for safe retries on payment and order creation.

Design async operation patterns with 202 Accepted and polling endpoints.

Design file upload/download APIs with presigned URLs and resumable uploads.

Design an advanced search API with facets, highlighting, and suggestions.

Design your first GraphQL schema - types, fields, queries, and non-null markers.

Design GraphQL mutations with input types and proper return types.

Solve the N+1 problem with DataLoader batching and resolver chain design.

Implement Relay-style cursor pagination with edges, nodes, and pageInfo.

Design GraphQL subscriptions for real-time updates over WebSocket.

Design field-level authorization with @auth directives and type policies.

Protect your GraphQL API from malicious queries using depth limiting and complexity analysis.

Design a federated GraphQL schema with Apollo Federation directives.

Design custom scalar types for type-safe validation - DateTime, Email, URL, JSON.

Evolve a GraphQL schema without breaking existing clients - deprecation, aliases, and additive changes.

Design your first Protocol Buffer schema - messages, services, and field numbers.

Design a multi-service gRPC architecture with well-defined contracts.

Design gRPC streaming RPCs - server streaming, client streaming, and bidirectional.

Evolve a proto schema safely - backward and forward compatibility rules.

Design gRPC error handling with status codes, error details, and rich error models.

Design deadline propagation across a chain of gRPC services.

Design domain events for an e-commerce system - event naming, payload design, and event catalog.

Design a saga pattern for distributed transactions with compensating actions.

Design a CQRS architecture separating commands from queries with event sourcing.

Design a schema registry for event contracts with versioning and compatibility checking.

Design exactly-once processing with idempotent consumers and outbox pattern.

Design dead letter queues, retry policies, and poison message handling.

Design an API Gateway with routing, auth, rate limiting, and protocol translation.

Design Backend-for-Frontend APIs optimized for web, mobile, and TV clients.

Design a multi-tier rate limiting system with token bucket, sliding window, and quota management.

Design a developer portal with API key management, OAuth flows, and usage analytics.

Design APIs with circuit breaker patterns, fallbacks, and bulkhead isolation.

Design a service mesh with sidecar proxies, mTLS, observability, and traffic management.

Full system design: Payment processing API like Stripe with idempotency, webhooks, and PCI compliance.

Full system design: Real-time chat API with WebSocket, presence, read receipts, and message history.

Full system design: Food delivery platform with location tracking, real-time ETAs, and multi-party coordination.

The ultimate challenge: design a complete multi-protocol API platform combining REST, GraphQL, gRPC, and events.