API Contracts
& Client Workflows
The authoritative reference for designing robust API endpoints, generating type-safe clients, and evolving contracts safely — from schema composition and error contracts to breaking-change detection and SDK release pipelines.
Contract-First. Production-Ready.
Deep-dive guidance for backend engineers, API architects, and platform teams who build and consume APIs at scale. Every pattern here is grounded in real-world production concerns: versioning, type safety, retry semantics, and automated SDK generation.
From Design to Client
We cover the full API lifecycle: modeling resources with clean HTTP semantics, composing OpenAPI schemas that generate readable client types, publishing SDKs from CI, detecting breaking changes before release, and mapping every failure mode to a machine-readable error contract.
Patterns Across Languages
Examples span TypeScript, Node.js, Go, Python, and YAML-based OpenAPI specs. Whether you're building REST endpoints, configuring retry policies, or implementing cursor-based pagination with PostgreSQL, you'll find production-grade patterns here.
Explore the Guides
Four focused sections — now 22 in-depth topic guides and 60 practical walkthroughs covering the full contract lifecycle.
API Design Fundamentals & Architecture
Resource modeling, HTTP method semantics, idempotency key patterns, schema composition with allOf and oneOf, and the pipelines that turn a contract into published SDKs.
- Resource Modeling Best Practices
- HTTP Method Mapping Guidelines
- Idempotency Key Implementation
- Statelessness & Caching Strategies
- OpenAPI Schema Composition
- Client SDK Generation Pipelines
Error Contracts & Resilience Mapping
RFC 7807 Problem+JSON, status code classification, retryable vs non-retryable errors, rate limit and quota contracts, field-level validation payloads, and circuit breakers.
- RFC 7807 Problem+JSON Implementation
- HTTP Status Code Mapping
- Retryable vs Non-Retryable Errors
- Client Fallback Strategies
- Rate Limiting & Quota Contracts
- Validation Error Payloads
Query Patterns & Data Shaping Strategies
Cursor vs offset pagination, advanced boolean filtering, multi-field sorting, sparse fieldsets, and response envelopes that can carry metadata without breaking clients.
- Offset vs Cursor Pagination
- Advanced Filtering Operators
- Sorting & Multi-field Ordering
- Sparse Fieldsets & Projection
- Response Envelopes & Metadata
API Versioning & Deprecation
URL-path vs header versioning, Sunset and Deprecation headers, breaking change detection with spec diffs, changelog automation, and SDK pinning with semver ranges.
- URL Path vs Header Versioning
- Sunset & Deprecation Headers
- API Changelog Automation
- SDK Version Pinning
- Breaking Change Detection