API Versioning Strategy

Breaking changes kill APIs. One bad deploy and your mobile app crashes, your partners file tickets, and your Slack lights up at 2 AM. This skill gives you the versioning strategy that prevents all of it.

What you get:

• Three versioning approaches compared (URL path, header, content negotiation) with clear decision criteria
• Migration playbooks for moving consumers between versions without downtime
• Deprecation lifecycle management: sunset headers, grace periods, and communication templates
• Version negotiation middleware patterns for Express, Fastify, and NestJS
• OpenAPI/Swagger multi-version documentation setup
• Database schema versioning that supports multiple API versions simultaneously
• Feature flag integration for gradual version rollouts
• Real-world examples: how Stripe, GitHub, and Twilio version their APIs

Works with REST, GraphQL, and gRPC. Framework-agnostic patterns you can apply to any stack.

If you have paying API consumers or external integrations, this skill pays for itself the first time it prevents a breaking change from reaching production.