Designing APIs That Survive Product Evolution
Table of Contents
- The Cost of Breaking Changes
- Versioning Strategies (Header vs. URL)
- The Power of the Expansion Pattern
- Automated Contract Testing
- GraphQL vs. REST for Evolution
- FAQ
Introduction
An API is a forever commitment. Once third-party developers build on your platform, every breaking change costs you trust and engineering time. Building an "Evolvable" API means planning for features you haven't even thought of yet.
Core Concepts: The Expansion Pattern
Instead of removing fields, always Add and Deprecate.
- Never rename a field.
- Create a new field, support both for 12 months, and log warnings for the old one.
Architecture Breakdown: Contract Testing
Use tools like Pact or Optic to ensure that your API implementation always matches your documentation (OpenAPI/Swagger).