Versioning

APIs change

Fields get renamed, auth improves, and business rules shift. Versioning makes breaking changes explicit.

URL versioning

A clear beginner approach: put the version in the path.

GET /api/v1/books
GET /api/v2/books

Compatible changes

• Add optional fields
• Add new endpoints
• Widen accepted input carefully
• Avoid removing or renaming fields without a new version

Deprecation

Announce timelines, keep old versions for a while, and monitor usage before shutdown.