API Versioning & Compatibility

Strategies for managing API versions, backward compatibility, and graceful deprecation.

Versioning Approaches

URL Path Versioning

/api/v1/users
/api/v2/users

Query Parameter Versioning

GET /api/users?version=1
GET /api/users?version=2

Header Versioning

Accept: application/vnd.api+json;version=1

Content Negotiation

Accept: application/vnd.myapi.v2+json

Best Practices

1. Semantic Versioning - Use MAJOR.MINOR.PATCH
2. Deprecation Warnings - Include deprecation headers
3. Sunset Headers - Specify when API versions expire
4. Changelog - Document all changes
5. Migration Guides - Help clients upgrade
6. Compatibility Layer - Support multiple versions temporarily

Breaking Changes Strategy

• Plan deprecation timeline (6-12 months notice)
• Provide migration documentation
• Offer tool-assisted migration (scripts, adapters)
• Support parallel versioning
• Communicate clearly in changelogs

References

• Semantic Versioning (semver.org)
• REST API Design Guidelines
• OpenAPI/Swagger Specification