API Versioning Best Practices

Why Version APIs?

Versioning lets you improve your API without breaking existing clients. When you make breaking changes, a new version protects old integrations.

Versioning Strategies

Method	Example
URL path	/api/v1/users
Query param	/users?version=1
Header	Accept: application/vnd.api.v1+json

URL Versioning (Most Common)

/api/v1/users   # original
/api/v2/users   # new version with changes

Simple, visible, and easy to test — the most popular choice.

What Counts as a Breaking Change?

• Removing/renaming fields.
• Changing data types.
• Changing response structure.

Non-Breaking (No New Version Needed)

• Adding new optional fields.
• Adding new endpoints.

Best Practices

• Version from day one (/v1).
• Support old versions during migration.
• Communicate deprecation timelines.

FAQs

Which strategy is best?

URL versioning (/v1) — clearest and easiest. More in our API Development guides.

How long to keep old versions?

Give clients ample notice — often 6-12 months before retiring.