# 4626.fun API versioning

The 4626.fun Agent API is versioned in the URL as `/api/v1/`. A future major version would be `/api/v2/` and would not silently replace v1.

Deprecated operations send:

- `Deprecation: true` (RFC 9745)
- `Sunset` HTTP-date (RFC 8594)
- `Link: </developers/versioning>; rel="deprecation"`

OpenAPI marks those operations `deprecated: true`. Additive JSON fields are not breaking. Removals need a new version or a documented sunset. Retired example: POST `/api/v1/lottery/amoe/xmtp-checkin` returns 410.