● Reference

Versioning

The API versions by date, pinned per key. Send Anvil-Version: 2026-07-05 on every request; omit it and your key pins to the version current at first call.

Stable + additive

The surface is stable and grows additively: new operations, fields, and events ship anytime with a changelog entry. Breaking changes (renames, removals, shape changes) ship only under a new date version with a migration note.

How the pieces fit

The /v1 path prefix does not change. The date version (Anvil-Version) gates payload shapes: keys pin to a date at first call and stay pinned until you move them.

Machine-readable spec

The full surface ships as a validated OpenAPI 3.1 document: openapi.yaml (45 operations, 21 webhooks, 22 scopes).