Save Version
Save a new immutable version. Never touches what’s published — see POST …/publish. Any field left unset carries over from the current latest_version_id, matching the old content-bearing PATCH’s ergonomics.
Authorizations
Enter your MeshAPI key (rsk_...) or, for the admin-keys endpoints, a dashboard session token — sent as Authorization: Bearer <token>.
Headers
Dated version of the API contract to pin this request to. Omit it and the request is served under 2026-08 — the oldest supported version, so an existing integration is never moved by a release. A malformed or unsupported value is rejected with 400 invalid_api_version rather than falling back silently. The version actually served is echoed as X-Mesh-Version on every response, including errors.
2026-08, 2026-09 Path Parameters
Body
A new immutable snapshot of a template's behavioral content. A field
left unset carries over from latest_version_id — changing just system
doesn't require resending messages.
Response
Successful Response