# API changelog

Dated changes to the Layer REST API, newest first. This changelog covers API-surface changes (new versions, new endpoints, breaking changes, deprecations). For SDK and MCP changes, see their own release notes.

## 2026-08-26 — v2 is now the default

**v2 of the Layer REST API is live and is the default across these docs.** Every endpoint is available under `/v2`; v1 remains live under `/v1` and will be deprecated as a whole later.

* **Changed:** inference endpoints move from `model_id` \+ `weight` to `base_model_id` \+ `modality` \+ optional `reference_sets`, and inference responses gain base-model/reference-set fields. Models endpoints are renamed to Base Models. See the [v1 → v2 migration guide](/docs/migration) for the full list.
* **New:** `…/base-models/{slug}/inference-schema`, `…/base-models/{slug}/inferences`, and `…/reference-sets` endpoints.
* **Unchanged:** all other endpoints are drop-in — identical schemas in v1 and v2.

The docs now carry the version in the URL (`/docs/v2/…`, `/docs/v1/…`), and v1 pages point at their v2 equivalents.

Note

Earlier API changes predate this changelog. The full v1 surface remains documented under </docs/v1/rest-api> while v1 is live.