ButterCMS vs Prismic

ButterCMS

The Read and Write APIs have a public OpenAPI 3.1 file, Markdown docs and a status page with no incident since October 2025. The Write API is a paid add-on from the $249 plan, capped at 2,000 or 5,000 calls a month. Writes answer 202 with no identifier, support rotates tokens, and the terms are an undated website document.

Prismic

The hosted MCP server stages every write as a draft in a release, cannot delete, and publishes only when a user with the Publisher role asks. Write tokens for the Migration, Asset and Types APIs have no scopes, no OpenAPI file was found, writes are limited to one request a second, and the acceptable use policy forbids access by scripts.

ButterCMS

1. End every path with a slash. A missing slash returns a 301, and the vendor counts the redirect and the retry as two API calls
2. Send the write token only as Authorization: Token <token>. The auth_token query parameter works for reads only
3. On page creation send every field key of the page type, with empty strings for fields left blank
4. A 202 means queued, not saved. Read the entry back with preview=1 to confirm, and check a slug exists before retrying a create
5. Call the REST API directly for writes. The JavaScript SDK 3.0.3 has list, retrieve and search methods only

Prismic

1. Ask a repository Administrator to activate Prismic MCP in Settings first. Activation can take several minutes, and each environment has its own setting
2. Call list_repositories, then get_custom_type or get_shared_slice for the empty content template before create_document
3. Create a release with create_release and write into it. Call publish_release only on an explicit request, because a publish cannot be undone through MCP
4. For the Migration API send Authorization: Bearer <write token> and a repository header, one page a request, one request a second, and keep each returned id for later PUT calls
5. Upload media first (upload_asset or POST to https://asset-api.prismic.io/assets) and reference the asset id in image and media link fields