Overview

Accept-Post is a response header by which the server states which media type(s) a particular resource accepts in a POST request body. It lets clients learn in advance what they may POST.

The value is a list of MIME types the server accepts (e.g. `Accept-Post: application/json, text/plain, image/webp`).

Details

Where the request-side Accept expresses 'what I want to receive in the response,' Accept-Post is the reverse-direction negotiation info telling clients 'what this endpoint accepts via POST.' It typically rides on an OPTIONS response or resource-metadata response, guiding clients to POST with the correct Content-Type.

It is conceptually identical to Accept-Patch, the PATCH counterpart (which advertises the types PATCH accepts). Used with the Allow header (which lists supported methods), a client can learn in one shot that a resource supports POST and which formats it accepts.

When a POST arrives with an unsupported type, servers commonly reject it with 415 Unsupported Media Type; Accept-Post acts as a hint to prevent that failure up front. An empty value can be read as 'accepts no type,' so be careful.

Syntax

Accept-Post: <media-type>[, <media-type>]*

e.g. Accept-Post: application/json, text/plain, image/webp

Notes

• Accept (request, desired response type) and Accept-Post (response, types the server accepts via POST) point in opposite directions — don't confuse them.
• POSTing an unsupported type returns 415 Unsupported Media Type; Accept-Post is the hint that prevents this failure.
• Accept-Patch is the PATCH counterpart and Allow lists supported methods; exposing them together eases client integration.

Related headers

Specification