Having multipart at the first position of enabled formats in api_platform.yaml negatively affects the api (swagger) documentation. For some reason, all requests will be generated with 'accept: multipart/form-data', which is wrong for most endpoints. See the following GET request which is generated with the "accept: multipart/form-data" header (see the curl command below):

image

This leads to responses with the error message "Serialization for the format "multipart" is not supported.".

Switching the formats in api_platform.yaml to have jsonld at the first position solves this issue:

formats:
 jsonld: ['application/ld+json']
 multipart: ['multipart/form-data']

Now, the request is generated and done properly with the correct accept header:
image

I was also able to reproduce this in version 4.0. This fix does not seem to have any other side effects on both versions 4.0 and 4.1. Can somebody confirm this?

Greetings!