Also struggling with this. Any updates from @colinfromkitchener or @vlprof ?

There documentation is poor to put it mildly. After much trial and error here's what I determined is needed for the POST body: { "data": { "type": "appStoreVersionReleaseRequests", "relationships": { "appStoreVersion": { "data": { "id": "${the_id_of_the_version_to_release}", "type": "appStoreVersions" } } } } } Your curl command would look like this: curl -v -g -X 'POST' -H 'Authorization: Bearer ${JWT}' -H 'Content-Type: application/json' 'https://api.appstoreconnect.apple.com/v1/appStoreVersionReleaseRequests' --data '{"data":{"type":"appStoreVersionReleaseRequests","relationships":{"appStoreVersion":{"data":{"id": "${the_id_of_the_version_to_release}","type": "appStoreVersions"}}}}}'