Answers how much has arrived.
HEAD
The answer must not be cached
It carries Cache-Control: no-store. A client that caches it anyway will
corrupt the upload: a stale offset sends the next chunk to the wrong place.
This is the one header on this endpoint that is not politeness.
Errors
404 when there is no such session, or the caller may not continue it. The
same answer, so a stranger cannot tell one from the other.
cookie
tessera_session<token>Set by POST /auth/login. A browser sends it automatically; it is HttpOnly, so page scripts cannot read or set it.
id*stringThe session
Upload-Offset says how much has arrived
curl -X HEAD 'https://example.com/api/v1/uploads/string'Empty