HTTP headers
Expect HTTP Header Meaning
Expect asks the server to confirm before the client sends the body.
Meaning
The client wants an interim response, most commonly 100 Continue, before uploading content.
Where it appears
Large uploads may use it to avoid sending a body the server will reject.
What to check
Check proxy support for 100 Continue and whether upload stalls happen before the request body is sent.
Example
Expect: 100-continueReferences
- Registry
- IANA HTTP Field Name Registry
- Guide
- MDN Expect