HTTP 103 Early Hints

The server sends preliminary headers before the final response.

Use 103 to send Link preload or preconnect hints while the final response is being prepared.

httpstatus codeinformationalperformance

Response (http)

HTTP/1.1 103 Early Hints

Use 103 to send Link preload or preconnect hints while the final response is being prepared.

Common mistakes

Putting final headers or a body into 103; it may only carry provisional Link hints.

Registry reference: rfc8297

Sources