DevToolsmith

HTTP 103 Early Hints

HTTP 103 Early Hints sends Link headers early so the browser can start preloading assets while the server prepares the page. The request was received and processing continues.

Class
1xx Informational
Standard
RFC 8297
Cacheable by default
No
Safe to retry
Not applicable: this isn’t an error
Go constant
http.StatusEarlyHints

What HTTP 103 means

While the server is still building the real response (querying a database, rendering a template), it can send a 103 with Link: rel=preload or rel=preconnect headers. Chrome and other browsers start fetching the CSS, fonts or third-party connections immediately, which can noticeably improve page load times. Cloudflare and Fastly can generate Early Hints automatically.

Retrying

Not applicable: this isn’t an error.

Example response

HTTP/1.1 103 Early Hints
Link: </style.css>; rel=preload; as=style
Link: <https://fonts.gstatic.com>; rel=preconnect

Related status codes

  • 200 OK : The request succeeded and the response contains the result.
  • 100 Continue : Tells the client to go ahead and send the request body.

Other 1xx status codes

100 Continue · 101 Switching Protocols

See the full list of HTTP status codes.

Sources

Spotted a mistake? Email hello@devtoolsmith.com and we’ll fix it.

Frequently asked questions

What does HTTP 103 Early Hints mean?

HTTP 103 Early Hints sends Link headers early so the browser can start preloading assets while the server prepares the page. While the server is still building the real response (querying a database, rendering a template), it can send a 103 with Link: rel=preload or rel=preconnect headers. Chrome and other browsers start fetching the CSS, fonts or third-party connections immediately, which can noticeably improve page load times. Cloudflare and Fastly can generate Early Hints automatically.