103 Early Hints

The HTTP 103 Early Hints status code allows servers to send preliminary information before the final response. Learn how it improves performance through resource preloading.

Published 16 Jul 2026 · HTTP Status Code

What is HTTP 103 Early Hints?

The 103 Early Hints response allows a server to send early HTTP headers before the final response is ready.

It is designed to improve performance by allowing browsers and clients to begin loading required resources sooner.

Why Does 103 Early Hints Exist?

Modern websites often require additional resources such as:

CSS files
JavaScript bundles
Fonts
Images

Normally, browsers wait for the final response before discovering these resources.

With 103 Early Hints, servers can tell clients what resources will be needed while the application is still generating the final response.

Example

HTTP/1.1 103 Early Hints
Link: </style.css>; rel=preload; as=style

The browser can begin downloading resources before receiving the final response.

Common Uses

Improving page load performance
CDN optimisation
Large web applications
Resource preloading

Why Does It Matter For DevOps?

CDN configuration
Performance optimisation
Web server tuning
HTTP protocol understanding

Summary

The 103 Early Hints response improves application performance by allowing clients to start work before the final response is available.