103

Early Hints

Official

The server prepares a response

General explanation of the 103 status code

Imagine you go to a restaurant and order a menu. Instead of waiting for the entire menu to be served at once, the waiter already gives you an appetizer while the rest of the meal is being prepared. This allows you to start eating already instead of waiting idly.

The 103 Early Hints Early Hints status code works the same way. When a server receives a request from your browser to load a web page, it can sometimes take a while to compile all the information it needs. Instead of making your browser wait, the server can use the 103 Early Hints code to give "early hints" about the resources that will be loaded soon. This means that your browser can start loading certain parts of the page, such as stylesheets or scripts, even before the server's entire response is complete.

This type of communication makes the overall web page load time more efficient and faster, since the browser and the server are working at the same time, rather than one after the other. It is as if they are working together as a team to present you the information as fast as possible.

So, the 103 Early Hints Early Hints status code is a tool that helps to improve the speed and efficiency of the Internet. While it may not be as well known as other codes, it still plays an important role in making the web a faster and smoother experience for all of us.

Specification of the HTTP status code 103

The HTTP-103 Early Hints information response can be sent by a server while it is still preparing a response, with hints about the resources that the server is expected to link in the final response. This allows a browser to start preloading resources even before the server has prepared and sent the final response. The Early Hint Response is primarily intended for use with the Link header, which specifies the resources to be loaded. It may also contain a Content-Security-Policy header that is enforced when the Early Hint is processed. A server may send multiple 103 Early Hints responses, for example after a redirect. Browsers process only the first response of the early notice, and this response must be discarded if the request results in a cross-origin forwarding. Preloaded resources from the early hint are effectively prepended to the head element of the document and then followed by the resources that are loaded in the final response.

Source / Quote by: The 103 Early Hints HTTP Status Code is specified by section 2 of RFC8297.

HTTP-Protocol

Experimental

How to throw a 103 statuscode with PHP?

To throw the HTTP status code 103 on a web page, the PHP function http_response_code can be used. The syntax is as follows: http_response_code(103) (PHP 5 >= 5.4.0, PHP 7, PHP 8)

Test the 103 HTTP status code

http-statuscode.com (Test Status code 103)

httpstat.us (Test Status code 103)

In order to be able to display the HTTP status code (in this case 103 Early Hints) and other information on the client side, the development console must be opened with F12. Afterwards you have to navigate to the tab "Network". Now you can open the page, in the network tab you should see the web page (example index.php). This must be selected and then the Herder section must be selected. Here the user will see the following result:

Overview
URL: https://http-statuscode.com/errorCodeExample.php?code=103
Status: 103 Early Hints
Those: Network
IP address: XX.XX.XX.XX

Browser compatibility of the 103 status code

Chrome	Yes
Edge	Yes
Firefox	Yes
Opera	No
Safari	No
Chrome Android	Yes
Firefox for Android	no data
Opera Android	No
Safari on iOS	No
Internet	no data
WebView Android	no data