How to Enable Save-Data HTTP Header in Firefox

With time new web technologies are bring introduced some of which give us more features while some make our life easier as we use the internet. Recently a new feature has been added to the HTTP header set called Save-Data. This header field is a request sent to the web servers to serve a version of the website which consumes the least possible data for the client.

What this means is that if a user wants to browse a website that has lots of high-resolution pictures and other data consuming content, but also wants to save the data, then they can send a request Save-Data:ON. When this request header is honored by the web server, they will avoid sending any rich content. But this works only if the web server actually honors this request. You can find details about this from

So how do you enable Save-Data:On? As of now, it appears not to be available through the settings interface of any web browser so as to toggle this feature on or off. But with the help of an extension called “Save-Data: on” we can enable it automatically. This extension has no settings. Just by installing this extension, it starts to work.

"Save-Data: On" Extension

After you have installed “Save-Data: on” extension, every single HTTP request from your web browser will get “Save-Data: on” appended to it. This can drastically reduce the data downloaded as you visit websites everyday.

You can use the developer tools in either Firefox or Chrome browsers (this “Save-Data: on” extension is available for both of them), you can see the request headers in real-time.

"Save-Data: On" Extension

For this, you can press the F12 button on your keyboard and then reload the website. In the developer tools interface, you have to switch to the Network section. After this you can click on any downloaded file through a GET request and check for its request headers. You should be able to locate “Save-Data: On” request.

You can get the “Save-Data: On” extension for Firefox browser from and for Chrome web browser from