How to Avoid Large HTTP/1 Response Headers

Websites will often attach information known as response headers to the data the websites send back to visitors’ browsers. Response headers contain additional information for the web browser to use to enhance the website experience for the visitor. This information includes, but is not limited to, caching headers, data encoding headers, cookies, authentication tokens, and other useful information that should not be included in the web page’s content directly. All of this information must be downloaded on each page by the web browser alongside the actual web page content.

Unfortunately, large numbers of cookies and other response headers can significantly increase the amount of data a visitor’s web browser will download for every page view on a website. This information generally cannot be cached by web browsers and is sent each time a user loads a page. Websites using web servers with only HTTP/1 support send the response headers uncompressed, even if the rest of the web page data is compressed. Websites should set the minimum number of response headers for each web page for each visitor and reduce total page size, whenever possible, to keep the amount of information each visitor has to download as low as possible. Using HTTP/2 instead can improve website loading performance by allowing web servers to compress response headers before sending them to the visitor’s web browser.