Avoid using too many response headers

What are headers?

Headers are information attached to HTTP requests and responses that tell web servers and browsers how to process the requests or responses. Headers control everything from how long content should be cached to where the request for proxied content comes from. Headers do count as data that must be sent to web servers or to visitors’ web browsers.

Why are long headers a problem?

Many web servers and content-delivery networks (CDNs) have limits on how large response headers can be. If the web page sets too many or too large response headers, the web page may not load properly or completely for users.

What to do about long headers?

For most websites, this is not usually a problem, especially when using WordPress or another content management system. If the website is sending too long headers, the website will have to be changed to consolidate headers or to send fewer headers. For WordPress websites, generally limiting the number of installed plugins, especially plugins that provide similar or the same functionality, can help keep headers from being a problem.