HTTP header

An HTTP header is a piece of information sent invisibly alongside a web page or other resource, as part of the request or response. Headers let browsers and servers exchange instructions - such as how long to cache a page, what type of content it is, or what security rules to apply - without changing anything visitors see.

Several headers matter for how Silktide and search engines treat a page: Last-Modified reports when content changed, X-Robots-Tag can apply a noindex rule without touching the page's HTML, and Cache-Control governs caching alongside CDN behavior.

Learn more

• HTTP header fields - the RFC 9110 specification
• Cache
• Last-Modified
• Noindex