HTTP headers are key-value pairs sent between a client (browser) and a server during every HTTP request and response. They carry metadata that controls caching, security policies, content types, and much more.

• Security headers like Content-Security-Policy and Strict-Transport-Security protect your site from common attacks such as XSS and man-in-the-middle.
• Caching headers (Cache-Control, ETag) improve page speed and reduce bandwidth by instructing browsers and CDNs how long to store resources.
• SEO-relevant headers (Content-Type, X-Robots-Tag) ensure search engines correctly interpret and index your content.

Regularly auditing your HTTP headers helps maintain strong security postures, faster load times, and better search engine visibility.