📋 Inspecting HTTP Response Headers

Cache policy, server details, and compression, all from one set of headers.

Curious how long a website caches its content, or what server software it runs? The HTTP response headers tell you.

Common headers and what they mean

Content-Type (the response's data format), Cache-Control (caching policy), Server (the server software, often hidden for security), Set-Cookie (cookies being set), and Content-Encoding (whether gzip or similar compression is used) are the ones you'll check most often.

Reading cache-related headers

Cache-Control: max-age=3600 means the browser can reuse its cached copy for an hour without re-requesting. no-store forbids caching entirely. ETag and Last-Modified are used for conditional requests that can return a 304 Not Modified.

Common use cases

This is useful for checking whether static assets are cached correctly to improve site speed, judging whether a CDN is in front of a site via headers like x-cache or cf-ray, and checking rate-limit headers on an API response.

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