HTTP foundations ยท XB Field Noteshttps://www.xbcatm.com/series/http-foundations/Illustrated field notes on HTTP, DNS, TLS, Caddy, SSH, releases, and recovery.Hugoen-usContent-Type should describe the bytes you actually sendhttps://www.xbcatm.com/notes/content-type-should-describe-the-bytes-you-actually-send/Sun, 23 Aug 2026 00:00:00 +0000https://www.xbcatm.com/notes/content-type-should-describe-the-bytes-you-actually-send/Check media types at the public edge and use nosniff to make mismatches fail visibly.HEAD should describe the same representation as GEThttps://www.xbcatm.com/notes/head-should-describe-the-same-representation-as-get/Sun, 23 Aug 2026 00:00:00 +0000https://www.xbcatm.com/notes/head-should-describe-the-same-representation-as-get/Compare HEAD and GET metadata without confusing a missing body with a different resource.Range requests should prove which bytes were selectedhttps://www.xbcatm.com/notes/range-requests-should-prove-which-bytes-were-selected/Sun, 23 Aug 2026 00:00:00 +0000https://www.xbcatm.com/notes/range-requests-should-prove-which-bytes-were-selected/Verify partial responses, Content-Range, and the behavior of unsatisfiable byte ranges.Cache headers are a contract with two clockshttps://www.xbcatm.com/notes/cache-headers-are-a-contract-with-two-clocks/Sat, 22 Aug 2026 00:00:00 +0000https://www.xbcatm.com/notes/cache-headers-are-a-contract-with-two-clocks/Choose freshness and revalidation rules from how often a representation can change.Compression changes the selected HTTP representationhttps://www.xbcatm.com/notes/compression-changes-the-selected-http-representation/Sat, 22 Aug 2026 00:00:00 +0000https://www.xbcatm.com/notes/compression-changes-the-selected-http-representation/Treat content encoding, validators, and Vary as one observable response contract.Redirects and error codes should preserve the storyhttps://www.xbcatm.com/notes/redirects-and-error-codes-should-preserve-the-story/Sat, 22 Aug 2026 00:00:00 +0000https://www.xbcatm.com/notes/redirects-and-error-codes-should-preserve-the-story/Use permanent redirects and absence codes to describe what happened, not to hide a broken route.robots.txt and sitemaps answer different questionshttps://www.xbcatm.com/notes/robots.txt-and-sitemaps-answer-different-questions/Sat, 22 Aug 2026 00:00:00 +0000https://www.xbcatm.com/notes/robots.txt-and-sitemaps-answer-different-questions/Keep crawler preferences, URL discovery, and access control separate.