HTTP Header Reference

Search a curated list of the HTTP headers you actually meet day to day and read a short, plain explanation of what each one does and whether it is used on requests, responses or both. Type a word like cache, cors, security or content to filter the list down to the relevant headers. HTTP has a large and ever growing set of headers, and it is easy to forget exactly what a given one controls, so a quick searchable reference saves a trip to the specification when you are debugging caching, CORS, authentication or security policies. Each entry notes the typical direction so you know whether to set it on the client or the server. The whole list is built into the page, so it works instantly and offline, and nothing you search for is ever sent to a server.