HTTP Header Reference
Look up request and response headers, their direction and typical values.
No header matches that
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What is the HTTP Header Reference?
HTTP headers are where caching, authentication, content negotiation, CORS and most security controls actually live. There are a lot of them, they are specified across many documents, and the ones you need are rarely the ones you remember.
This is a searchable reference: which direction each header travels, what it controls, example values that are actually correct, and notes on the security or caching implications. It is a lookup table for building requests and reviewing responses, not a specification replacement.
How to use it
- Search by header name or by what you are trying to achieve.
- Filter by direction (request or response) or by topic — caching, security, CORS, content negotiation.
- Open a header for example values and related headers.
Example
Looking up Cache-Control.
cache-control
Cache-Control — request and response Directs caching behaviour for both shared and private caches. Examples public, max-age=31536000, immutable hashed static assets private, no-cache personalised HTML no-store responses containing secrets
Features
- Request and response headers, clearly labelled by direction
- Topic filters: caching, security, CORS, authentication, content negotiation
- Realistic example values, copyable individually
- Notes on deprecated headers and what replaced them
- A security-headers checklist for reviewing a response