--- layout: default ---
Header category

Content Negotiation

Headers through which client and server agree on representation: media type, language, encoding, character set.

27 headers
386 provider declarations
HeaderProvidersStatus
Accept 253 permanent
Accept-Language 90 permanent
Accept-Encoding 39 permanent
Accept-Charset 3 deprecated
Accept-Datetime 1 permanent
GetProfile obsoleted
EDIINT-Features provisional
Differential-ID deprecated
Dictionary-ID permanent
Derived-From obsoleted
Delta-Base permanent
Available-Dictionary permanent
Alternates permanent
Accept-Signature permanent
Accept-Query permanent
Accept-Post permanent
Accept-Patch permanent
Accept-Features permanent
Accept-CH permanent
Accept-Additions permanent
A-IM permanent
Use-As-Dictionary permanent
TCN permanent
SetProfile obsoleted
Negotiate permanent
IM permanent
Variant-Vary permanent

All categories

Authentication Authorization & Scope Caching Conditional Requests & Concurrency Content Negotiation Representation Metadata Connection & Transport CORS Security Policy Privacy & Consent Rate Limiting & Quota Tracing & Correlation Idempotency & Reliability Versioning & Lifecycle Integrity & Signing Async & Long-Running Cost & Metering Agent & Bot Identity

Work with this as data

Every header here is available over the APIs.io API and to AI agents over MCP. HTTP Headers is not yet its own endpoint on the v1 API. Reach it through catalog search and the tag graph, or the MCP server.

MCP server

One button, every client — Claude, Cursor, VS Code and the rest.

https://apis.io/mcp

Tools for http headers

3 MCP tools reach this
  • apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
  • resolveTurn a domain, URL or GitHub org into the provider it belongs to.
  • find_cohortsEvery scored population of providers in the catalog.
All 92 tools →

Call it yourself

curl for this page
Search the catalog
curl "https://apis.io/api/v1/search?q=negotiation&limit=10"
Everything under a tag
curl "https://apis.io/api/v1/tags/negotiation"

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