--- layout: default ---
Header category

Connection & Transport

Headers about the connection rather than the resource: hosts, upgrades, proxies, forwarding, keep-alive.

57 headers
149 provider declarations
HeaderProvidersStatus
X-Amz-Target 58 de-facto
Connection 24 permanent
Transfer-Encoding 21 permanent
Host 8 permanent
Sec-WebSocket-Protocol 7 permanent
Upgrade 6 permanent
Priority 5 permanent
Alt-Svc 3 permanent
SoapAction 3 permanent
Topic 2 permanent
Sec-WebSocket-Key 2 permanent
Expect 2 permanent
Urgency 1 permanent
TTL 1 permanent
TE 1 permanent
Sec-WebSocket-Version 1 permanent
Sec-WebSocket-Extensions 1 permanent
Sec-WebSocket-Accept 1 permanent
Keep-Alive 1 permanent
Via 1 permanent
Destination permanent
Depth permanent
DAV permanent
DASL permanent
Configuration-Context provisional
Close permanent
CDN-Loop permanent
Capsule-Protocol permanent
C-PEP-Info deprecated
C-PEP obsoleted
C-Opt obsoleted
C-Man obsoleted
C-Ext obsoleted
Apply-To-Redirect-Ref permanent
Alt-Used permanent
ALPN permanent
Timeout permanent
Redirect-Ref permanent
Proxy-Status permanent
Proxy-Instruction obsoleted
Proxy-Features obsoleted
Protocol-Request obsoleted
Protocol-Query deprecated
Protocol-Info deprecated
Protocol obsoleted
PEP-Info obsoleted
PEP obsoleted
Overwrite permanent
Opt obsoleted
Max-Forwards permanent
Man obsoleted
Incremental permanent
HTTP2-Settings obsoleted
Forwarded permanent
Ext obsoleted
Early-Data permanent
Trailer 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=transport&limit=10"
Everything under a tag
curl "https://apis.io/api/v1/tags/transport"

Discovery needs no key. Ratings and market analysis are Pro.

Get an API key

Free tier, no form to fill in. Signing in shares your email address with us — we store it to create your key and to recognise you if you sign in with another provider. See our Privacy Policy and Terms.

A second provider on the same verified email joins the account you already have.