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Header category

CORS

The cross-origin negotiation. A small, closed set of headers that decide whether a browser is allowed to see a response it already received.

13 headers
125 provider declarations
HeaderProvidersStatus
Access-Control-Allow-Origin 41 permanent regulated
Access-Control-Allow-Methods 22 permanent
Access-Control-Allow-Headers 20 permanent
Origin 16 permanent
Access-Control-Allow-Credentials 15 permanent
Access-Control-Expose-Headers 6 permanent
Access-Control-Max-Age 2 permanent
Access-Control-Request-Method 1 permanent
Timing-Allow-Origin 1 provisional
Access-Control-Request-Headers 1 permanent
Access-Control obsoleted
Method-Check obsoleted
Method-Check-Expires obsoleted

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=cors&limit=10"
Everything under a tag
curl "https://apis.io/api/v1/tags/cors"

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