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apikey

de facto — unregistered request 6 spellings

Declared by 94 providers across 1973 published specification files in the APIs.io network.

What this header is for, and how to use it →

A count here is providers whose published contract declares this header — not providers who send it. Response headers set at the edge rarely appear in an OpenAPI at all, so a low number can measure documentation practice rather than deployment.

Spelled 6 ways

HTTP field names are case-insensitive (RFC 9110 §5.1), so every spelling below is the same header on the wire. A contract is not the wire: generated clients key off the string, and a developer reading two of these sees two different headers.

apikeyapiKeyApiKeyAPIKeyAPIKEYApikey

Providers declaring it (94)

adobe-suite advancedmd africastalking aramark attomdata bharti-airtel braiins-academy cellulant centene cflow charityapi checkiday-national-holiday-api clari cloudmersive cloudprinter clover cms cohesity cometchat coresignal crunchdao currencyapi currencylayer department-of-veterans-affairs deutsche-bank docsumo dtn figure-technology-solutions fixer fleetmon freecurrencyapi gameball gather golden golden-recursion gupshup hacknotice hanko infoway-real-time-market-data-api inspectorio jotform kpn kraken kuehne-nagel la-poste landingai layup-technologies lufthansa-cargo maven-machines meltwater moogsoft nagios nansen nerdio nirvana nist novopayment numlookupapi nvd ondemand orange-business ozow placekey postnl pruna-ai recreation-gov rsc samu sap-brim-billing-and-revenue-innovation-management schema-free scispot sikoia snowsignals songstats sorsa spectro-cloud supabase swish-analytics teachable ticketspice transit tricentis twelvedata tyntec university-of-minnesota va va-gov veho viator vinculum visier xoserve zenscrape zenserp

Explore

All headers Authentication Guidance on headers.apievangelist.com

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

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

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