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api-key

de facto — unregistered request 5 spellings

Declared by 92 providers across 1472 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 5 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.

api-keyApi-KeyAPI-KeyAPI-KEYApi-key

Providers declaring it (92)

aarhus aeso agave apiops-cycles-canvas applovin appyway arkham-intelligence azure-ai-foundry azure-openai banzai breeze-chms brevo bridge cdisc cityu connexpay contrast-security d3 demodesk dev-to devto discourse eindhoven-university-of-technology fincra fiserv getty getty-images greenly-earth harbin-institute-of-technology helius hong-kong-baptist-university hotelbeds hourone hypixel ideogram interhyp istock iterable kaleyra kfupm kraken lunchbox marginalia-search messaging-api microsoft microsoft-azure microsoft-azure-openai microsoft-azure-search mindbody murf national-weather-service netcracker neutrino-api new-relic noaa noaa-gov ontraport orders-api origin outdoorsy persons-api pinecone products-api prompt-armor pushpress qdrant quadrant-api queens-university-belfast respeecher ripe-insurance rocketlane rocketreach sentio shipmonk similarweb simpleanalytics smoobu soax supertokens the-predictive-index trint university-of-bath university-of-bristol university-of-groningen university-of-manchester vrije-universiteit-amsterdam weather-gov weavr worldnewsapi xiaomi yonsei zora

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