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Accept-Language

IANA permanent request RFC 9110 2 spellings

Declared by 69 providers across 2351 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 2 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.

Accept-Languageaccept-language

The registry

Status	permanent
Reference	RFC 9110, Section 12.5.4: HTTP Semantics

Providers declaring it (69)

adopets airbus-oneatlas apifreaks-api-hub-for-developers appdirect autodesk-bim360 autodesk-fusion back-market bamboo ccp-games cdk-global certifaction chaitin conekta credilinqai dow-jones ebay edamam-recipes elastic-path engineering-platform eurostat eve-online freepik genesys getty-images harver ikea keyper lean-technologies london-stock-exchange-group mastercard microsoft-azure microsoft-office-integration moneris moodys-rms morningstar mx mx-platform mx-technologies newstore okta oracle-e-business-suite oracle-hospitality palenca-vech patch-io politecnico-di-torino quandoo ripe-insurance rwth-aachen-university smart-pension smartnews tapcart tickitto top-group transitapp treadio tribe-payments uphold viator visa visier wallapop who wikimedia wikipedia wikisource wiktionary wise zamna zhipu-ai

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