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Allow

IANA permanent response RFC 9110 2 spellings

Declared by 6 providers across 14 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.

Allowallow

The registry

Statuspermanent
ReferenceRFC 9110, Section 10.2.1: HTTP Semantics

Providers declaring it (6)

euler gs1 lufthansa-cargo pydantic-ai upwind upwind-security

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