--- layout: default ---

x-client-id

de facto — unregistered request 4 spellings

Declared by 46 providers across 378 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 4 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.

x-client-idX-Client-IdX-CLIENT-IDX-Client-ID

Providers declaring it (46)

airwallex aldermore att bank-of-ireland-uk bank-of-scotland blockaid bmo bud-co cashfree chargetrip chase-uk cofactr coutts coventry-building-society cynergy-bank epa fabric-com first-direct gb-bank gsma hampden-and-co hometrack ikea intelycare investec jp-morgan-chase kroo kyber-network lloyds-banking-group mesh mesh-connect monument-bank open-banking-uk oura paragon-bank parseflow plug recognise-bank santander-uk secure-trust-bank shawbrook-bank tandem-bank telkomsel thirdweb tribe-payments visa

Explore

All headers Authentication Guidance on headers.apievangelist.com