Government — entry 089 of 90
UK Companies House
The public Companies House API exposes UK company registration data — profiles, officers, filing history, persons with significant control, and charges — free of charge. A live keyless request against `api.company-information.service.gov.uk` returned a `401` with `access-control-allow-origin: *`, confirming the read API is open to browser cross-origin calls. Despite the developer portal branding it "OAuth", the documented and primary way to call the read API is HTTP Basic auth with a free API key as the username; OAuth2 is a separate flow reserved for the restricted filing/account-linking scopes.
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<a href="https://greatapis.com/api/uk-companies-house/"><img src="https://greatapis.com/badge/uk-companies-house.svg" alt="Scored 78 on greatapis.com"></a>Auth quickstart
- Sign up with the provider to get an API key.
- Send it on every request as a header
Authorization: <key> - The exact header isn't documented — Authorization is a common default; confirm in the provider's docs.
Your key is stored only in this browser (localStorage) and sent directly to the API — never to greatapis.
Developer reference
600 requests per 5-minute period, per application/API key