About this API
Companies House is the UK equivalent of the KRS — the register of all companies incorporated in the United Kingdom. Its public REST API returns company data, officers and filings by company number. It is one of the most searched government company registers in the world.
Frequently asked questions
Do I need an API key?
Yes — it requires a free API key (register on the developer portal); the key is sent via Basic auth.
What data does this API return?
A UK company's data by number — name, status, address, officers, filing history and documents.
Can this API be called directly from a browser?
Not easily — key/registration-based authentication requires a server-side call and is not suitable for frontend code visible to visitors (which is why there is no live "Try it" button here).
Who runs this API?
UK Companies House. Documentation: developer.company-information.service.gov.uk.