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Send a company name (optionally with a website, postcode, SIC code, or trading date) and get back the best matching UK company registration number (CRN), plus the registered name and active status.
This API is in beta. It is stable enough to build against and serves production data. Keys are issued by hand — email support@thedatacity.com to get one. Feedback now shapes what ships next.

What you get back

A single POST /match returns one result. For lists, submit a batch and poll until it completes, or pass callback_url to be notified once.

Who it’s for

Use this API when you need to attach a reliable Companies House identity to customer lists, CRM records, or enrichment pipelines.

How to get started

Quickstart

Get an API key and match your first company in a few minutes.

Authentication

Customer API keys (dm_live_…) as a Bearer token.

Response reference

Every field in the response, and when it is empty.

Batch matching

Submit up to 1,000 companies and poll for results.

Errors

Status codes, what they mean, and what to do.

Rate limits

Per-minute limits on match endpoints.

Base URL

All match endpoints sit under /api/v1/match. The interactive playground on each endpoint page lets you paste your API key and send live requests.
Last modified on August 20, 2026