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
Each result includes a confidence level, so you can decide how much to trust it. See the response reference for what every field contains.
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.
Versioning
The
/api/v1 contract, the release number, and what counts as breaking.Changelog
Material changes to the API, newest first.
Base URL
/api/v1/match. The interactive playground on each endpoint page lets you paste your API key and send live requests.