Understanding the Companies House API: A Non-Technical Guide

What Is the Companies House API?

Companies House is the UK government body responsible for incorporating and dissolving limited companies, registering company information, and making that information available to the public. The API is free to use — you need only a free API key from the Companies House developer hub.

What Data Is Available

The Companies House API exposes company profiles, officers, persons with significant control, filing history, insolvency records, and an advanced search endpoint for filtering by incorporation date, company type, and status.

The Advanced Search Endpoint

For most lead generation and market research use cases, the advanced search endpoint is the most useful. It lets you query all companies incorporated within a date range, filtered by company type and status.

Rate Limits and Bulk Access

The free tier allows 600 requests per 5 minutes. For bulk data access, Companies House provides a separate bulk data download service with large ZIP files containing pipe-delimited text files.