This post is by CompanyData.com, a company data provider built on official registers and one of the five alternatives below. Keep that in mind while reading.
We built this because the register leaves out two things our customers kept asking for: someone to call, and the businesses that never had to register in the first place. Companies House holds 5.5 million incorporated entities and no contact details at all, where our UK file holds 8,852,655 records including sole traders and branches, with a phone number on 2.7 million and an email address on 1.3 million of them.
The short version: the official Companies House API is free and it is good. If all you need is UK registry lookups, use it and stop reading. Look elsewhere only when you need something the register itself does not hold.
What the official API gives you
- A free API key after you register an application on the developer hub.
- Company profile, officers, persons with significant control (PSC) and filing history.
- 600 requests per five minutes per application. Go over and every request returns 429 until the window resets.
- A streaming API for changes, and bulk snapshots for one-off lists.
# the key is the basic auth username, the password stays empty curl -u "$COMPANIES_HOUSE_KEY:" \ https://api.company-information.service.gov.uk/company/09446231 Most 401 errors come from sending the key as a bearer token instead.
What it leaves out
| You need | What the official API has |
|---|---|
| Phone, email, website | Nothing. The register does not hold contact details |
| Sole traders and partnerships | Nothing. Only incorporated entities are registrable, so about 3.1 million UK sole traders and 343,000 ordinary partnerships are out of scope |
| Employee counts | Nothing |
| Revenue as a number you can filter on | Accounts arrive as iXBRL documents, not JSON fields |
| Shareholders | Inside confirmation statement documents |
| Companies outside the UK | One country, so every other register is a separate integration |
None of this is a flaw in the API. It publishes what the register holds.
Cost, data points and number of companies
The three things that decide it, side by side with what we deliver for the UK.
| Companies House API | CompanyData.com | |
|---|---|---|
| Cost | Free | From $34 a month, 7-day trial |
| Companies | 5.5 million on the register, incorporated entities only | 8.8 million UK records, including sole traders, branches, dissolved and dormant ones. 375M+ worldwide |
| Data points per company | The register fields: name, number, address, SIC code, status, officers, PSC, filings | 50+ |
| Directors and officers | Yes, as a separate call | On 6.3 million records |
| Website | None | On 2.7 million records |
| Phone | None | On 2.7 million records, mobile on 0.9 million |
| Business email | None | On 1.3 million records |
| Revenue and employees | Inside iXBRL documents | Bands, as fields you can filter on |
| Group structure | None | Included |
| Other countries | None | 190+, same schema |
If the left column covers what you need, the official API is the right choice and it costs nothing. You pay us for the right column: more companies, more data points per company, and one integration for every country.
Five alternatives, compared
| Option | What it adds over the official API | How you buy |
|---|---|---|
| OpenCorporates | Registers from about 140 jurisdictions in one API | GBP 225 a month for 500 calls. Free for public-benefit projects |
| Creditsafe | Credit scores and payment behaviour | Annual contract through sales |
| Dun & Bradstreet | D-U-N-S numbers and credit risk | Enterprise contract |
| Moody's Orbis | Deep ownership trees and private-company financials | Enterprise contract |
| CompanyData.com (us) | Directors, phone, email, website, sole traders, and revenue and employee bands as fields, plus 190+ other countries in the same schema | From $34 a month, 7-day trial |
How we would pick
Registry lookups or form autocomplete, UK only. The official API. It is free and it is the source.
A one-off list of UK companies. The free bulk snapshot.
Credit decisions. Creditsafe or Dun & Bradstreet. That is their core.
Contact details, company size, sole traders, or the same call for other countries. CompanyData.com. The field-by-field comparison is on our Companies House API page.
Companies House counted 5,516,377 companies on the register at 30 June 2026. The UK had 5,586,835 private sector businesses at the start of 2026, of which about 3.1 million were sole proprietorships that cannot appear on the register at all. Limits and prices checked November 2026.
Code: our open-source TypeScript wrapper for UK company data is on GitHub at companydatacom/companies-house-api, next to the TypeScript SDK.
