Commercial use of API

What are the rules regarding commercial use of the API? I assume it’s allowed but I cannot find any terms of use or conditions document about using the API online. There was something on the HMRC Developer Hub but I saw that Companies House is technically separate to HMRC so I don’t know if it applies.

Essentially, if I use this API to generate income as part of a business, what do I need to do? Do I need to register somewhere, or are there some rules that need to be followed.


@jimYour assumption is correct - there is nothing in the documentation that restricts commercial use.

You will find the T&C of use of the Companies House API here:

The guidelines can be summarised as follows:

API rate limits - You can make up to 600 requests within a 5 minute period.

API key security:

  • Do not embed API keys in your code
  • Do not store API keys in your source tree
  • Restrict API key use by IP address and domain
  • Regenerate your API keys
  • Delete API keys when no longer required

If you use the API to generate income as part of a business, you will need to register the business with either Companies House or HMRC depending on the nature of ownership of your business: Set up a business - GOV.UK

If you wish to run your business as a limited company or LLP, you will need to register with Companies House.

However if you wish to operate as a sole trader or a traditional partnership, you will need to register for self assessment with HMRC. Register for Self Assessment: Register if you’re self-employed - GOV.UK