Companies House Open Data: How the Open Government Licence Powers Tools Like qxx.uk

The UK Government publishes vast quantities of public data under the Open Government Licence (OGL) v3.0, maintained by The National Archives. Companies House, HMRC, and the Office for National Statistics all publish data under this framework, and tools like qxx.uk are built on top of it. If you use UK corporate data, understanding the OGL — what it permits, what it requires, and what it restricts — is essential.

What the Open Government Licence is

The OGL v3.0 is a free, open licence allowing anyone to copy, distribute, transmit and adapt the licensed material for commercial purposes, without fee or specific permission. The key conditions are:

• Attribution. You must acknowledge the source. For Companies House data, state that data comes from Companies House under the OGL v3.0.
• Crown copyright. The data remains Crown copyright but the OGL grants a perpetual, royalty-free licence to use it.
• No endorsement. You must not suggest the UK Government endorses your product or service.
• No warranty. Data is provided "as is" without warranty as to accuracy, completeness, or timeliness.

How Companies House makes data available

• Public register. The free web interface allows individual lookups by company name, number, or director name — the simplest route for a single check.
• API. The Companies House API provides programmatic access to company profiles, officers, filings, charges, and search results. Free for low-volume use (up to 600 requests per 5 minutes); high-volume access requires a free API key. The API returns JSON and is the primary route for automated compliance tools.
• Bulk data. Periodic bulk data files (company snapshots, officer lists, charge data) are available for large-scale analysis and local database building.

What you can do with the data

Under the OGL, you can: build a lookup tool that displays Companies House data to users; integrate the data into internal compliance or procurement systems; build dashboards, reports and alerts; resell services incorporating the data (with attribution); and use the data for academic research, journalism or public interest purposes.

What you cannot do: present data in a way implying Government endorsement; claim copyright over the raw data itself (though you can copyright your creative expression in how you present it); use the data for unlawful purposes; or re-distribute it imposing additional restrictions beyond those in the OGL.

The HMRC VAT lookup and its terms

The HMRC VAT lookup is a free, real-time query service: send a VAT number, receive the registered business name and address. The OGL applies to the output, but HMRC does not provide a bulk API; the lookup is designed for individual checks. Tools like qxx.uk query the HMRC service in real time and cache results for a reasonable period to stay within rate limits.

Postcodes.io and ONS data

Postcodes.io is a free, open-source API providing UK postcode data sourced from the Office for National Statistics. It returns the district, local authority, region, country, constituency, NHS area, NUTS codes and coordinates under the OGL. It is the standard route for postcode-based lookups in UK applications, free for unlimited use subject to reasonable rate limits.

Why open data matters for compliance

The combination of open data, the OGL, and free APIs means basic UK corporate due diligence is accessible to any business regardless of size. You do not need an expensive data licence to check a company's status, verify a VAT number, or look up a postcode. The cost of compliance has dropped to where a 60-second check before placing an order is the minimum standard. Tools like qxx.uk exist because the OGL makes it possible — and because the public has a right to access the data the Government holds on its own companies. Understanding the OGL also protects your business: if you use UK public data in your products, you know your obligations and can build a workflow that respects them while delivering real value.