22 UK Government APIs You Didn't Know Existed

The Hidden Goldmine of UK Government Data

The UK government publishes an extraordinary amount of data through APIs that most developers have never heard of. Beyond the well-known Companies House and ONS APIs, there are dozens of specialist endpoints covering everything from sewage discharge events to school inspection results, from broadband coverage maps to plant patent registrations.

Most of these APIs are free, licensed under the Open Government Licence v3.0, which means you can use the data in commercial applications with minimal restrictions. The main requirement is attribution — you need to acknowledge the data source. Some APIs require registration for an API key, but the keys are free and issued automatically.

The challenge isn't access — it's discovery. These APIs are scattered across dozens of government departments, each with different documentation standards, authentication methods, and data formats. The Environment Agency uses a RESTful API with JSON responses. The Land Registry has a SPARQL endpoint. DVSA requires an API key obtained through a manual approval process. Companies House uses OAuth2. Finding, understanding, and integrating all these sources is a significant engineering effort.

That fragmentation is exactly why aggregation services exist. Individually, each government API solves a narrow problem. Combined, they tell a comprehensive story about any UK company, property, or location. A single postcode can unlock flood risk data from the Environment Agency, school ratings from Ofsted, crime statistics from Police.uk, broadband speeds from Ofcom, and house prices from the Land Registry — if you know where to look and how to combine the responses.

Company and Business APIs

Companies House is the most widely used UK government API and the foundation of any company data application. The free API provides access to the register of over 5 million UK companies, including company profiles, filing history, officer appointments, and charges. You need to register for a free API key, and rate limits are generous at 600 requests per five minutes. The data is real-time — new incorporations appear within hours.

The FCA Register API covers financial services firms authorised by the Financial Conduct Authority. It's essential for KYC checks on regulated businesses — you can verify whether a firm is authorised, what activities it's permitted to conduct, and whether any enforcement actions have been taken. The API is free and doesn't require authentication, though the documentation is less developer-friendly than Companies House.

The Gazette API provides access to official government notices, including insolvency announcements, company strike-off notices, and statutory notices. This is crucial data for credit risk assessment — a company might look healthy in Companies House records but have a winding-up petition published in the Gazette. The API is free and well-documented.

HMRC's APIs cover VAT validation, tax calculations, and customs data. The VAT API lets you verify whether a VAT number is valid and retrieve the registered name and address — useful for invoice verification. The trade tariff API provides duty rates and commodity classifications for imports and exports. Both require registration through HMRC's developer hub.

The Insolvency Service API provides data on individual and company insolvencies, bankruptcy orders, and debt relief orders. Combined with Companies House director data, it's possible to build a comprehensive picture of director financial history.

Property and Environmental APIs

The Environment Agency's suite of APIs is one of the most underutilised resources in UK government data. The Flood Risk API returns flood zone classifications for any location — essential for property due diligence and insurance risk assessment. The Real Time Flood Monitoring API provides live data from thousands of river and coastal monitoring stations across England. The Bathing Water Quality API tracks water quality at designated bathing sites.

The Land Registry provides two main data access points. The Price Paid API contains every residential property transaction in England and Wales since 1995 — over 27 million records with sale price, property type, and whether it was a new build. The UK House Price Index API provides monthly price indices by region, property type, and buyer status. Both are free but require registration.

The Energy Performance Certificate (EPC) API from DLUHC provides energy efficiency ratings for domestic and non-domestic properties. With over 25 million certificates in the database, it's a powerful dataset for property analysis, energy efficiency research, and ESG assessment. The API returns the full certificate data including current and potential ratings, wall types, heating systems, and estimated energy costs.

The British Geological Survey provides geospatial APIs covering ground stability, geological hazards, and mineral resources. The GeoIndex API is particularly useful for property development — it identifies areas of potential ground instability, historical mining activity, and geological constraints. The Coal Authority has a separate API for coal mining risk in former mining areas.

Ordnance Survey, while not entirely free, offers generous developer tiers for its mapping and geospatial APIs. The OS Places API provides the most accurate address and postcode data available for the UK, and the OS Features API delivers detailed topographic data.

Specialist Government APIs

DVSA's MOT History API is one of the most popular specialist government APIs. It returns the complete MOT test history for any vehicle registered in the UK, including test results, advisory items, failure reasons, and recorded mileage. The API requires a key obtained through an application process, and it's rate-limited but free. This data powers everything from used car valuation tools to fleet management systems.

The Department for Education's API provides school-level data including exam results, Ofsted ratings, pupil demographics, and school characteristics. The Get Information About Schools (GIAS) service has a downloadable dataset and API that covers every school in England — over 24,000 establishments. This is valuable for property platforms (school catchment areas affect house prices) and education research.

The Care Quality Commission (CQC) API provides inspection results and ratings for every regulated health and social care provider in England — hospitals, GP practices, care homes, and dental surgeries. Combined with location data, you can build a comprehensive healthcare quality map for any area.

Police.uk provides the most granular crime data available in the UK. The API returns street-level crime data, police force information, neighbourhood boundaries, and crime outcomes. Data is updated monthly with a two-month lag. The neighbourhood-level detail makes it useful for property platforms and location intelligence applications.

The Charity Commission API covers the register of over 170,000 charities in England and Wales, including financial data from annual returns. The National Archives API provides access to legislation, with the full text of every UK Act of Parliament and Statutory Instrument available in structured XML format. Transport for London's unified API covers every mode of London transport with real-time arrival predictions.

How UKDataAPI Combines These Sources

Each of the APIs described above is valuable individually, but the real power comes from combining them. A property buyer doesn't just need flood risk data — they need flood risk, school ratings, crime statistics, broadband speeds, EPC ratings, and transport connectivity, all for the same postcode. A company analyst doesn't just need Companies House data — they need company registration, FCA status, Gazette notices, director histories, and court judgments, all for the same entity.

Building these cross-source integrations yourself means managing dozens of API keys, handling different authentication methods, normalising inconsistent data formats, dealing with varying rate limits, and maintaining the integration as APIs change. It's a significant engineering effort that distracts from building your actual product.

UKDataAPI handles this aggregation. Each of the 22 endpoints combines data from multiple government sources into a single, consistent response. The Entity endpoint pulls from Companies House, FCA, and the Gazette. The Location endpoint combines Environment Agency flood data, Police.uk crime data, Ofsted school ratings, Ofcom broadband data, and ONS demographics. The Property endpoint merges Land Registry prices, EPC ratings, flood risk, planning data, and geological hazards.

Beyond aggregation, UKDataAPI adds proprietary scoring that no individual government API provides. The Corporate Distress Score synthesises company filing patterns, director behaviour, and financial signals into a single risk rating. The Environmental Risk Score combines flood, air quality, and geological hazard data into an overall assessment. These scores turn raw government data into actionable intelligence.

The practical benefit is development speed. Instead of weeks spent integrating multiple government APIs, you make one API call and get enriched, scored, and normalised data back in milliseconds. Your development time goes into building features your users care about, not parsing XML from the Land Registry.