UK Companies House API

Government / OAuth Advanced HTTPS
Varies by plan (check documentation)

Overview

The UK Companies House API provides official data on companies registered in the United Kingdom, including officers, filings, and financials. It uses OAuth authentication, which requires you to register for a free API key on the Companies House developer portal. This is an excellent API for building business intelligence tools, due diligence apps, or exploring UK corporate data.

💡

Beginner Tip

Register for a free API key at developer.company-information.service.gov.uk before making requests — all endpoints require HTTP Basic Auth using your API key as the username with an empty password.

Available Data

UK Companies House data via REST API
JSON-formatted response data
Requires OAuth authentication

Example Response

JSON Response
{
  "status": "success",
  "data": {
    "result": "Data from UK Companies House",
    "description": "UK Companies House Data from the UK government",
    "timestamp": "2025-01-15T10:00:00Z"
  }
}

Field Reference

company_number The unique registration number assigned to the company by Companies House.
company_name The registered legal name of the company.
company_status Current status of the company (e.g. active, dissolved, liquidation).
date_of_creation The date the company was incorporated, in YYYY-MM-DD format.
registered_office_address The official registered address of the company including street, locality, and postcode.
sic_codes Standard Industrial Classification codes indicating the nature of the company business.

Implementation Example

const url = "https://developer.company-information.service.gov.uk/";
// Replace headers or query params with the values required by this API.
const response = await fetch(url, {
  headers: {
  "Authorization": "Bearer YOUR_API_KEY"
  }
});
if (!response.ok) throw new Error(`Request failed: ${response.status}`);
const data = await response.json();
console.log(data);

What Can You Build?

Note: These code examples are AI-generated and unverified. Always refer to the official API documentation for accurate usage.

Common Errors & Troubleshooting

401 Unauthorized Missing or invalid API key in the Authorization header.
Use HTTP Basic Auth with your API key as the username and leave the password blank: curl -u YOUR_API_KEY: <url>
404 Not Found The company number you specified does not exist in the Companies House database.
Use the search endpoint first to find the correct company number before requesting detailed company data.
429 Too Many Requests The free tier allows 600 requests per 5 minutes; you have exceeded this limit.
Slow down your request rate, add delays between calls, and cache responses to avoid redundant lookups.

Matrix Score Breakdown

🌐 Reachability 30/30
⚡ Speed 5/20
🔒 Security 15/15
🛠 Developer XP 3/20
✓ Reliability 10/15

Partially tested on Apr 5, 2026

Technical Specifications

Auth OAuth
HTTPS REQUIRED
CORS UNKNOWN
Category Government
Difficulty Advanced
Verified: 2026-04-04

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