Integration in 10 minutes
Follow these steps to go from zero to a working API call. All examples use Tesco PLC (company number 00445790) as the reference company.
Register and get your API key
~2 min
Enter your email to get a free API key. No credit card required. Your key arrives in your inbox within seconds.
Your key will look like: reg_live_a1b2c3d4e5f6...
Free tier: 50 calls per month, all endpoints available. No expiry.
Get your free key →Make your first call
~3 min
Fetch an enriched company profile. We'll use Tesco PLC (00445790) as the example — a large, well-documented company with full accounts.
curl -H "X-API-Key: reg_live_YOUR_KEY_HERE" \
"https://api.registrum.co.uk/v1/company/00445790"Uses the demo key. Results are real data from the Companies House API.
Understand the response
~2 min
Every response is wrapped in an APIResponse envelope. Hover over the fields below to see what's enriched vs raw.
{
"status": "success",
"cached": true, // served from cache — no CH API call made
"credits_remaining": 49, // your monthly quota remaining
"data": {
"company_name": "TESCO PLC",From CH API
"company_number": "00445790",From CH API
"company_status": "active",From CH API
"company_age_years": 78,Computed by Registrum
"accounts": { "overdue": false, "next_due": "2024-07-24" },overdue boolean computed
"sic_codes": ["47110"],From CH API
"cached": true,Infrastructure metadata
"credits_remaining": 49,Your quota remaining
}
}
Add financials
~2 min
The /financials endpoint parses the company's iXBRL filing and returns structured financial data — revenue, profit, net assets, employees — as clean JSON. No XBRL parsing required.
Financials are cached for 7 days. The response includes a data_quality object explaining exactly what was extracted and what wasn't available.
curl -H "X-API-Key: reg_live_YOUR_KEY_HERE" \
"https://api.registrum.co.uk/v1/company/00445790/financials"{
"accounts_type": "full",
"period_end": "2024-02-24",
"profit_and_loss": {
"turnover": { "current": 68190000000 },// £68.19 billion
"profit_after_tax": { "current": 1400000000 }
},
"balance_sheet": { "net_assets": { "current": 10700000000 } },
"other": { "employees": { "current": 295622 } }
}
Financial data is only available for companies that file digitally. Micro-entities and dormant companies return limited balance sheet data only. See the financial data example →
Deploy to production
~1 min
Store your API key in an environment variable. Never hardcode it in source code or commit it to Git.
# Set the env var in your shell:
export REGISTRUM_API_KEY="reg_live_YOUR_KEY_HERE"
# Then use it:
curl -H "X-API-Key: $REGISTRUM_API_KEY" \
"https://api.registrum.co.uk/v1/company/00445790"Rate limits
Every response includes credits_remaining. A 429 response means you've hit the monthly limit or burst rate. Upgrade your plan to increase both.
Error handling
All error responses include status: "error" and a human-readable detail. On CH API outages, cached data is served with the X-Data-Stale header — your app stays live.
Director network
GET /v1/company/{number}/network?depth=1 returns all companies sharing directors. Depth 2 traverses one level further. Cached 24h.
curl -H "X-API-Key: reg_live_YOUR_KEY_HERE" \
"https://api.registrum.co.uk/v1/company/00445790/network?depth=1"Need more calls?
Free tier: 50 calls/month. Starter (£19/mo): 500 calls. Pro (£49/mo): 2,000 calls. Enterprise (£149/mo): 10,000 calls. All plans include all endpoints.
View pricing →Ready to integrate?
Full API reference in Swagger — every endpoint, every parameter, try it live.