Built for AI builders

Give your agent real UK company intelligence

DataLedger turns Companies House filings into structured financial data your AI can actually use. Look up companies, filter by financials, build apps - all through a clean REST API.

Get free credits → Get the system prompt
// Agent querying DataLedger

GET /v1/companies/09876543

// Response
{
  "companyName": "Acme Creative Ltd",
  "isActive": true,
  "employees": 12,
  "financials": {
    "cTurnoverRevenue": 1840000,
    "cProfitLoss": 312000,
    "assetsGrowthRate": 0.18
  }
}

✓ 1 credit used  ·  24 remaining
5M+
UK companies
3
API endpoints
25
Free credits to start
98%
Electronic coverage (micro entity)
What you can build

Company data your agent can act on

DataLedger is designed to be a data layer, not a dashboard. Query it directly from your agent, workflow, or application.

⚡
Automated company research
Give your agent a list of company names. It resolves each to a Companies House number, pulls the financial profile, and returns structured data ready to process, score, or present.
🔍
Prospect discovery workflows
Search by SIC code, location, employee count, and financial thresholds to surface companies matching your criteria. Filter to active, non-dormant, electronically filed records for the best data quality.
📊
Enrichment pipelines
Pass a CRM or spreadsheet of company numbers through the API to append financial data - turnover, equity, growth rates, employee count, registered address - all in a single call per company.
🤖
AI-native applications
Build products where users ask questions about businesses in plain English. Your agent queries DataLedger in the background and surfaces the answer - no spreadsheets, no manual lookups.
📋
Due diligence assistants
Combine company profile, financials, and growth trends in a single automated report. Useful for M&A screening, credit assessment, supplier checks, or any workflow that currently involves manual Companies House searches.
🗂
Market intelligence tools
Query by sector and geography to map competitive landscapes, track industry trends, or identify market size. Use the meta endpoint to count matching companies before pulling the full dataset.
How it works

Three things your agent can do

The API has three endpoints. Most workflows use all three together.

01 — FIND
Resolve a name to a number
If you have a company name but not its Companies House number, the autocomplete endpoint returns matches instantly. Use this as the first step before any profile lookup.
GET /companies/autocomplete
?name=acme+creative
02 — LOOKUP
Retrieve a full company profile
Pass a company number and get back registration details, SIC codes, address, employee count, and financial summary in one call. Add financials=true for the full balance sheet and P&L breakdown.
GET /companies/09876543
GET /companies/09876543?financials=true
03 — SEARCH
Filter for lists of companies
Combine filters - sector, location, employee count, financial thresholds, incorporation date - to build a targeted list. Paginate through results and enrich each company with a profile call.
GET /companies/search
?sic=62020&localAuthority=Westminster
What's in the data

Structured financials from official filings

Every field is parsed from Companies House electronic submissions - the same source of truth used by accountants, banks, and regulators.

Company registration
Name, number, status, type, incorporation date, SIC codes with descriptions, registered address, local authority
Financial summary
Total assets, liabilities, equity, turnover, profit/loss - current and prior year. Included in every basic profile call.
Calculated ratios & growth
Debt-to-equity, debt-to-asset, assets growth rate, net assets growth rate - derived from filed figures.
Full balance sheet (optional)
Cash, debtors, creditors, fixed assets, intangibles - full line items for current and prior year. Add financials=true.
Profit & loss (optional)
Turnover, gross profit, operating profit, net profit, wages - for companies that filed full accounts. Add financials=true.
Filing metadata
Accounts category, last accounts date, electronic submission flag, verification status, period covered.
Basic profile
financials=true
Search result
{
 "companyName": "Acme Creative Ltd",
 "isActive": true,
 "incorporationDate": "2018-03-14",
 "employees": 12,
 "industry": {
  "sic1": 74100,
  "sic1Description": "Specialised design"
 },
 "registeredAddress": {
  "postcode": "EC1A 1BB",
  "localAuthority": "City of London"
 },
 "financials": {
  "cTurnoverRevenue": 1840000,
  "cProfitLoss": 312000,
  "cCalculatedEquity": 428000,
  "assetsGrowthRate": 0.18,
  "cVerified": "true"
 }
}
// financials object restructured
"financials": {
 "ratios": {
  "cDebtToEquityRatio": 0.84,
  "assetsGrowthRate": 0.18
 },
 "balanceSheet": {
  "currentYear": {
   "cashBankOnHand": 94000,
   "debtorsCurrent": 310000,
   "creditorsCurrent": -218000,
   "propertyPlantEquipment": 62000
  }
 },
 "profitAndLoss": {
  "currentYear": {
   "turnoverRevenue": 1840000,
   "grossProfitLoss": 980000,
   "wagesSalaries": 540000
  }
 }
}
// Search result - no financials included
{
 "companyNumber": "09876543",
 "companyName": "Acme Creative Ltd",
 "isActive": true,
 "entityDormant": false,
 "hasPLFigures": true,
 "incorporationDate": "2018-03-14",
 "endDateForPeriodCoveredByReport":
   "2023-12-31",
 "sicCodes": ["74100"],
 "registeredAddress": {
  "postcode": "EC1A 1BB",
  "localAuthority": "City of London"
 }
}
Ready to use

Drop this into your agent

Copy the system prompt below into your AI tool - n8n, Make, Zapier, a custom GPT, or any agent framework. Replace the highlighted line with your API key and your agent is ready to query UK company data.

System prompt — replace the highlighted line with your API key

You have access to the DataLedger API, which provides financial and registration data for UK companies sourced from official Companies House filings. Use this API whenever the user asks you to look up a UK company, find companies matching certain criteria, or retrieve financial information such as turnover, assets, profit, or employee numbers.

API KEY: replace this entire line with — x-api-key: [paste your key here]. Include this header on every request. Get your key from the API Keys section at hub.dataledger.uk.

Base URL: https://api.dataledger.uk/v1

CAPABILITY 1 - LOOK UP A SPECIFIC COMPANY: GET /companies/{companyNumber} where companyNumber is exactly 8 digits (may start with a zero). Returns company name, status, type, incorporation date, registered address, SIC codes with descriptions, employee count, accounts dates, and financial summary (assets, liabilities, equity, profit/loss, turnover, ratios, growth rates) for current and prior year. Cost: 1 credit. Add financials=true for full balance sheet and P&L line items - only use if genuinely required as this costs 2 credits. If a company has not filed electronically the financial fields will be null but the company profile is still returned.

CAPABILITY 2 - SEARCH FOR COMPANIES BY CRITERIA: GET /companies/search with filters - name (partial), sic (5-digit), postcode or prefix, localAuthority, isActive (true = active only), entityDormant (false = exclude dormant), incorporationDateFrom / incorporationDateTo (YYYY-MM-DD), minEmployees / maxEmployees, minEquity / maxEquity / minTotalAssets / maxTotalAssets / minTotalLiabilities / maxTotalLiabilities (GBP), hasPLFigures (true = best data quality when using financial filters), limit (max 50), offset (for pagination), meta=true (count only, no results). Cost: 1 credit. Search results include company details but not financials - use Capability 1 to enrich individual results.

CAPABILITY 3 - FIND COMPANY NUMBER FROM NAME: GET /companies/autocomplete?name={partial}&limit=5. Minimum 3 characters. Returns matching companies with names and numbers. Use before Capability 1 if you only have a name. Cost: ~0.04 credits.

Always monitor credits via the X-API-Key-Details response header. Paginate search results by incrementing offset by limit until offset exceeds totalCount. Default to the basic 1-credit profile call unless the user specifically needs detailed line items.

Where to paste it: In n8n use the System Message field in your AI Agent node. In Make or Zapier look for System Prompt or Instructions in the AI step. In a custom GPT paste into the Instructions box.
Machine-readable spec

Full API reference for AI tools

A clean markdown spec covering every endpoint, parameter, field, and response shape - formatted for LLMs and agent frameworks rather than human readers.

DataLedger API Spec

Complete reference covering all three endpoints, every query parameter with types and examples, full response schemas for both basic and detailed modes, error codes, and usage guidance for agents. No marketing copy - just the spec.

Markdown LLM-optimised v1.0
Download spec →

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