UK Companies House Change Monitor (official API)

Watch any list of UK companies and get a change event every time something moves: company name, status (active → liquidation…), registered office, SIC codes, active-officer count, accounts / confirmation-statement due dates, and new filings. Powered by the official Companies House REST API (free key). Schedule it daily or weekly and pipe change events to email, Slack or a webhook.

Built for people who monitor companies for a living:

• Credit control & finance teams — know the day a customer files for liquidation or changes its registered office, not the month after.
• Suppliers & procurement — counterparty watch across your vendor list.
• Accountants & company secretaries — accounts and confirmation-statement due dates across the whole client book, plus proof of filing the moment it lands.
• B2B sales & PE/M&A researchers — name changes, new filings and officer movements as signals.

How it works

Each run snapshots every company (profile + officers + latest filing = 3 API calls, rate-limit safe), diffs against the previous run's snapshot stored in a named key-value store in your account (companies-house-monitor-state, so it persists across scheduled runs), and pushes one dataset row per detected change:

{
    "companyNumber": "07654321",
    "companyName": "SAMPLE GROUP HOLDINGS PLC",
    "event": "companyStatus-changed",
    "field": "companyStatus",
    "before": "active",
    "after": "liquidation",
    "detectedAt": "2026-07-05T01:24:31.201Z"
}

First run per company emits a baseline-created row; changes flow from the second run. Event types: companyName-changed, companyStatus-changed, companyType-changed, sicCodes-changed, registeredOffice-changed, accountsNextDue-changed, confirmationStatementNextDue-changed, officersActiveCount-changed, new-filing.

Setup (2 minutes)

1. Get a free API key: developer.company-information.service.gov.uk → register an application → REST API key.
2. Paste it into the apiKey input field (stored as an Apify secret).
3. Add your company numbers and create a Schedule (daily 07:00 works well).

No key yet? Run with "mockMode": true to see the change-detection engine work on bundled example fixtures.

Input

{
    "companyNumbers": ["01234567", "SC123456"],
    "apiKey": "YOUR_FREE_CH_KEY",
    "emitSnapshots": false
}

Pricing (pay per event)

Event	Price
Actor start	$0.02 per run
Company checked	$0.005 per company per run
Change detected	$0.01 per change

Watching 100 companies daily costs about $0.52/day plus a penny per actual change — cheaper than one missed insolvency.

Fair use & data sources

Uses the official Companies House REST API under your own free API key, within the published rate limit (600 requests / 5 minutes — the actor self-throttles to stay inside it). Companies House data is Crown copyright public data, free to use including commercially under the Companies House usage terms. No scraping.

Limitations (told straight)

• Officer-level detail: v1 tracks the active-officer count, not per-officer appointments/resignations (that's the natural v2 — tell me if you want it).
• Change detection is per-run: schedule cadence = detection latency. Companies House also offers a streaming API; this actor deliberately uses the simpler REST polling model for reliability.
• PSC (persons with significant control) changes are not yet watched (v2 candidate).