Companies House Website vs API vs Monitoring Tools — Which is Best?
According to Companies House, 801,864 companies were incorporated in the UK in the year ending March 2025 (Companies House FYE 2025). Professional services firms wanting to identify and reach these new businesses have three main approaches: the free Companies House website, the free API, or specialised monitoring tools.
Each approach involves different trade-offs in cost, effort, and capability, and the right choice depends entirely on what resources you have available and what you actually need the data to do for you.
The Companies House Website
Free, public, and requires no technical skills — but limited for proactive lead generation.
The official Companies House website provides basic search functionality at no cost. It’s free. You can search for companies by name, registration number, or officer details.
What it offers
- Search for individual companies by name or number
- View company details: directors, registered address, SIC codes, filing history
- Download accounts and annual returns
- Set up basic “Follow” alerts for specific companies you already know about
- Free and open to everyone
Link: Companies House search
Limitations for lead generation
The Companies House website is designed for looking up companies you already know about. Discovery is the problem. You cannot browse by geography or search “show me all companies in Glasgow” or filter by postcode. There is no notification system for new incorporations. You cannot export bulk data or download lists of new companies. Browsing by SIC code is not supported either.
For a single company lookup, the website works fine. For systematic lead generation? Impractical.
The Companies House API
Powerful and free, but requires significant technical expertise to implement and maintain.
Companies House provides a free API that allows developers to access company data programmatically, including a real-time streaming feed of company events. The API is well documented and genuinely powerful.
Building a production monitoring system around it, though, requires considerable resources. Development expertise is essential since the API requires specialist knowledge to implement reliably. You need server infrastructure running continuously, either a dedicated server or cloud service. Custom filtering and storage logic must be built to extract only relevant data and store it in a database. And ongoing maintenance is unavoidable, covering connection handling, API updates, and data quality checks.
Most professional services firms don’t have in-house developers, and for those firms, building something custom around the API rarely makes sense when the development cost could fund years of subscription to a ready-made tool.
Who should use the API directly?
The raw API makes sense for:
- Software companies building data products
- Large enterprises with dedicated technical teams
- Researchers analysing company formation patterns
Accounting practices without in-house development resources will find the implementation and maintenance overhead prohibitive.
What the API does NOT provide
- Email addresses or phone numbers
- Revenue or financial performance data
- Alerts or notifications (you must build these yourself)
- Geographic filtering (you must implement postcode matching)
Automated Monitoring Tools
Purpose-built services that handle the technical complexity and deliver structured alerts directly.
A middle ground exists between manual searching and building your own system: services that monitor Companies House and deliver filtered, relevant results directly to your inbox.
What they offer
- Automatic tracking of new company incorporations
- Filtering by postcode area, region, or country
- Industry classification using SIC codes
- Regular email alerts (daily, weekly)
- Structured dashboards for reviewing and managing leads
- No technical skills required
Range of options
The market includes enterprise data providers and specialised monitoring tools:
Enterprise business intelligence platforms
- Comprehensive data services offering company information alongside credit scoring, financial analysis, and risk assessment
- Designed for large organisations and financial institutions, with pricing that reflects enterprise-scale requirements
Specialised monitoring tools
- Focused specifically on new company alerts for professional services firms
- More affordable and purpose-built for lead generation workflows
- Services like Signalyst fall into this category, providing postcode-filtered alerts for Scottish accountants
Side-by-side comparison
| Feature | CH Website | CH API | Monitoring Tools |
|---|---|---|---|
| Cost | Free | Free (+ infrastructure) | £49–£99/month+ |
| Technical skill needed | None | High (developer required) | None |
| Browse by location | No | Build it yourself | Yes |
| Automatic alerts | No | Build it yourself | Yes |
| SIC code filtering | No | Build it yourself | Yes |
| Real-time data | No | Yes (Streaming API) | Depends on provider |
| Maintenance required | None | Ongoing (server, code, monitoring) | None |
| Best for | One-off research | Custom integrations | Professional services firms |
Which approach is right for you?
Choose the website if...
- You want to research a specific known company
- You need to check a company's filing history or directors
- You're doing occasional, manual due diligence
Choose the API if...
- You have a developer on your team
- You want to build a custom integration into your CRM
- You need full control over data processing and storage
The Scottish context
Scotland typically sees 13,000–18,000 new incorporations per year, concentrated in postcode areas including G (Glasgow), EH (Edinburgh), AB (Aberdeen), DD (Dundee), and FK (Falkirk/Stirling).
A practice monitoring just one or two postcode districts might see 20–40 new companies each week. Volume isn’t the point. Even if only a small percentage convert into clients, the pipeline is consistent and the timing advantage over competitors who aren’t monitoring is substantial.
Consistency matters more than volume. A steady pipeline of 10 relevant new companies per week is more valuable than a one-off list of 500.
Making the economics work
For most practices, the calculation comes down to opportunity cost: if your hourly rate exceeds £50, outsourcing company monitoring to a dedicated service makes economic sense. The time you’d spend building and maintaining your own system is better invested in client work. In our experience talking to accountants who’ve tried both approaches, those who attempted DIY API solutions typically abandoned them within six months, citing the maintenance burden as the primary reason.
One new client covers months of subscription cost. That’s the entire business case.