UK B2B prospecting data sources: what each one is for

Prospecting data comes in layers. Company identity and filings. Company enrichment such as technology, funding and news. People and contact details. Each layer has a different best source in the UK, and the trick is connecting them: a company number from one tool becomes a domain for the next and a decision maker in the third.

Companies House is the register for England, Wales, Scotland and Northern Ireland. Free to search, free API with a key, and the advanced search lets you filter by SIC code, incorporation date, location and status. Use it to build the universe of companies that could fit your profile and to watch for changes. Its limits: SIC codes are self-declared and often loose, small companies file abbreviated accounts, and there is a lag between an event and its filing.

The Gazette carries the official notices Companies House does not: insolvency, administration, winding up, and some corporate actions. It has an open data feed. Charity Commission and the FCA register cover organisations that are not companies or that need authorisation, which matters if you sell to charities or financial firms.

• BuiltWith and Wappalyzer: the technology behind a website. Essential when your fit signal is a platform, a payment provider or a CRM.
• Beauhurst: UK companies that have raised money, won grants, joined accelerators or hit growth triggers. The best single source for funded UK businesses.
• Crunchbase: funding globally, thinner on UK small businesses than Beauhurst.
• Contracts Finder and Find a Tender: free public sector opportunity and award notices, both with open APIs. Council planning portals cover premises but are fragmented, so automating them means an aggregator such as Barbour ABI or Glenigan, or watching the few councils on your patch.
• EPC Open Data and the VOA rating list: free, and the best public proxies for the size and energy performance of a commercial property.
• UK IPO trade mark data: free bulk downloads, and a new filing usually means a product or brand launch months before the announcement.
• Trade press and Google Alerts: unstructured but often the earliest signal.

Credit data is treated as a finance function tool and it is really a prospecting tool. CoCredo, Creditsafe, Red Flag Alert and Company Watch all publish an API, and all of them will monitor a list of companies and tell you when a score moves. A rising score says a company can now afford you. A falling one, a county court judgment or a new charge says something changed this month, which is exactly the timing signal most outreach lacks.

Alongside it sit the free public notices. The Gazette carries insolvency and administration. Contracts Finder and Find a Tender carry public contract awards, both with free APIs in an open standard. Council planning portals carry every application for a new unit, an extension or a change of use. None of these are secret and almost nobody watches them, which is precisely why they still work.

• Apollo.io: a large contact and company database with an API and, increasingly, assistant connectors. Good for finding decision makers by title once you know the company. Coverage of UK small businesses is uneven.
• Cognism: UK and European contact data with a compliance emphasis and phone-verified numbers. Sales-led pricing.
• LinkedIn Sales Navigator: the best view of who does what and who just moved. No public API, so it is a manual research step or a browser workflow. Treat exports with care under its terms.
• Company websites: team pages, case studies and news pages, still the most accurate for small firms.

The question to ask of every tool is whether it has an API or an MCP server. An API lets a platform fetch data on a schedule. An MCP server lets an AI assistant such as Claude call the tool directly in a conversation. Companies House has an API. Apollo has an API and connectors. BuiltWith has an API. Sales Navigator has neither. Public notices sometimes offer feeds and sometimes need scraping. A realistic pipeline mixes all three, and a good plan marks each step as automatic, partial or manual so nobody is surprised.

Stage three of Sales Architect Studio researches the tools that cover your sectors and geography, tells you what each is for and whether it has an API or MCP server, and draws the connections between them. The build blueprint turns that into a pipeline specification you can hand to Claude or to a developer.

How stage three works Automate it with Claude and MCP