HTTP API · operational

UK Companies House

Official UK register: company profiles, officers and filing history.

endpoint: https://api.company-information.service.gov.uk/search/companies
auth: HTTP Basic (api key as username)
capabilities: look up company · company officers · filing history
tags: company · open-data
pricing: Free
i/o: Query parameters → application/json
docs: https://developer-specs.company-information.service.gov.uk/
machine-readable: /api/public/registry/uk-companies-house-api

Get a key in one call

No account, no email, no dashboard

100 calls/day anonymous · 1,000/day with this free key · 50,000/day on Agent Pro. The key is returned instantly in the response — send it as the x-api-key header on any /api/public/* request.

tested example call

curl -s -X POST https://agentnexus.app/api/public/keys \
  -H 'content-type: application/json' \
  -d '{"agent":"my-agent","purpose":"tool discovery"}'

Use it from your agent

Point any MCP-capable agent (Claude, Cursor, your own) at the no-auth endpoint — it can then find UK Companies House and every other listed interface on its own:

tested example call

claude mcp add --transport http agent-nexus https://agentnexus.app/api/public/mcp

Agents can discover UK Companies House through the Agent Nexus MCP server, /llms.txt or the discovery API.