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Companies House Registry (BYOK) — connector documentation

  • MCP endpoint: https://byok-companieshouse-registry.connectorbay.com/mcp
  • REST API: POST https://byok-companieshouse-registry.connectorbay.com/v1/tools/{tool_name}, described by the OpenAPI 3.1 spec at https://byok-companieshouse-registry.connectorbay.com/openapi.json
  • Transport: Streamable HTTP, stateless, MCP specification 2025-06-18 or later
  • Authentication: your own Companies House Registry Companies House API key, sent in the X-Upstream-Key header of every request (never stored, logged or cached)
  • Health: https://byok-companieshouse-registry.connectorbay.com/health · Tool schemas: https://byok-companieshouse-registry.connectorbay.com/tools.json
  • Publisher: Unify Dynamics LLC · connectorbay.com/byok-companieshouse-registry · agent@connectorbay.com

What Companies House Registry (BYOK) is for

Companies House Registry (BYOK) lets an AI assistant read your own Companies House Registry data through the Companies House Registry API with a key you supply (Companies House API key). Read-only: 10 tools (advanced_company_search, search_companies_alphabetically, search_dissolved_companies, get_registered_office_address, get_company_insolvency, get_company_exemptions, list_uk_establishments, get_company_registers, get_charge_details, get_filing_history_item). The BYOK key travels with each request, is used for that one call only and is never stored, logged or cached; it is only ever sent to api.company-information.service.gov.uk. Unofficial connector by Unify Dynamics LLC: not affiliated with, endorsed by or sponsored by Companies House Registry. Companies House Registry and its logos are trademarks of their owners and are used only to say which service the connector works with.

Ask your assistant things like:

  • "Which active private limited companies incorporated in 2026 have SIC code 62012?"
  • "What companies are listed alphabetically around the name Northwind Traders?"
  • "Find dissolved UK companies named Blue Anchor Trading"
  • "What is the registered office address of company 00000006?"
  • "Is company 00000006 in an insolvency process?"
  • "Does company 00000006 have any PSC register exemptions?"

What it does

  • advanced_company_search: Search UK companies by name fragments, status, type, SIC code, location and incorporation or dissolution dates; returns company number, status, dates, SIC codes and registered office.
  • search_companies_alphabetically: List companies whose names sort next to a name, with company number, status and type; page with the ordered_alpha_key_with_id values.
  • search_dissolved_companies: Search dissolved UK companies by name, as an alphabetical list, best match or previous company name; returns dissolution date and old names.
  • get_registered_office_address: Get the current registered office address of a UK company.
  • get_company_insolvency: Get insolvency cases for a UK company: case type, dates, case number and status.
  • get_company_exemptions: Get the disclosure exemptions recorded for a UK company, such as exemption from keeping a PSC register for listed companies.
  • list_uk_establishments: List the UK establishments registered by an overseas company: company number, name, status and locality.
  • get_company_registers: Get where a company keeps its statutory registers (directors, secretaries, members, PSC): register type and where it was moved to.
  • get_charge_details: Get one registered charge of a UK company: charge code, status, key dates, classification and who is entitled to it.
  • get_filing_history_item: Get one filing of a UK company by transaction id: type, category, date, description and page count.

BYOK key

You bring your own Companies House Registry Companies House API key (https://developer.company-information.service.gov.uk/get-started). Your assistant sends it in the X-Upstream-Key header with each request. ConnectorBay uses it for that one call only: it is never stored, logged or cached, never shown in an answer, and it is only sent to api.company-information.service.gov.uk over https, with no redirects followed. Create a key with the fewest permissions the tools need (read-only if the provider offers it), and revoke it at the provider whenever you like.

Data sources

Live from the Companies House Registry API (api.company-information.service.gov.uk) with a BYOK key; documentation: https://developer-specs.company-information.service.gov.uk/companies-house-public-data-api/reference. Endpoints checked against that documentation on 2026-10-16.

What it is not

Unofficial connector by Unify Dynamics LLC: not affiliated with, endorsed by or sponsored by Companies House Registry. Companies House Registry and its logos are trademarks of their owners and are used only to say which service the connector works with. It is read-only: it never creates, changes, sends or deletes anything in your Companies House Registry account.

Built for: Worldwide. Languages: English.