UK Companies House Public Data API

Use in your agent

Search Companies House data into pandas and Parquet. Checked against the provider's documentation on Nov 2, 2026.

Access

• Create a Companies House account, application and API key.
• Set COMPANIES_HOUSE_API_KEY in the environment; public GET requests use the key as the Basic Auth username with an empty password.

Request

curl --user "$COMPANIES_HOUSE_API_KEY:" --get --data-urlencode 'q=energy' --data-urlencode 'items_per_page=20' 'https://api.company-information.service.gov.uk/search/companies'

Format

JSON search results with company number, title, status, type, creation or cessation dates, address, SIC-related description snippets and pagination metadata.

Load into pandas and Parquet

Needs Python 3 with requests, pandas and pyarrow.

"""Companies House company search -> pandas -> Parquet."""
import os
import requests
import pandas as pd

URL = "https://api.company-information.service.gov.uk/search/companies"
key = os.environ["COMPANIES_HOUSE_API_KEY"]
response = requests.get(
    URL,
    params={"q": "energy", "items_per_page": 20},
    auth=(key, ""),
    timeout=60,
)
response.raise_for_status()
payload = response.json()
df = pd.json_normalize(payload["items"], sep="_")
for column in ["date_of_creation", "date_of_cessation"]:
    if column in df.columns:
        df[column] = pd.to_datetime(df[column], errors="coerce")
df.to_parquet("companies_house_energy_search.parquet", index=False)
print(len(df), "companies of", payload["total_results"], "matches")

Not run: it needs a free API key.

Limits

• Rate limit: 600 requests per 5 minutes.
• Search endpoints paginate with items_per_page and start_index.
• Searchable databases are not intended for bulk downloads; Companies House provides separate bulk data products.

Quirks

• Company names are not stable identifiers; use company_number for joins and refresh records as filings change.
• Different resources expose different date fields and enumerated codes; retain the raw status and type values alongside normalized labels.
• The provider says the public information is not comprehensive and can contain inaccuracies or later corrections.
• Officer and control resources contain public-register personal information and require lawful downstream handling.

Terms and attribution

• OGL v3 requires source acknowledgement and does not cover personal data, logos or third-party rights.
• Do not imply Companies House endorsement, and do not use automated access in a way that degrades the service.

Sources

• https://developer.company-information.service.gov.uk/: “The data returned is live and real-time, and is simple to use and understand.”
• https://developer.company-information.service.gov.uk/developer-guidelines: “You can make up to 600 requests within a 5 minute period.”
• https://www.gov.uk/guidance/search-the-companies-house-register: “This allows both consumers and technology providers access to real time updates on companies.”
• https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/: “Contains public sector information licensed under the Open Government Licence v3.0.”