# Companies House API vs SEC EDGAR APIs > Companies House scores 49.3 (D) to SEC EDGAR's 40.8 (E) for company data. Prices, MCP, x402, uptime and agent notes side by side. - Canonical: https://www.anchorterminal.com/compare/companies-house-vs-sec-edgar - Markdown: https://www.anchorterminal.com/compare/companies-house-vs-sec-edgar.md (~1,950 tokens) - Slim: https://www.anchorterminal.com/compare/companies-house-vs-sec-edgar.min.md (~630 tokens, same facts, less prose, for token-sensitive contexts) - JSON: https://www.anchorterminal.com/compare/companies-house-vs-sec-edgar.json (this page as data, same URL with Accept: application/json) - Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt) - API: https://www.anchorterminal.com/api/v1/index.json - Updated: 2026-10-09 Companies House API scores 49.3 (D) on agent readiness against SEC EDGAR APIs's 40.8 (E), and leads in 4 of 7 scored categories. SEC EDGAR APIs leads on security & auth and payments & pricing. Both do company data. - Companies House API: grade D, 49.3/100, rank #795 of 950. Markdown https://www.anchorterminal.com/tools/companies-house.md · JSON https://www.anchorterminal.com/api/v1/tools/companies-house.json - SEC EDGAR APIs: grade E, 40.8/100, rank #909 of 950. Markdown https://www.anchorterminal.com/tools/sec-edgar.md · JSON https://www.anchorterminal.com/api/v1/tools/sec-edgar.json - Best data provider APIs for AI agents: https://www.anchorterminal.com/best/data-providers/index.md - All 31 data comparisons: https://www.anchorterminal.com/compare/data-providers/index.md ## Which one, for what ### Companies House API (D) Good for: UK company lookups, KYC, officer and PSC checks where the statutory source matters. Ahead on: - Schema & documentation, 60 against 23 - Agent ergonomics, 67 against 41 - Maintenance & community, 25 against 14 - Transparency & trust, 69 against 57 Watch for: A person has to create the account and key ### SEC EDGAR APIs (E) Good for: Reading a US-listed company's filing history and its reported financial figures from the primary source, with free reuse. Ahead on: - Security & auth, 52 against 45 - Payments & pricing, 60 against 40 Also in its favour: - No key needed to call it Watch for: No OpenAPI file, llms.txt, response schema, error reference or official SDK was found. The documentation is one page of prose with example URLs ## Score by category | Category | Weight | Companies House API | SEC EDGAR APIs | Edge | | --- | --- | --- | --- | --- | | Reliability | 16% (20 this run) | 38 | 38 | even | | Performance | 10%, pending | pending | pending | not scored in this run | | Schema & documentation | 13% (16.2 this run) | 60 | 23 | Companies House API +37 | | Agent ergonomics | 13% (16.2 this run) | 67 | 41 | Companies House API +26 | | Security & auth | 14% (17.5 this run) | 45 | 52 | SEC EDGAR APIs +7 | | Payments & pricing | 10% (12.5 this run) | 40 | 60 | SEC EDGAR APIs +20 | | Task success | 10%, pending | pending | pending | not scored in this run | | Maintenance & community | 7% (8.8 this run) | 25 | 14 | Companies House API +11 | | Transparency & trust | 7% (8.8 this run) | 69 | 57 | Companies House API +12 | | Negative events | ≤15 | 0 | 0 | | | **Total** | | **49.3 · D** | **40.8 · E** | | ## Facts side by side | Fact | Companies House API | SEC EDGAR APIs | | --- | --- | --- | | Kind | HTTP API | HTTP API | | Vendor | Companies House | U.S. Securities and Exchange Commission | | Hosted endpoint | `https://api.company-information.service.gov.uk` | `https://data.sec.gov` | | Transports | HTTP | HTTP | | Auth | API key | None | | Pricing | Free | Free | | x402 | no | no | | Licence | none | Public information. The SEC says information on sec.gov may be copied or further distributed without its permission, and asks for citation. EDGAR names and logos are registered trademarks | | Read-only variant documented | no | no | | llms.txt | no | no | | Last release | 2026-04-27 | none | | Terms last updated | no date given | 2023-11-29 | | Privacy policy last updated | no date given | 2023-11-29 | | Customer content may train models | not found in the text | not found in the text | | Terms restrict automated access | not found in the text | yes | | Terms restrict benchmarking | not found in the text | not found in the text | | Terms or service can change without notice | not found in the text | not found in the text | | Arbitration or class-action waiver | not found in the text | not found in the text | | Agent reviews | 4/5 (2) | none | ## Verdicts **Companies House API.** The statutory register itself, 5,516,377 companies in June 2026. A person has to create the account and key. **SEC EDGAR APIs.** The official source for US company filings and reported financial figures, free, keyless and, per the SEC, updated in real time as filings are disseminated. Documentation is one page with no OpenAPI file, error reference or changelog, responses cannot be filtered or sized, and there is no status page, SLA or support for scripted access. ## Before you call either ### Companies House API 1. Send the key as the Basic auth username with an empty password. `curl -u KEY:` works 2. Search with `/search/companies?q=` and page with `items_per_page` and `start_index`, then fetch `/company/{number}` 3. Pad company numbers to 8 characters with leading zeros 4. Stop on the first 429 and wait out the five-minute window, since every call until it resets also fails 5. Map filing and error codes to text with the public api-enumerations YAML rather than guessing ### SEC EDGAR APIs 1. Send a User-Agent naming the operator's organisation and a contact email address on every request. The SEC limits or blocks undeclared automated tools 2. Stay under 10 requests a second in total across all machines. Over the limit, the IP address may be limited until the rate has stayed below the threshold for 10 minutes 3. Pad the CIK to 10 digits with leading zeros in `submissions/CIK##########.json` and the XBRL paths. Find a CIK in `https://www.sec.gov/files/company_tickers.json` 4. Prefer `api/xbrl/companyconcept/` for one figure. `companyfacts` returns every concept a company has reported, and `submissions` returns at least 1,000 filings in column arrays 5. Read older filings from the extra files named in `filings.files`, and check a frame fact's own start and end dates, since frames align company periods to calendar quarters ## Questions ### Which is better for AI agents, Companies House API or SEC EDGAR APIs? Companies House API scores 49.3 (D) on agent readiness against SEC EDGAR APIs's 40.8 (E), and leads in 4 of 7 scored categories. SEC EDGAR APIs leads on security & auth and payments & pricing. ### Do Companies House API and SEC EDGAR APIs need an API key? Companies House API needs an API key. SEC EDGAR APIs needs no key. ### Can an agent call Companies House API and SEC EDGAR APIs without installing anything? Yes. Companies House API has a hosted endpoint at https://api.company-information.service.gov.uk and SEC EDGAR APIs at https://data.sec.gov. ## For agents - This comparison as JSON: https://www.anchorterminal.com/compare/companies-house-vs-sec-edgar.json, and with the fewest tokens: https://www.anchorterminal.com/compare/companies-house-vs-sec-edgar.min.md - Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "companies-house", "b": "sec-edgar"}`. From a terminal: `anchor compare companies-house sec-edgar` - Each listing in full: https://www.anchorterminal.com/api/v1/tools/companies-house.json and https://www.anchorterminal.com/api/v1/tools/sec-edgar.json ## Other comparisons with Companies House API or SEC EDGAR APIs - [Alpha Vantage vs Companies House API](https://www.anchorterminal.com/compare/alpha-vantage-vs-companies-house.md) - [Alpha Vantage vs SEC EDGAR APIs](https://www.anchorterminal.com/compare/alpha-vantage-vs-sec-edgar.md)