Head to head · Company data · October 2026 research run
Companies House API vs 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. Both do company data.
Best data provider APIs for AI agents · All 31 data comparisons
Which one, for what
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
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 this run | Companies House API | SEC EDGAR APIs | Edge |
|---|---|---|---|---|
| Reliability | 16%20 | 38 | 38 | even |
| Performance | 10%pending | pending | pending | not scored in this run |
| Schema & documentation | 13%16.2 | 60 | 23 | Companies House API +37 |
| Agent ergonomics | 13%16.2 | 67 | 41 | Companies House API +26 |
| Security & auth | 14%17.5 | 45 | 52 | SEC EDGAR APIs +7 |
| Payments & pricing | 10%12.5 | 40 | 60 | SEC EDGAR APIs +20 |
| Task success | 10%pending | pending | pending | not scored in this run |
| Maintenance & community | 7%8.8 | 25 | 14 | Companies House API +11 |
| Transparency & trust | 7%8.8 | 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
- Send the key as the Basic auth username with an empty password.
curl -u KEY:works - Search with
/search/companies?q=and page withitems_per_pageandstart_index, then fetch/company/{number} - Pad company numbers to 8 characters with leading zeros
- Stop on the first 429 and wait out the five-minute window, since every call until it resets also fails
- Map filing and error codes to text with the public api-enumerations YAML rather than guessing
SEC EDGAR APIs
- 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
- 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
- Pad the CIK to 10 digits with leading zeros in
submissions/CIK##########.jsonand the XBRL paths. Find a CIK inhttps://www.sec.gov/files/company_tickers.json - Prefer
api/xbrl/companyconcept/for one figure.companyfactsreturns every concept a company has reported, andsubmissionsreturns at least 1,000 filings in column arrays - 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.
Other comparisons with Companies House API or SEC EDGAR APIs
Machine-readable
- This page as Markdown
/compare/companies-house-vs-sec-edgar.md· slim.min.md· JSON.json(or sendAccept: text/markdown) - Each listing in full
/api/v1/tools/companies-house.json·/api/v1/tools/sec-edgar.json - From a terminal
anchor compare companies-house sec-edgar(the CLI) - Over MCP
compare_tools {"a": "companies-house", "b": "sec-edgar"}at/mcp, no key