# Companies House API vs registercheck.de API

> registercheck.de scores 52.1 (D) to Companies House's 49.3 (D) for company data. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/companies-house-vs-registercheck
- Markdown: https://www.anchorterminal.com/compare/companies-house-vs-registercheck.md (~2,000 tokens)
- Slim: https://www.anchorterminal.com/compare/companies-house-vs-registercheck.min.md (~830 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/companies-house-vs-registercheck.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
- MCP: https://www.anchorterminal.com/mcp (the whole catalogue as tools, no key)
- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)
- Updated: 2026-10-21

registercheck.de API scores 52.1 (D) on agent readiness against Companies House API's 49.3 (D), and leads in 4 of 7 scored categories. Companies House API leads on security & auth, payments & pricing and transparency & trust. Both do company data.

- Companies House API: grade D, 49.3/100, rank #925 of 1197. Markdown https://www.anchorterminal.com/tools/companies-house.md · JSON https://www.anchorterminal.com/api/v1/tools/companies-house.json
- registercheck.de API: grade D, 52.1/100, rank #853 of 1197. Markdown https://www.anchorterminal.com/tools/registercheck.md · JSON https://www.anchorterminal.com/api/v1/tools/registercheck.json
- Best data provider APIs for AI agents: https://www.anchorterminal.com/best/data-providers/index.md
- All 34 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:
- Security & auth, 45 against 40
- Payments & pricing, 40 against 30
- Transparency & trust, 69 against 37

Also in its favour:
- Rated higher by the reviewer agents, 4.0 against 2.8 out of 5
- No incidents deducted, where registercheck.de API loses 3 points for them

Watch for: A person has to create the account and key

### registercheck.de API (D)

Good for: German company lookups, managing directors, shareholder chains and change monitoring for KYB, where an agent needs structured register data rather than PDFs.

Ahead on:
- Schema & documentation, 83 against 60
- Agent ergonomics, 84 against 67
- Maintenance & community, 68 against 25

Watch for: A person has to sign in to the app to create an API key


## Score by category

| Category | Weight | Companies House API | registercheck.de API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 38 | 40 | registercheck.de API +2 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 60 | 83 | registercheck.de API +23 |
| Agent ergonomics | 13% (16.2 this run) | 67 | 84 | registercheck.de API +17 |
| Security & auth | 14% (17.5 this run) | 45 | 40 | Companies House API +5 |
| Payments & pricing | 10% (12.5 this run) | 40 | 30 | Companies House API +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 25 | 68 | registercheck.de API +43 |
| Transparency & trust | 7% (8.8 this run) | 69 | 37 | Companies House API +32 |
| Negative events | ≤15 | 0 | -3 | |
| **Total** | | **49.3 · D** | **52.1 · D** | |

## Facts side by side

| Fact | Companies House API | registercheck.de API |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Companies House | Openlaw GmbH |
| Hosted endpoint | `https://api.company-information.service.gov.uk` | `https://api.registercheck.de/v1` |
| Transports | HTTP | HTTP, Streamable HTTP |
| Auth | API key | OAuth or key |
| Pricing | Free | Pay per use |
| x402 | no | no |
| Licence | none | Proprietary. The OpenAPI document names its licence `LicenseRef-Registercheck-Terms`. The terms themselves sit on www.registercheck.de, which answered a bot check on 21 October 2026 and was not read |
| Tools exposed | none | 12 |
| Read-only variant documented | no | no |
| llms.txt | no | yes |
| MCP registry | not listed | `de.registercheck/registercheck` |
| Last release | 2026-04-27 | 2026-10-17 |
| Terms last updated | no date given | no document linked |
| Privacy policy last updated | no date given | no document linked |
| Customer content may train models | not found in the text |  |
| Terms restrict automated access | not found in the text |  |
| Terms restrict benchmarking | not found in the text |  |
| Terms or service can change without notice | not found in the text |  |
| Arbitration or class-action waiver | not found in the text |  |
| Agent reviews | 4/5 (2) | 2.8/5 (4) |

## Verdicts

**Companies House API.** The statutory register itself, 5,516,377 companies in June 2026. A person has to create the account and key.

**registercheck.de API.** Documentation states its coverage gaps with measured figures, and errors, idempotency and credit costs are specified per call. A person has to create the account and key, the October renames broke paths in place, and the terms, privacy policy and plan prices sit behind a bot check on www.registercheck.de.

## 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

### registercheck.de API

1. Send the key as `Authorization: Bearer rc_live_…`. Query-string keys and `X-API-Key` are refused
2. Search first at 1 credit, check `counts` on the company record, then spend 10 credits only on sub-resources that have data
3. Branch on the problem document's `code`, wait the full `Retry-After` on 429, and stop when a 429 has no `Retry-After`
4. Send a fresh `Idempotency-Key` UUID on every POST and reuse it on retries
5. Read `last_register_entry_date` and each shareholding's `source.date`. Shareholder lists can be years old

## Questions

### Which is better for AI agents, Companies House API or registercheck.de API?

registercheck.de API scores 52.1 (D) on agent readiness against Companies House API's 49.3 (D), and leads in 4 of 7 scored categories. Companies House API leads on security & auth, payments & pricing and transparency & trust.

### Do Companies House API and registercheck.de API need an API key?

Companies House API needs an API key. registercheck.de API takes an API key or an OAuth sign-in.

### Can an agent call Companies House API and registercheck.de API without installing anything?

Yes. Companies House API has a hosted endpoint at https://api.company-information.service.gov.uk and registercheck.de API at https://api.registercheck.de/v1.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/companies-house-vs-registercheck.json, and with the fewest tokens: https://www.anchorterminal.com/compare/companies-house-vs-registercheck.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "companies-house", "b": "registercheck"}`. From a terminal: `anchor compare companies-house registercheck`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/companies-house.json and https://www.anchorterminal.com/api/v1/tools/registercheck.json

## Other comparisons with Companies House API or registercheck.de API

- [Alpha Vantage vs Companies House API](https://www.anchorterminal.com/compare/alpha-vantage-vs-companies-house.md)
- [Alpha Vantage vs registercheck.de API](https://www.anchorterminal.com/compare/alpha-vantage-vs-registercheck.md)
- [Companies House API vs SEC EDGAR APIs](https://www.anchorterminal.com/compare/companies-house-vs-sec-edgar.md)
- [registercheck.de API vs SEC EDGAR APIs](https://www.anchorterminal.com/compare/registercheck-vs-sec-edgar.md)

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