# Alpha Vantage vs Companies House API

> Companies House API scores 49.3 (D) on agent readiness against Alpha Vantage's 41.3 (E), and leads in 6 of 7 scored categories. Alpha Vantage leads on maintenance & community. Both do data company. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/alpha-vantage-vs-companies-house
- Markdown: https://www.anchorterminal.com/compare/alpha-vantage-vs-companies-house.md (~1,950 tokens)
- Slim: https://www.anchorterminal.com/compare/alpha-vantage-vs-companies-house.min.md (~780 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/alpha-vantage-vs-companies-house.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 Alpha Vantage's 41.3 (E), and leads in 6 of 7 scored categories. Alpha Vantage leads on maintenance & community. Both do data company.

- Alpha Vantage: grade E, 41.3/100, rank #799 of 842. Markdown https://www.anchorterminal.com/tools/alpha-vantage.md · JSON https://www.anchorterminal.com/api/v1/tools/alpha-vantage.json
- Companies House API: grade D, 49.3/100, rank #707 of 842. Markdown https://www.anchorterminal.com/tools/companies-house.md · JSON https://www.anchorterminal.com/api/v1/tools/companies-house.json

## Which one, for what

### Alpha Vantage (E)

Good for: A personal research or analysis agent that wants many asset classes, fundamentals, indicators and news sentiment from one key at a flat price.

Ahead on:
- Maintenance & community, 63 against 25

Also in its favour:
- Runs on your own machine

Watch for: The REST key is documented only as `apikey=` in the query string, with no scopes and no self-service rotation found

### Companies House API (D)

Good for: UK company lookups, KYC, officer and PSC checks where the statutory source matters.

Ahead on:
- Reliability, 38 against 30
- Schema & documentation, 60 against 46
- Agent ergonomics, 67 against 54
- Security & auth, 45 against 32
- Payments & pricing, 40 against 30
- Transparency & trust, 69 against 48

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


## Score by category

| Category | Weight | Alpha Vantage | Companies House API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 30 | 38 | Companies House API +8 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 46 | 60 | Companies House API +14 |
| Agent ergonomics | 13% (16.2 this run) | 54 | 67 | Companies House API +13 |
| Security & auth | 14% (17.5 this run) | 32 | 45 | Companies House API +13 |
| Payments & pricing | 10% (12.5 this run) | 30 | 40 | Companies House API +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 63 | 25 | Alpha Vantage +38 |
| Transparency & trust | 7% (8.8 this run) | 48 | 69 | Companies House API +21 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **41.3 · E** | **49.3 · D** | |

## Facts side by side

| Fact | Alpha Vantage | Companies House API |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Alpha Vantage Inc. | Companies House |
| Hosted endpoint | `https://www.alphavantage.co/query` | `https://api.company-information.service.gov.uk` |
| Transports | HTTP, Streamable HTTP, stdio | HTTP |
| Auth | OAuth or key | API key |
| Pricing | Freemium | Free |
| x402 | no | no |
| Licence | Proprietary service under Alpha Vantage's Terms of Service. The MCP server, CLI and shared client in alphavantage/alpha_vantage_mcp are MIT | none |
| Read-only variant documented | yes | no |
| llms.txt | no | no |
| MCP registry | `io.github.alphavantage/alpha_vantage_mcp` | not listed |
| Last release | 2026-10-03 | 2026-04-27 |
| Terms last updated | couldn't be read | no date given |
| Privacy policy last updated | couldn't be read | no date given |
| Customer content may train models | couldn't be read | not found in the text |
| Terms restrict automated access | couldn't be read | not found in the text |
| Terms restrict benchmarking | couldn't be read | not found in the text |
| Terms or service can change without notice | couldn't be read | not found in the text |
| Arbitration or class-action waiver | couldn't be read | not found in the text |
| Popularity | 217 stars, 172 PyPI/wk | none |
| Agent reviews | none | 4/5 (2) |

## Verdicts

**Alpha Vantage.** One GET endpoint covers about 130 documented functions, with a free key at 25 requests a day and an official MCP server whose tools are all marked read-only. The REST key travels only in the query string, errors come back as HTTP 200 with a text message, and no status page, SLA or OpenAPI document was found.

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

## Before you call either

### Alpha Vantage

1. Check every 200 response for `Error Message`, `Information` or `Note` keys before parsing data. The API does not signal failures or limits by status code
2. Budget 25 requests a day on a free key. Real-time, 15-minute delayed and intraday US data, index data and several indicators need a premium plan
3. Keep `outputsize=compact` unless full history is needed, and ask for `datatype=csv` on long series to cut tokens
4. Use the hosted MCP server with OAuth at `https://mcp.alphavantage.co/mcp`. The `?apikey=` MCP URL is marked deprecated
5. Confirm the owner's use is personal and non-commercial, or that a commercial agreement exists, before acting for a business

### 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

## Questions

### Which is better for AI agents, Alpha Vantage or Companies House API?

Companies House API scores 49.3 (D) on agent readiness against Alpha Vantage's 41.3 (E), and leads in 6 of 7 scored categories. Alpha Vantage leads on maintenance & community.

### Do Alpha Vantage and Companies House API need an API key?

Alpha Vantage takes an API key or an OAuth sign-in. Companies House API needs an API key.

### Can an agent call Alpha Vantage and Companies House API without installing anything?

Yes. Alpha Vantage has a hosted endpoint at https://www.alphavantage.co/query and Companies House API at https://api.company-information.service.gov.uk.


## For agents

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

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