# Majestic API vs Similarweb

> Similarweb scores 46 (D) to Majestic's 33.4 (F) for keyword data. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/majestic-vs-similarweb
- Markdown: https://www.anchorterminal.com/compare/majestic-vs-similarweb.md (~2,350 tokens)
- Slim: https://www.anchorterminal.com/compare/majestic-vs-similarweb.min.md (~630 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/majestic-vs-similarweb.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

Similarweb scores 46 (D) on agent readiness against Majestic API's 33.4 (F), and leads in 6 of 7 scored categories. Majestic API leads on payments & pricing. Both do keyword data.

- Majestic API: grade F, 33.4/100, rank #937 of 950. Markdown https://www.anchorterminal.com/tools/majestic.md · JSON https://www.anchorterminal.com/api/v1/tools/majestic.json
- Similarweb: grade D, 46/100, rank #858 of 950. Markdown https://www.anchorterminal.com/tools/similarweb.md · JSON https://www.anchorterminal.com/api/v1/tools/similarweb.json
- Best SEO and search visibility data for AI agents: https://www.anchorterminal.com/best/seo/index.md
- All 45 seo comparisons: https://www.anchorterminal.com/compare/seo/index.md

## Which one, for what

### Majestic API (F)

Good for: An agent that needs backlink, referring domain, anchor text and Trust Flow data in volume for an owner who already pays for the API plan.

Ahead on:
- Payments & pricing, 15 against 5

Watch for: Clause 14.1(f) of the supply terms forbids querying Majestic's database or servers with automated tools without prior permission. This matters before any probe is run

### Similarweb (D)

Good for: Traffic and engagement estimates, traffic channel mix and keyword click data for domains an agent doesn't own, with app, company and retail data on the same key.

Ahead on:
- Reliability, 35 against 17
- Schema & documentation, 63 against 44
- Agent ergonomics, 67 against 54
- Security & auth, 52 against 32
- Maintenance & community, 33 against 22
- Transparency & trust, 60 against 53

Watch for: API and MCP access need a Business, Enterprise or API-only plan bought through sales. The FAQ says there's no API test without a subscription


## Score by category

| Category | Weight | Majestic API | Similarweb | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 17 | 35 | Similarweb +18 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 44 | 63 | Similarweb +19 |
| Agent ergonomics | 13% (16.2 this run) | 54 | 67 | Similarweb +13 |
| Security & auth | 14% (17.5 this run) | 32 | 52 | Similarweb +20 |
| Payments & pricing | 10% (12.5 this run) | 15 | 5 | Majestic API +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 22 | 33 | Similarweb +11 |
| Transparency & trust | 7% (8.8 this run) | 53 | 60 | Similarweb +7 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **33.4 · F** | **46 · D** | |

## Facts side by side

| Fact | Majestic API | Similarweb |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Majestic (Majestic-12 Limited) | Similarweb Ltd. |
| Hosted endpoint | `https://api.majestic.com` | `https://api.similarweb.com` |
| Transports | HTTP | HTTP |
| Auth | API key | OAuth or key |
| Pricing | Paid | Paid |
| x402 | no | no |
| Licence | Proprietary service under Majestic's Terms and Conditions. The Python 3 connector on GitHub carries a BSD-style licence file | Proprietary service under Similarweb's terms of use |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | none | 2026-09-24 |
| Terms last updated | no date given | 2025-03-19 |
| Privacy policy last updated | 2026-04-01 | 2026-06-30 |
| Customer content may train models | not found in the text | not found in the text |
| Terms restrict automated access | yes | yes |
| Terms restrict benchmarking | not found in the text | yes |
| Terms or service can change without notice | yes | not found in the text |
| Arbitration or class-action waiver | not found in the text | not found in the text |
| Popularity | 3 stars | none |

## Verdicts

**Majestic API.** Each command's cost in units is published and a sandbox endpoint returns sample data without spending allowance. API access starts at $399.99 a month with no trial, and no OpenAPI file, status page, numeric rate limit, SLA or API changelog was found. The supply terms require permission before querying with automated tools.

**Similarweb.** The V5 API returns traffic estimates, keyword clicks and SERP positions with selectable metrics, and the hosted MCP server accepts OAuth with a read scope. Access needs a Business, Enterprise or API-only subscription sold through sales, with no API trial, public price per credit or public status page found.

## Before you call either

### Majestic API

1. Send requests by HTTPS POST with `app_api_key` in the body. The docs show GET URLs for demonstration only and plain HTTP still works
2. Always set `datasource=fresh` or `datasource=historic`. Without it the Historic Index is used when the plan includes it
3. Call `GetSubscriptionInfo` (no cost) before a large pull. `GetBackLinkData` spends 5,000 analysis units a call plus one retrieval unit a row
4. Read columns by header name, not position. The docs say column order can change between requests and Majestic may vary rows and columns at any time
5. Develop against `https://developer.majestic.com/api/json`, which costs no units, then switch the host to `api.majestic.com`
6. Ask the owner to confirm Majestic's permission for automated querying first. Clause 14.1(f) of the terms requires it

### Similarweb

1. Send the key in the `api-key` header. The capabilities endpoint documents `?api_key=` in the URL, which puts the secret in logs
2. Stay under 10 requests a second. A 429 can also mean the monthly credit allowance is spent, so call `/capabilities` (free) before retrying
3. Pass domains in lower case without `www.` or a path. The docs list 401 as data not found for a malformed domain
4. Request only the metrics, countries and months needed. Credits multiply across domains, metrics, countries and periods, and daily granularity costs about 30 times monthly
5. Website keywords accept monthly granularity for the last three months only, and `position` isn't returned for worldwide

## Questions

### Which is better for AI agents, Majestic API or Similarweb?

Similarweb scores 46 (D) on agent readiness against Majestic API's 33.4 (F), and leads in 6 of 7 scored categories. Majestic API leads on payments & pricing.

### Do Majestic API and Similarweb need an API key?

Majestic API needs an API key. Similarweb takes an API key or an OAuth sign-in.

### Can an agent call Majestic API and Similarweb without installing anything?

Yes. Majestic API has a hosted endpoint at https://api.majestic.com and Similarweb at https://api.similarweb.com.


## For agents

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

## Other comparisons with Majestic API or Similarweb

- [Ahrefs vs Majestic API](https://www.anchorterminal.com/compare/ahrefs-vs-majestic.md)
- [Ahrefs vs Similarweb](https://www.anchorterminal.com/compare/ahrefs-vs-similarweb.md)
- [DataForSEO vs Majestic API](https://www.anchorterminal.com/compare/dataforseo-vs-majestic.md)
- [DataForSEO vs Similarweb](https://www.anchorterminal.com/compare/dataforseo-vs-similarweb.md)
- [Google Search Console API vs Majestic API](https://www.anchorterminal.com/compare/google-search-console-vs-majestic.md)
- [Keywords Everywhere API + MCP vs Majestic API](https://www.anchorterminal.com/compare/keywords-everywhere-vs-majestic.md)
- [Keywords Everywhere API + MCP vs Similarweb](https://www.anchorterminal.com/compare/keywords-everywhere-vs-similarweb.md)
- [Manifold vs Similarweb](https://www.anchorterminal.com/compare/manifold-mcp-vs-similarweb.md)
- [Moz API vs Similarweb](https://www.anchorterminal.com/compare/moz-api-vs-similarweb.md)
- [SE Ranking API + MCP vs Similarweb](https://www.anchorterminal.com/compare/se-ranking-vs-similarweb.md)
- [Semrush API + MCP vs Similarweb](https://www.anchorterminal.com/compare/semrush-vs-similarweb.md)
- [Google Search Console API vs Similarweb](https://www.anchorterminal.com/compare/google-search-console-vs-similarweb.md)
- [Majestic API vs Manifold](https://www.anchorterminal.com/compare/majestic-vs-manifold-mcp.md)
- [Majestic API vs Moz API](https://www.anchorterminal.com/compare/majestic-vs-moz-api.md)
- [Majestic API vs SE Ranking API + MCP](https://www.anchorterminal.com/compare/majestic-vs-se-ranking.md)
- [Majestic API vs Semrush API + MCP](https://www.anchorterminal.com/compare/majestic-vs-semrush.md)