# Moz API vs Similarweb

> Similarweb and Moz API score within a point of each other on agent readiness, 46 (D) and 45.3 (E). Moz API leads on reliability, agent ergonomics and payments & pricing. Both do seo keywords. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/moz-api-vs-similarweb
- Markdown: https://www.anchorterminal.com/compare/moz-api-vs-similarweb.md (~2,000 tokens)
- Slim: https://www.anchorterminal.com/compare/moz-api-vs-similarweb.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/moz-api-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: 2026-10-08

Similarweb and Moz API score within a point of each other on agent readiness, 46 (D) and 45.3 (E). Moz API leads on reliability, agent ergonomics and payments & pricing. Both do seo keywords.

- Moz API: grade E, 45.3/100, rank #571 of 629. Markdown https://www.anchorterminal.com/tools/moz-api.md · JSON https://www.anchorterminal.com/api/v1/tools/moz-api.json
- Similarweb: grade D, 46/100, rank #566 of 629. Markdown https://www.anchorterminal.com/tools/similarweb.md · JSON https://www.anchorterminal.com/api/v1/tools/similarweb.json

## Which one, for what

### Moz API (E)

Good for: Agents that need Domain Authority, backlink lists, link intersects, keyword volume and difficulty, search intent and ranking keywords at a low entry price, on a read-only data set.

Ahead on:
- Reliability, 42 against 35
- Agent ergonomics, 74 against 67
- Payments & pricing, 20 against 5

Watch for: No working public status page was found, and moz.statuspage.io reports the Moz Status page as inactive

### 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:
- Schema & documentation, 63 against 50
- Security & auth, 52 against 38
- Maintenance & community, 33 against 28

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 | Moz API | Similarweb | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 42 | 35 | Moz API +7 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 50 | 63 | Similarweb +13 |
| Agent ergonomics | 13% (16.2 this run) | 74 | 67 | Moz API +7 |
| Security & auth | 14% (17.5 this run) | 38 | 52 | Similarweb +14 |
| Payments & pricing | 10% (12.5 this run) | 20 | 5 | Moz API +15 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 28 | 33 | Similarweb +5 |
| Transparency & trust | 7% (8.8 this run) | 59 | 60 | Similarweb +1 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **45.3 · E** | **46 · D** | |

## Facts side by side

| Fact | Moz API | Similarweb |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | SEOmoz, Inc. | Similarweb Ltd. |
| Hosted endpoint | `https://api.moz.com/jsonrpc` | `https://api.similarweb.com` |
| Transports | HTTP, Streamable HTTP | HTTP |
| Auth | API key | OAuth or key |
| Pricing | Freemium | Paid |
| x402 | no | no |
| Licence | Proprietary service under the Moz API General Conditions (effective 12 August 2026 for new subscribers). Displaying Moz data to others requires attribution under the API legal page | Proprietary service under Similarweb's terms of use |
| Read-only variant documented | no | no |
| llms.txt | no | yes |
| Last release | 2026-08-14 | 2026-09-24 |
| Terms last updated | 2026-08-12 | 2025-03-19 |
| Privacy policy last updated | 2025-04-08 | 2026-06-30 |
| 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 | yes | yes |
| Terms or service can change without notice | yes | not found in the text |
| Arbitration or class-action waiver | yes | not found in the text |

## Verdicts

**Moz API.** The JSON-RPC API documents every error code, its rate limits and the row cost of each method, and failed validation uses no quota. No working status page, SLA, machine-readable spec or official SDK was found. Tokens carry no scopes, and the free plan needs a credit card.

**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

### Moz API

1. Send a request `id` of at least 24 characters (letters, numbers and hyphens). A UUID works. Shorter ids are rejected with -32654.
2. Stop on a 401. Ten 401 or 403 responses in five minutes block the caller for 30 minutes.
3. On 429 with code -32658 wait the `Retry-After` seconds. On code -32650 no wait time is given, so back off exponentially.
4. Call `quota.lookup` (free) before large pulls. List methods charge one row per result, and `limit` is capped at 50 on link lists.
5. Poll `async.call.lookup` for `data.keyword.serp.generate`, and collect the result within 20 seconds of first seeing it complete.

### 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, Moz API or Similarweb?

Similarweb and Moz API score within a point of each other on agent readiness, 46 (D) and 45.3 (E). Moz API leads on reliability, agent ergonomics and payments & pricing.

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

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

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

Yes. Moz API has a hosted endpoint at https://api.moz.com/jsonrpc and Similarweb at https://api.similarweb.com.


## For agents

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

## Other comparisons with Moz API or Similarweb

- [Ahrefs vs Moz API](https://www.anchorterminal.com/compare/ahrefs-vs-moz-api.md)
- [Ahrefs vs Similarweb](https://www.anchorterminal.com/compare/ahrefs-vs-similarweb.md)
- [DataForSEO vs Moz API](https://www.anchorterminal.com/compare/dataforseo-vs-moz-api.md)
- [DataForSEO vs Similarweb](https://www.anchorterminal.com/compare/dataforseo-vs-similarweb.md)
- [Manifold vs Moz API](https://www.anchorterminal.com/compare/manifold-mcp-vs-moz-api.md)
- [Manifold vs Similarweb](https://www.anchorterminal.com/compare/manifold-mcp-vs-similarweb.md)
- [Moz API vs Semrush API + MCP](https://www.anchorterminal.com/compare/moz-api-vs-semrush.md)
- [Semrush API + MCP vs Similarweb](https://www.anchorterminal.com/compare/semrush-vs-similarweb.md)