Head to head · Seo keywords · October 2026 research run
Semrush API + MCP vs Similarweb
Semrush API + MCP scores 53.1 (D) on agent readiness against Similarweb's 46 (D), and leads in 6 of 7 scored categories. Both do seo keywords.
Which one, for what
Good for Teams already paying for Semrush who want an agent to pull keyword, backlink, ranking and traffic estimates in one place, mainly through the MCP server.
Ahead on
- Schema & documentation, 70 against 63
- Agent ergonomics, 77 against 67
- Payments & pricing, 17 against 5
- Maintenance & community, 57 against 33
- Transparency & trust, 67 against 60
Watch for
Domain, URL, Trends, Position Tracking and Site Audit reports are version 3 only, where the one key is a URL parameter and can't be revoked
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.
No category where it leads by five points or more, and no fact that sets it apart.
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 this run | Semrush API + MCP | Similarweb | Edge |
|---|---|---|---|---|
| Reliability | 16%20 | 34 | 35 | Similarweb +1 |
| Performance | 10%pending | pending | pending | not scored in this run |
| Schema & documentation | 13%16.2 | 70 | 63 | Semrush API + MCP +7 |
| Agent ergonomics | 13%16.2 | 77 | 67 | Semrush API + MCP +10 |
| Security & auth | 14%17.5 | 54 | 52 | Semrush API + MCP +2 |
| Payments & pricing | 10%12.5 | 17 | 5 | Semrush API + MCP +12 |
| Task success | 10%pending | pending | pending | not scored in this run |
| Maintenance & community | 7%8.8 | 57 | 33 | Semrush API + MCP +24 |
| Transparency & trust | 7%8.8 | 67 | 60 | Semrush API + MCP +7 |
| Negative events | ≤15 | 0 | 0 | |
| Total | 53.1 · D | 46 · D |
Facts side by side
| Fact | Semrush API + MCP | Similarweb |
|---|---|---|
| Kind | HTTP API | HTTP API |
| Vendor | Semrush Inc. (an Adobe company) | Similarweb Ltd. |
| Hosted endpoint | https://api.semrush.com | https://api.similarweb.com |
| Transports | HTTP, Streamable HTTP | HTTP |
| Auth | OAuth or key | OAuth or key |
| Pricing | Paid | Paid |
| x402 | no | no |
| Licence | Proprietary service under the Semrush terms of service | Proprietary service under Similarweb's terms of use |
| Tools exposed | 14 | none |
| Read-only variant documented | yes | no |
| llms.txt | yes | yes |
| Last release | 2026-09-04 | 2026-09-24 |
| Terms last updated | 2026-08-25 | 2025-03-19 |
| Privacy policy last updated | 2025-10-13 | 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 | yes | yes |
| Terms or service can change without notice | not found in the text | not found in the text |
| Arbitration or class-action waiver | yes | not found in the text |
Verdicts
Semrush API + MCP
The hosted MCP server exposes 14 tools that load a report's parameters on demand, and version 4 API keys can be read-only, time-limited and revoked. Most reports still sit in version 3, whose single key travels in the URL and can't be revoked. No status page, OpenAPI file or API unit price was found.
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
Semrush API + MCP
- Use the MCP server at https://mcp.semrush.com/v2/mcp where the host supports it. Call a discovery tool, then
get_report_schema, thenexecute_report - Set
limitordisplay_limiton every per-line report. A backlinks row costs 40 to 45 units and a historical keyword row 50 - Check the unit balance before large pulls. A per-line report returns only the lines the balance covers, with no error
- Send the version 4 key as
Authorization: Apikey <key>, never as?key=. Version 3 accepts only the query parameter, so keep those URLs out of logs - Stay under 10 requests a second and 10 concurrent requests per account, and retry only when
error.retryableis true
Similarweb
- Send the key in the
api-keyheader. The capabilities endpoint documents?api_key=in the URL, which puts the secret in logs - Stay under 10 requests a second. A 429 can also mean the monthly credit allowance is spent, so call
/capabilities(free) before retrying - Pass domains in lower case without
www.or a path. The docs list 401 as data not found for a malformed domain - Request only the metrics, countries and months needed. Credits multiply across domains, metrics, countries and periods, and daily granularity costs about 30 times monthly
- Website keywords accept monthly granularity for the last three months only, and
positionisn't returned for worldwide
Questions
Which is better for AI agents, Semrush API + MCP or Similarweb?
Semrush API + MCP scores 53.1 (D) on agent readiness against Similarweb's 46 (D), and leads in 6 of 7 scored categories.
Do Semrush API + MCP and Similarweb need an API key?
Both take an API key or an OAuth sign-in.
Can an agent call Semrush API + MCP and Similarweb without installing anything?
Yes. Semrush API + MCP has a hosted endpoint at https://api.semrush.com and Similarweb at https://api.similarweb.com.
Other comparisons with Semrush API + MCP or Similarweb
Machine-readable
- This page as Markdown
/compare/semrush-vs-similarweb.md· slim.min.md· JSON.json(or sendAccept: text/markdown) - Each listing in full
/api/v1/tools/semrush.json·/api/v1/tools/similarweb.json - From a terminal
anchor compare semrush similarweb(the CLI) - Over MCP
compare_tools {"a": "semrush", "b": "similarweb"}at/mcp, no key