Getting started

Use SEO data from REST or MCP

One Client API Key gives you access to the supported Semrush SEO API v3 REST surface and a higher-level MCP research layer. Start with a header, not a key in the URL.

REST API

Compatible raw SEO API v3 requests.

https://api.seoapikey.com

MCP

Higher-level tools for research workflows.

https://mcp.seoapikey.com/v2/mcp

Check Balance

View the remaining API Units for a Client Key.

Check API Units

REST API

Keep your SEO API v3 request shape

Use https://api.seoapikey.com as the base URL. Send your Client API Key in the preferred request header:

Authentication header
X-Sem-Pool-Key: YOUR_API_KEY

Header authentication is recommended. Compatibility requests may use ?key=YOUR_API_KEY, but URLs are easier to expose in logs and browser history.

For existing Semrush SEO API v3 code, replace the official API host and key while retaining supported parameters such as type, domain, phrase, database, and display_limit.

Domain Rank

curl
curl -H "X-Sem-Pool-Key: YOUR_API_KEY" \
"https://api.seoapikey.com/?type=domain_rank&domain=example.com&database=us"

Domain Organic

curl
curl -H "X-Sem-Pool-Key: YOUR_API_KEY" \
"https://api.seoapikey.com/?type=domain_organic&domain=example.com&database=us&display_limit=10"

Keyword Organic

curl
curl -H "X-Sem-Pool-Key: YOUR_API_KEY" \
"https://api.seoapikey.com/?type=phrase_organic&phrase=seo&database=us&display_limit=10"
curl
curl -H "X-Sem-Pool-Key: YOUR_API_KEY" \
"https://api.seoapikey.com/analytics/v1/?type=backlinks_overview&target=example.com&target_type=root_domain"

MCP

Connect a research assistant

MCP uses the same Client API Key and the same API Units balance as REST. It is a higher-level research layer over the REST Pool, not a one-tool-per-raw-report mirror.

Endpoint
https://mcp.seoapikey.com/v2/mcp
Authorization
Authorization: Apikey YOUR_API_KEY
MCP JSON configuration
{
  "mcpServers": {
    "seo_api_key": {
      "url": "https://mcp.seoapikey.com/v2/mcp",
      "headers": {
        "Authorization": "Apikey YOUR_API_KEY"
      }
    }
  }
}

Supported MCP categories include domain, keyword, organic, paid search, competitor, backlinks, and shopping research.

Check Balance

Check remaining API Units

The key is sent only in a JSON POST body. It is not placed in the URL, stored, cached, or logged by this documentation flow.

Enter a Client API Key to check its balance.

Supported Features

Supported SEO API v3 surface

61/61 raw SEO API v3 report types have a supported live path.

Domain & keyword

Domain Analytics, Keyword Analytics, Organic Research, and Paid Search / Ads.

Competitive data

Backlinks, Historical Ads, and competitor research.

Specialized reports

Shopping Live Reports, Rank History, and supported daily result views.

Supported display_daily

The accepted value is exactly display_daily=1 for:

  • domain_rank_history
  • subdomain_rank_history
  • subfolder_rank_history
  • url_rank_history
  • domain_organic
  • subdomain_organic
  • subfolder_organic

Requests with blank, duplicate, zero, invalid, or other values are rejected.

Limitations

Deliberately bounded scope

This service does not claim coverage for every Semrush product or parameter combination.

Outside the service scope

  • Semrush API v4
  • Projects
  • Position Tracking
  • Site Audit
  • Audience
  • Traffic / Trends

Current parameter limits

  • Historical Shopping
  • positive Shopping display_offset
  • some additional Organic historical/date variants
  • Shopping display_daily

Unsupported or pricing-ambiguous requests may fail closed before upstream execution.

Security

Treat your Client API Key like a password

Do not publish it, upload it to GitHub, commit it into source code, place it in frontend JavaScript, include it in screenshots, or share it with unrelated users.

Store it safely

Use environment variables, a secret manager, or a password manager.

If it is exposed

Contact the administrator and disable or replace the Client Key.

Control usage

Set a reasonable display_limit and check balance before large jobs.

Each Client Key has its own quota, remaining Units, and expiry. Charges reflect the executed report and actual service accounting.

Official Reference

Report parameters and response fields

Use the official Semrush SEO API v3 reference for report-specific parameters and response fields, then substitute this service's host and authentication method for supported requests.

Open the official Semrush SEO API v3 overview