SpamFixer Email Deliverability Check MCP

This MCP server allows AI assistants to check the email deliverability status of any domain by analyzing public DNS records including SPF, DKIM, DMARC, MX, and blocklist status. It provides a plain-English explanation of issues ranked by severity and a deliverability score out of 100. The tool is read-only, requires no authentication, and is free to use.

Visit SpamFixer

Endpoint and access

No sign-in to connect and list tools. Individual tools may still need a vendor account, credentials, or permissions; check the documented prerequisites.

Vendor evidenceStreamable HTTPNo sign-inEndpoint checked 2026-11-01Operated by SpamFixer

MCP endpoint (Streamable HTTP)

https://spamfixer.com/mcp

Vendor documentation

What you can do with it

Why are my emails going to spam?
Is the email for my domain set up correctly?
Do I have DMARC set up on mybakery.com?

Source and maintenance

Vendor evidenceRegistry 1.0.0

mcp-registry: com.spamfixer/email-deliverability-check@1.0.0 Project website

Protocol and capabilities

Server: spamfixer 1.0.0
MCP protocol: 2025-06-18
Tools: 1 advertised
Resources: 0 advertised
Resource templates: 0 advertised
Prompts: 0 advertised

Server-advertised capabilities

{
  "tools": {
    "listChanged": false
  },
  "prompts": {
    "listChanged": false
  },
  "resources": {
    "subscribe": false,
    "listChanged": false
  },
  "experimental": {}
}

Server-provided instructions

Untrusted server output shown for inspection. It is not Koskamo guidance and is excluded from knowledge search.

Use check_email_deliverability when someone asks why their emails go to spam or junk, whether their domain's email is set up correctly, or about SPF, DKIM or DMARC. It only reads public DNS, so it works for any domain without an account.

Tools

1 advertised

check_email_deliverability — Check email deliverability

Advertised by the server during the last successful anonymous check.

Advertised read-onlyOpen-world

Check why emails from a domain might land in spam. Looks up the domain's public DNS: SPF, DKIM (common selectors), DMARC, MX, and whether its mail servers are on major blocklists. Returns a 0-100 score and plain-English issues, worst first. Read-only: it changes nothing and sends no email. DKIM keys on custom selectors can't be found from outside, so "DKIM not found" is only a hint. Free email providers (gmail.com etc.) aren't checked. Args: domain: The domain that sends the email, e.g. "joesplumbing.com". A website URL or an email address also works; the domain is taken from it.

check_email_deliverability input schema

{
  "type": "object",
  "title": "check_email_deliverabilityArguments",
  "required": [
    "domain"
  ],
  "properties": {
    "domain": {
      "type": "string",
      "title": "Domain"
    }
  }
}

check_email_deliverability output schema

{
  "type": "object",
  "title": "check_email_deliverabilityOutput",
  "required": [
    "result"
  ],
  "properties": {
    "result": {
      "type": "string",
      "title": "Result"
    }
  }
}

check_email_deliverability annotations

{
  "readOnlyHint": true,
  "openWorldHint": true,
  "idempotentHint": true,
  "destructiveHint": false
}

Prompts

0 advertised

No prompt definitions available.

Resources

0 advertised

No resource definitions available.

30-day availability

Aggregated from read-only remote checks; this is not a tool-execution or security guarantee.

Successful checks: 1 of 1 (100%)
Average latency: 317 ms
95th percentile latency: 317 ms

Maintenance history

Public check and source-refresh events. Editorial and ownership records remain private.

Nov 1, 2026, 8:50 AM UTC · probe · passed · 317 ms · metadata changed · 1 tool(s), 0 resource(s), 0 resource template(s), 0 prompt(s)

Connect from your client

Each snippet registers the same endpoint; pick the client you use.

This server is operated by the named third party. Listing and endpoint checks are not an endorsement or a security audit. Review the operator's permissions, terms, and data handling before connecting. How listings are checked and corrected.

Claude Code

Run this once in a terminal. It registers the remote server. Use --scope project to write .mcp.json for the repo.

Claude Code configuration

claude mcp add --transport http spamfixer-email-deliverability-check-mcp https://spamfixer.com/mcp

Codex

Run this once. Codex stores MCP servers in ~/.codex/config.toml (or .codex/config.toml in a trusted project).

Codex configuration

codex mcp add spamfixer-email-deliverability-check-mcp --url https://spamfixer.com/mcp

Cursor

Merge this server into .cursor/mcp.json in your project, then enable spamfixer-email-deliverability-check-mcp in your MCP settings.

Cursor configuration

{
  "mcpServers": {
    "spamfixer-email-deliverability-check-mcp": {
      "url": "https://spamfixer.com/mcp"
    }
  }
}

Cline

Merge this into cline_mcp_settings.json (Cline → MCP Servers → Configure).

Cline configuration

{
  "mcpServers": {
    "spamfixer-email-deliverability-check-mcp": {
      "type": "streamableHttp",
      "url": "https://spamfixer.com/mcp",
      "disabled": false
    }
  }
}

VS Code

Merge this server into .vscode/mcp.json. Use MCP: List Servers to start spamfixer-email-deliverability-check-mcp and inspect its tools.

VS Code configuration

{
  "servers": {
    "spamfixer-email-deliverability-check-mcp": {
      "type": "http",
      "url": "https://spamfixer.com/mcp"
    }
  }
}

Gemini CLI

Run this once. It writes .gemini/settings.json in the current project; pass --scope user for ~/.gemini/settings.json.

Gemini CLI configuration

gemini mcp add --transport http spamfixer-email-deliverability-check-mcp https://spamfixer.com/mcp

Claude Desktop

Merge this into claude_desktop_config.json (macOS: ~/Library/Application Support/Claude/, Windows: %APPDATA%\Claude\), then restart Claude Desktop.

Claude Desktop configuration

{
  "mcpServers": {
    "spamfixer-email-deliverability-check-mcp": {
      "url": "https://spamfixer.com/mcp"
    }
  }
}

Windsurf

Merge this into ~/.codeium/windsurf/mcp_config.json, then refresh MCP in Cascade. Windsurf remote servers use serverUrl, not url.

Windsurf configuration

{
  "mcpServers": {
    "spamfixer-email-deliverability-check-mcp": {
      "serverUrl": "https://spamfixer.com/mcp"
    }
  }
}

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