MailX MCP

Official MCP server for MailX email deliverability tools — SPF, DKIM, DMARC, BIMI validation, domain/IP blacklist checks, SMTP/IMAP connectivity tests, DNS lookups (MX, TXT, CNAME, PTR, full A/AAAA/NS/SOA), and ready-to-deploy record generation for any major email provider.

This package is a thin stdio bridge to the hosted MCP server at https://themailx.com/mcp. All tool logic runs server-side; this is ~50 lines of passthrough glue so clients that want stdio (Claude Desktop, local agents) can use it without hand-wiring a remote URL.

Prefer the remote URL directly? Skip this package — point any streamable-HTTP MCP client straight at https://themailx.com/mcp. See install guide for per-client JSON snippets.

Tools

spf_check, dkim_check, dmarc_check, bimi_check — validate authentication records
blacklist_check — check a domain or IP against popular DNSBLs
smtp_check, imap_check — test mail server connectivity with credentials
smtp_finder, imap_finder — look up server settings by provider name
spf_generate, dmarc_generate — produce copy-pasteable DNS records
mx_lookup, txt_lookup, cname_lookup, ptr_lookup, dns_lookup — DNS queries
bimi_host — host a BIMI SVG for email authentication

Full catalog + live descriptions: themailx.com/mcp/docs

Install

Claude Desktop

Edit ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or the equivalent on your OS:

{
  "mcpServers": {
    "mailx": {
      "command": "npx",
      "args": ["-y", "@mailwarm/mailx-mcp"]
    }
  }
}

Claude Code

claude mcp add mailx -- npx -y @mailwarm/mailx-mcp

Cursor / Windsurf / VS Code / Zed

Same npx -y @mailwarm/mailx-mcp pattern — see your client's MCP config docs for the exact JSON shape. Full examples at themailx.com/mcp/docs.

Direct remote (no install)

If your client supports streamable-HTTP, point it at https://themailx.com/mcp directly — this bridge is only needed for stdio clients.

Configuration

Optional session preferences (set once in your MCP client config, applied to every call):

Variable	Effect
`default_dkim_selector`	Default selector used by `dkim_check` when the call omits `dkim_selector`
`preferred_provider`	Default provider for `spf_generate` (google, mailgun, sendgrid, postmark, amazon-ses, outlook, zoho, fastmail)
`dmarc_aggregate_email`	Default `rua=` address for `dmarc_generate`

Override the upstream URL (staging/self-hosting):

{
  "mcpServers": {
    "mailx": {
      "command": "npx",
      "args": ["-y", "@mailwarm/mailx-mcp"],
      "env": { "MAILX_MCP_URL": "https://tools-stg.themailx.com/mcp" }
    }
  }
}

Prompts

Two one-click slash commands ship with the server:

audit-deliverability(domain) — full deliverability audit (SPF + DMARC + DKIM + blacklist) with copy-pasteable fixes
setup-dns(domain, provider) — greenfield DNS setup, generates SPF + DMARC for the chosen provider

License

MIT — see LICENSE

mailX tools