SecureSMTP MCP server

Connect SecureSMTP to Claude and other MCP clients. Send transactional mail, manage sending domains, and read delivery analytics for your account — in natural language.

• Endpoint: https://securessmtp.com/api/mcp (Streamable HTTP)
• Auth: OAuth 2.1 (one-click, recommended) or a site API key as a Bearer token
• Cost: free — every call runs against your own account and stays within your plan limits

What it can do

Every tool is scoped to a single site, so a connection can only ever see or act on that account.

Connect from Claude Code

OAuth (opens a browser to approve):

claude mcp add --transport http securessmtp https://securessmtp.com/api/mcp

Or with a site API key (no browser step):

claude mcp add --transport http securessmtp https://securessmtp.com/api/mcp \
  --header "Authorization: Bearer <your-site-api-key>"

Connect from claude.ai (custom connector)

Requires a claude.ai Pro/Team/Enterprise plan (custom connectors are not available on the free tier).

1. Settings → Connectors → Add custom connector
2. URL: https://securessmtp.com/api/mcp
3. Approve access when the SecureSMTP consent screen appears, and pick which site to grant.

Where to get an API key

Sign in at securessmtp.com, open a site, and copy its API key — the same key the WordPress plugin and REST API use.

How auth works

• OAuth 2.1 with PKCE and dynamic client registration. Discovery lives at /.well-known/oauth-protected-resource and /.well-known/oauth-authorization-server. Access tokens are short-lived; refresh tokens rotate.
• API key — send the site key as Authorization: Bearer <key>.

Links

• Website: https://securessmtp.com
• API docs: https://securessmtp.com/docs/api
• Support: https://securessmtp.com/contact

Connect from any MCP client

The server is remote (Streamable HTTP). Use OAuth (a browser approval) or send your site API key as a Bearer header. Endpoint: https://securessmtp.com/api/mcp

Claude Code (CLI)

claude mcp add --transport http securessmtp https://securessmtp.com/api/mcp
# with an API key instead of OAuth:
claude mcp add --transport http securessmtp https://securessmtp.com/api/mcp \
  --header "Authorization: Bearer <your-site-api-key>"

Cursor — ~/.cursor/mcp.json (or .cursor/mcp.json in a project)

{
  "mcpServers": {
    "securessmtp": {
      "url": "https://securessmtp.com/api/mcp"
    }
  }
}

With an API key instead of OAuth, add headers:

{
  "mcpServers": {
    "securessmtp": {
      "url": "https://securessmtp.com/api/mcp",
      "headers": { "Authorization": "Bearer <your-site-api-key>" }
    }
  }
}

VS Code (GitHub Copilot) — .vscode/mcp.json

{
  "servers": {
    "securessmtp": {
      "type": "http",
      "url": "https://securessmtp.com/api/mcp"
    }
  }
}

Codex CLI, Claude Desktop, Windsurf, Cline (stdio clients)

Clients that only speak stdio connect through the mcp-remote bridge, which also handles the OAuth browser flow for you.

Codex CLI — ~/.codex/config.toml:

[mcp_servers.securessmtp]
command = "npx"
args = ["-y", "mcp-remote", "https://securessmtp.com/api/mcp"]

Claude Desktop / Windsurf / Cline — the JSON mcpServers block:

{
  "mcpServers": {
    "securessmtp": {
      "command": "npx",
      "args": ["-y", "mcp-remote", "https://securessmtp.com/api/mcp"]
    }
  }
}

Getting an API key

Sign in at securessmtp.com, open a site, and copy its API key. OAuth needs no key — you approve access in the browser and pick which site to grant.