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Atomic Mail

Atomic Mail is an MCP server that adds messaging tools to AI assistants such as Claude Desktop, Claude Code and Cursor. Programmable email inbox for AI agents — JMAP, PoW auth, stdio MCP server. It has 266 GitHub stars, is released under the MIT license and runs locally with npx -y @atomicmail/mcp-modelcontextprotocol.

github.com/Atomic-Mail/atomic-mail-agentic (opens in a new tab)

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Install Atomic Mail

Generated from the server's MCP registry entry. Replace your-value with your own values.

Claude Desktop

claude_desktop_config.json
{
  "mcpServers": {
    "atomic-mail": {
      "command": "npx",
      "args": [
        "-y",
        "@atomicmail/mcp-modelcontextprotocol"
      ],
      "env": {
        "ATOMIC_MAIL_CREDENTIALS_DIR": "your-value",
        "ATOMIC_MAIL_API_KEY": "your-value",
        "ATOMIC_MAIL_AUTH_URL": "your-value"
      }
    }
  }
}

Settings > Developer > Edit Config. macOS: ~/Library/Application Support/Claude/, Windows: %APPDATA%\Claude\. Restart Claude Desktop afterwards.

Claude Code

claude mcp add --env ATOMIC_MAIL_CREDENTIALS_DIR=your-value --env ATOMIC_MAIL_API_KEY=your-value --env ATOMIC_MAIL_AUTH_URL=your-value --transport stdio atomic-mail -- npx -y @atomicmail/mcp-modelcontextprotocol

Cursor

.cursor/mcp.json
{
  "mcpServers": {
    "atomic-mail": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "@atomicmail/mcp-modelcontextprotocol"
      ],
      "env": {
        "ATOMIC_MAIL_CREDENTIALS_DIR": "your-value",
        "ATOMIC_MAIL_API_KEY": "your-value",
        "ATOMIC_MAIL_AUTH_URL": "your-value"
      }
    }
  }
}

Project file; use ~/.cursor/mcp.json to enable it in every project.

VS Code

.vscode/mcp.json
{
  "inputs": [
    {
      "type": "promptString",
      "id": "atomic_mail_credentials_dir",
      "description": "ATOMIC_MAIL_CREDENTIALS_DIR",
      "password": true
    },
    {
      "type": "promptString",
      "id": "atomic_mail_api_key",
      "description": "ATOMIC_MAIL_API_KEY",
      "password": true
    },
    {
      "type": "promptString",
      "id": "atomic_mail_auth_url",
      "description": "ATOMIC_MAIL_AUTH_URL",
      "password": true
    }
  ],
  "servers": {
    "atomic-mail": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "@atomicmail/mcp-modelcontextprotocol"
      ],
      "env": {
        "ATOMIC_MAIL_CREDENTIALS_DIR": "${input:atomic_mail_credentials_dir}",
        "ATOMIC_MAIL_API_KEY": "${input:atomic_mail_api_key}",
        "ATOMIC_MAIL_AUTH_URL": "${input:atomic_mail_auth_url}"
      }
    }
  }
}

Claude Code (remote)

claude mcp add --transport http atomic-mail "https://mcp.atomicmail.ai/mcp"

The same server is also hosted as a remote MCP endpoint, so nothing runs on your machine.

Config formats checked against the official docs on Oct 7, 2026: modelcontextprotocol.io (opens in a new tab), code.claude.com (opens in a new tab), cursor.com (opens in a new tab), code.visualstudio.com (opens in a new tab).

Environment variables

Variables the server reads at startup.

NameRequiredDescription
ATOMIC_MAIL_CREDENTIALS_DIRsecretNoOverride default credential directory (~/.atomicmail/)
ATOMIC_MAIL_API_KEYsecretNoExisting API key — skips PoW registration
ATOMIC_MAIL_AUTH_URLsecretNoOverride auth service base URL
ATOMIC_MAIL_API_URLNoOverride JMAP API base URL
ATOMIC_MAIL_INBOX_DOMAINNoDefault inbox domain when inboxId has no @ (default: atomicmail.ai)

About Atomic Mail

                           Accounts are free, with a 100 MB storage quota, custom domain included, and rate limits sized for agent workloads.

  • ai
  • ai-agents
  • claude
  • email
  • hermes
  • jmap
  • openclaw
  • proof-of-work

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FAQ

Atomic Mail FAQ

Still curious? Email info@appsgit.com.

What is Atomic Mail?

Atomic Mail is an MCP server that adds messaging tools to AI assistants such as Claude Desktop, Claude Code and Cursor. Programmable email inbox for AI agents — JMAP, PoW auth, stdio MCP server. It has 266 GitHub stars, is released under the MIT license and runs locally with npx -y @atomicmail/mcp-modelcontextprotocol. The source code is at github.com/Atomic-Mail/atomic-mail-agentic.

How do I install the Atomic Mail MCP server?

Add the command npx -y @atomicmail/mcp-modelcontextprotocol to your MCP client: put it in claude_desktop_config.json for Claude Desktop, run claude mcp add for Claude Code, or add it to .cursor/mcp.json (Cursor) or .vscode/mcp.json (VS Code). The snippets on this page are ready to paste.

Is Atomic Mail free?

The server is open source under the MIT license, so running it is free. It needs credentials (ATOMIC_MAIL_CREDENTIALS_DIR, ATOMIC_MAIL_API_KEY and ATOMIC_MAIL_AUTH_URL) for the service it connects to, which may require a paid account.

Is Atomic Mail actively maintained?

The most recent commit was on Sep 27, 2026. The latest release is v0.3.31, published Sep 27, 2026. appsgit only lists MCP servers with a commit in the last six months and re-checks every server daily.