Mailosaur MCP

A full-featured Model Context Protocol server for Mailosaur email and SMS testing.

Features

• List, search, wait for, retrieve, create, forward, reply to, and delete messages.
• Manage Mailosaur servers and generate test email addresses.
• Download EML files and attachments as base64 content.
• Generate and download email preview screenshots.
• Run spam and deliverability analysis.
• Inspect account limits and transaction usage.
• Create virtual security devices and retrieve TOTP codes.

The implementation is based on the official Mailosaur API and Node.js client surface. See Mailosaur API docs, Mailosaur Node.js docs, and Mailosaur email previews docs.

Setup

npm install
npm run build

Set your Mailosaur API key:

export MAILOSAUR_API_KEY="your_api_key"

MCP configuration

{
  "mcpServers": {
    "mailosaur": {
      "command": "node",
      "args": ["/absolute/path/to/mailosaur-mcp/dist/index.js"],
      "env": {
        "MAILOSAUR_API_KEY": "your_api_key"
      }
    }
  }
}

Local development

npm run typecheck
npm run build

Run directly during development:

MAILOSAUR_API_KEY="your_api_key" npm run dev

Tools

• mailosaur_messages_get
• mailosaur_messages_list
• mailosaur_messages_search
• mailosaur_messages_get_by_id
• mailosaur_messages_create
• mailosaur_messages_forward
• mailosaur_messages_reply
• mailosaur_messages_delete
• mailosaur_messages_delete_all
• mailosaur_messages_generate_previews
• mailosaur_servers_list
• mailosaur_servers_create
• mailosaur_servers_get
• mailosaur_servers_get_password
• mailosaur_servers_update
• mailosaur_servers_delete
• mailosaur_servers_generate_email_address
• mailosaur_files_get_email
• mailosaur_files_get_attachment
• mailosaur_files_get_preview
• mailosaur_analysis_spam
• mailosaur_analysis_deliverability
• mailosaur_previews_list_email_clients
• mailosaur_devices_list
• mailosaur_devices_create
• mailosaur_devices_otp
• mailosaur_devices_delete
• mailosaur_usage_limits
• mailosaur_usage_transactions

Destructive tools require confirm: true.

Repository Skill

This repository includes a Codex skill at skills/mailosaur-mcp-builder. Use it when extending this MCP, auditing tool coverage against Mailosaur docs, or building another Mailosaur MCP implementation.