MailStream for Claude.ai
app.mailstream/mailstream
The first MCP server for physical mail: send postcards and letters, manage lists and campaigns.
client:Claude.ai
transport:streamable-http
Install MailStream in Claude.ai
Settings → Connectors → Add custom connector
https://my.mailstream.app/mcpClaude on the web takes a remote URL and completes OAuth in the browser. For a packaged server use Claude Desktop or Claude Code instead. Claude.ai docs