Side-by-side comparison of two Model Context Protocol servers — install paths, tools, quality signals, and directory engagement so you can pick the right one for Claude, Cursor, and other MCP clients.
Send physical mail with Solana payments — AI agents can compose, price, and send letters and postcards via cryptocurrency.
EU-hosted email API exposed as MCP tools — send transactional and marketing email, manage contacts and segments, run broadcasts, render templates, and read analytics from Claude/Cursor. GDPR compliant, EU-only data residency (Germany + Finland). npx -y @poststack.dev/mcp.