zerosmtp
A free SMTP relay that still takes a username and password, for devices that cannot do OAuth 2.0.
Install
npmstdio
npx -y zerosmtp-mcp Client config (Claude Desktop, Cursor, Windsurf and most MCP clients)
{
"mcpServers": {
"io-github-msgwing-zerosmtp": {
"command": "npx",
"args": [
"-y",
"zerosmtp-mcp"
]
}
}
}Source: official MCP Registry record · registry name io.github.msgwing/zerosmtp · published 2026-09-01 · updated 2026-09-01. Not an endorsement; review the code before connecting it to anything sensitive.