MCP Collection

nPubMail MCP Server

An email inbox for AI agents, owned by a Nostr key: no signup, no password, no API key.

Communication MIT license Added Nov 13, 2026 Self-hosted

nPubMail is a Communication MCP (Model Context Protocol) server: An email inbox for AI agents, owned by a Nostr key: no signup, no password, no API key. It is MIT-licensed and self-hosted from its source repository. Listed on MCP Collection since November 2026.

About nPubMail

nPubMail gives an agent its own email address. The account is a Nostr key, so there is no signup. The local stdio server npubmail-mcp (Go, MIT) lets the agent read its inbox, pick up verification codes, reply and send. Free: mailbox, aliases, receiving, replies to verified senders and mail to other npubmail addresses. Mailing a new outside address costs 10 sats per recipient via a Lightning invoice (HTTP 402). Limits: 50 recipients/day, 7-day retention. Beta on a new domain: outgoing mail may land in spam. Needs a local program, so it does not work inside claude.ai/ChatGPT web. Official MCP Registry: com.npubmail/npubmail.

How to connect nPubMail to Claude, Cursor or VS Code

nPubMail is self-hosted. Install it from the source repository, then register its start command in your MCP client's config (Claude Code, Cursor, Windsurf or VS Code).

{
  "mcpServers": {
    "npubmail": {
      "command": "<start command from the README>",
      "args": []
    }
  }
}

The exact command (often npx, uvx or docker) is in the project README at github.com/obvioussummer46/npubmail.

nPubMail FAQ

What is nPubMail?

nPubMail is a Model Context Protocol (MCP) server in the Communication category. An email inbox for AI agents, owned by a Nostr key: no signup, no password, no API key. MCP servers expose tools that AI assistants like Claude can call during a conversation.

How do I use nPubMail with Claude or Cursor?

nPubMail is self-hosted. Install it from the source repository, then register its start command in your MCP client's config (Claude Code, Cursor, Windsurf or VS Code).

Is nPubMail free to use?

nPubMail is published under the MIT license, so the software itself is free to run. Hosted or API-backed servers may have their own usage tiers; check the project homepage.

Where is the source code for nPubMail?

The source is at github.com/obvioussummer46/npubmail.

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