# Nostr Mail Bridge

A bidirectional bridge between legacy email systems and the Nostr protocol.

# Architecture

                         INBOUND (Email → Nostr)
┌─────────────┐      ┌─────────────────┐      ┌────────┐      ┌──────┐
│ Legacy Email│ ───► │ inbound-smtp    │ ───► │ Relays │ ───► │ User │
└─────────────┘      │ or              │      └────────┘      └──────┘
                     │ inbound-mailgun │
                     └─────────────────┘

                         OUTBOUND (Nostr → Email)
┌──────┐      ┌────────┐      ┌────────┐      ┌─────────────┐
│ User │ ───► │ Relays │ ───► │ bridge │ ───► │ Legacy Email│
└──────┘      └────────┘      └────────┘      └─────────────┘

                         DISCOVERY
┌────────┐      GET /.well-known/nostr.json      ┌───────────────┐
│ Client │ ──────────────────────────────────►   │ nip05-service │
└────────┘                                       └───────────────┘

# Components

Component	Description	Port
`bridge-inbound`	Receives emails and publishes to Nostr	25 / 3001
`bridge-outbound`	Listens to Nostr and sends emails	-
`nip05-service`	NIP-05 user discovery	3000
`bridge-plugins`	Email filtering plugins	-

Inbound

Outbound

Plugins

Configuration

Email → Nostr: SMTP server or Mailgun webhooks

Nostr → Email: Subscribe to events and send via SMTP

Extensible plugin system for filtering

Environment variables and settings

# Quick Start with Docker

git clone https://github.com/nogringo/nostr-mail-bridge
cd nostr-mail-bridge
cp .env.example .env
docker-compose up -d

# Services Overview

# Inbound Service

Handles incoming emails from legacy systems:

SMTP Mode: Runs an SMTP server to receive emails directly
Mailgun Mode: Receives webhooks from Mailgun

# Outbound Service

Handles outgoing emails to legacy systems:

Subscribes to gift-wrapped events (kind 1059)
Unwraps NIP-59 encrypted emails
Sends via SMTP or Mailgun API

# NIP-05 Service

Provides user discovery via .well-known/nostr.json:

GET /.well-known/nostr.json?name=alice

{
  "names": {
    "alice": "<pubkey_hex>"
  }
}

# Self-Hosted Setup

For a fully self-hosted setup without external services:

┌──────────────────────────────────────────────────┐
│                  Your Server                     │
│                                                  │
│  ┌──────────────┐  ┌────────┐  ┌──────────────┐  │
│  │ inbound-smtp │  │ bridge │  │ nip05-service│  │
│  │    :25       │  │        │  │    :3000     │  │
│  └──────────────┘  └────────┘  └──────────────┘  │
│         │              │              │          │
│         └──────────────┼──────────────┘          │
│                        │                         │
│                   ┌────────┐                     │
│                   │ Postfix│ (or any MTA)        │
│                   └────────┘                     │
└──────────────────────────────────────────────────┘

Required DNS configuration:

MX record pointing to your server
A/AAAA record for your mail domain