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# Nostr Mail Protocol

The Nostr Mail protocol defines how emails are transmitted over the Nostr network using Kind 1301 events.

# Goal

Remove gatekeepers from email. Use Nostr as transport instead of SMTP between users.

# Event Kind

# Kind 1301: Email 

{
  "kind": 1301,
  "pubkey": "<sender_npub>",
  "tags": [
    ["p", "<recipient_npub>"]
  ],
  "content": "<RFC 2822 email>"
}

The content is a standard email (RFC 2822). Nostr is just the delivery mechanism.

# Example

# Nostr-to-Nostr Email 

{
  "kind": 1301,
  "pubkey": "npub1alice...",
  "tags": [
    ["p", "npub1bob..."]
  ],
  "content": "From: alice@bridge.mail\nTo: bob@bridge.mail\nSubject: Hello\nDate: Sat, 28 Dec 2024 12:00:00 +0000\n\nHey Bob, how are you?"
}

# Sending to Legacy Email

When the recipient has no npub (e.g., alice@gmail.com), send to a bridge:

{
  "kind": 1301,
  "pubkey": "npub1bob...",
  "tags": [
    ["p", "<bridge_npub>"]
  ],
  "content": "From: bob@bridge.mail\nTo: alice@gmail.com\nSubject: Hello\nDate: Sat, 28 Dec 2024 12:00:00 +0000\n\nHey Alice!"
}

# How it works

  1. p tag = bridge's npub (the bridge receives the event)
  2. To: header in content = legacy recipient
  3. Bridge extracts To: and sends via SMTP

# Receiving from Legacy Email

When alice@gmail.com sends to bob@bridge.mail:

{
  "kind": 1301,
  "pubkey": "<bridge_npub>",
  "tags": [
    ["p", "npub1bob..."]
  ],
  "content": "From: alice@gmail.com\nTo: bob@bridge.mail\nSubject: Hello\nDate: Sat, 28 Dec 2024 12:00:00 +0000\n\nHey Bob!"
}

# How it works

  1. Bridge receives SMTP email
  2. Bridge looks up npub for bob@bridge.mail
  3. Bridge creates event and publishes to Bob's NIP-17 DM relays

# Privacy

Emails are gift-wrapped using NIP-59 so relays only see:

  • Recipient pubkey
  • Encrypted blob

The actual email content is never visible to relays.

# Bridge Role

The bridge converts transport only:

Direction From To Process
Inbound SMTP Nostr event Parses To: to find npub
Outbound Nostr event SMTP Parses To: to find legacy address

# Bridge Discovery

Use NIP-05 to find a bridge's npub:

GET https://bridge.mail/.well-known/nostr.json?name=_smtp

{
  "names": {
    "_smtp": "<bridge_npub_hex>"
  }
}

# Discovery Flow

  1. User selects a bridge (e.g., bridge.mail)
  2. Client queries _smtp@bridge.mail via NIP-05
  3. Client gets bridge npub
  4. Client sends kind 1301 event with p = bridge npub

# Relay Discovery

Use NIP-17 DM relays (kind 10050) for message delivery.

The client should:

  1. Look up recipient's DM relay list (kind 10050)
  2. Publish the gift-wrapped event to those relays