Nostr Mail Settings

This document defines the protocol for storing and synchronizing user settings across devices in Nostr Mail using NIP-78 application-specific data.

Overview

User settings are stored as replaceable parameterized events (kind 30078). This enables seamless synchronization across multiple devices while maintaining privacy through encryption.

Event Kind

Kind 30078: Application-Specific Data

Settings use NIP-78 replaceable parameterized events with the d tag for namespacing.

Public Settings

Public settings are stored unencrypted and can be read by anyone.

{
  "kind": 30078,
  "pubkey": "<user_pubkey>",
  "tags": [["d", "nostr-mail/settings"]],
  "content": "{\"dm_copy\": true}"
}

Fields

Private Settings

Private settings MUST be encrypted to self using NIP-44.

{
  "kind": 30078,
  "pubkey": "<user_pubkey>",
  "tags": [["d", "nostr-mail/settings/private"]],
  "content": "<nip44_encrypted_json>"
}

Decrypted Content

After decryption, the content contains:

Identities

Identities are user-defined “From” addresses stored as RFC 5322 formatted strings. Each entry can be used directly in the From: header without any transformation.

Format examples:

• "Alice Real <npub1abc...@nostr.mail>" — name + address
• "npub1abc...@bridge.com" — address only (no name)
• "Pseudo <alice@example.com>" — custom name + legacy email

Behavior:

• If identities is empty or absent, clients SHOULD auto-generate available addresses from npub@nostr and configured bridges
• The first identity (index 0) is the default “From” address

Example (Decrypted)

{
  "signature": "Sent via Nostr Mail",
  "bridges": ["nostr.mail", "bridge.example.com"],
  "identities": [
    "Alice Real <npub1abc...@nostr.mail>",
    "<npub1abc...@bridge.com>",
    "Pseudo <alice@example.com>"
  ]
}

Example (Encrypted Event)

{
  "kind": 30078,
  "tags": [["d", "nostr-mail/settings/private"]],
  "content": "<nip44_encrypted_blob>"
}