Bang!mail

Overview

• Address Formatuser!domain
• TransportSSH
• EncryptionAES-256-GCM via BANGMAIL_KEY
• Message FormatJSON
• Storage ModelEphemeral — unread messages only

Address Format

Server Key

BANGMAIL_KEY is a text string used for encryption and decryption.

• Set viaenvironment variable
• Shared externallynever
• Purposeencrypts stored messages at rest
• Requiredserver won't run without it

Message Encryption

• AlgorithmAES-256-GCM
• Key derivationSHA-256 from BANGMAIL_KEY (or raw)
• Nonce / IVrandom 12 bytes per message
• Client-sideoptional pre-encryption before transport

Sending a Message

1. Client opens an SSH session to target domain on port 2222 (default)
2. Client runs a remote command over SSH: bangmail-receive [recipient]
3. Client streams the encrypted message payload over stdin

The server reads the stream, validates the command, and stores the message encrypted in the user's queue.

CLI — Send

bangmail send "neo!neoapps.dev" \
          --subject "yo" \
          --body "meet me at the base" \
          --from "sarah!sarah.dev"

Message Format

Receiving Messages

1. Client SSHes into their own server and runs bangmail-fetch [username]
2. Server decrypts and streams all unread messages as a JSON array
3. Messages are deleted from server immediately after delivery

CLI — Fetch

bangmail fetch "sarah!sarah.dev" > inbox.json
      

Message Retention

• At restAES-256-GCM encrypted
• After readdeleted immediately
• TTLoptional (e.g. 24h expiry)

Authentication

• SSH authnot required for inbound messages
• Rate limitingoptional — key or IP based
• Security modelencryption layer, not transport

bangmaild

The server daemon. Exposes an SSH server on a configurable port and handles all message I/O.

• Listens onconfigurable port (default 2222)
• Acceptsbangmail-receive [username]
• Acceptsbangmail-fetch [username]
• Storagereads/writes encrypted files to inbox
• Cleanupdeletes messages after delivery

Philosophy

Feature Summary