True P2P Email on Top of Yggdrasil Network

We're taught that email must go through servers. Why? Because the Internet was built around centralized infrastructure. Every email you send travels through multiple servers - your provider's server, maybe a few relay servers, and finally your recipient's provider's server. Each hop is a potential point of surveillance, censorship, or failure.

Even "encrypted" email solutions still rely on these centralized servers. They encrypt the message content but the metadata - who you're talking to, when, how often - is visible to anyone watching the servers.

But there is a network, called Yggdrasil, that gives everyone a free IPv6 and doesn't need a blessing from your ISP. We finally have this possibility to use true P2P email. And moreover, this network has strong encryption to protect all data that flows from one IP to another.

Tyr brings true peer-to-peer email to your Android device using these unusual conditions. Unlike traditional email clients, Tyr doesn't need:

• ❌ Centralized mail servers (the connections are straight P2P)
• ❌ Message encryption layers (the network takes care of that)
• ❌ Port forwarding or STUN/TURN servers (Yggdrasil handles NAT traversal)

graph LR
    A[DeltaChat/ArcaneChat] -->|SMTP/IMAP| B[Tyr Service]
    B -->|Yggmail Protocol| C[Yggdrasil Network]
    C -->|P2P Encrypted| D[Recipient's Tyr]
    D -->|SMTP/IMAP| E[Recipient's Chat App]

Tyr runs a complete email server right on your Android device, using the Yggdrasil network for transport. The Yggmail mail server (built in Go) is embedded as a library inside the app and runs as a foreground service.

On top of Yggdrasil, it provides standard SMTP and IMAP protocols on localhost (127.0.0.1:1025 and 127.0.0.1:1143). Any email client can connect to these ports - but we recommend DeltaChat or ArcaneChat for the best P2P messaging experience.

Every Tyr installation generates unique Ed25519 cryptographic keys. Your mail address is derived from your public key:

<64-hex-characters>@yggmail

This means your identity is cryptographically verifiable and cannot be spoofed.

1. Install Tyr and complete the onboarding (set password, configure peers)
2. Start the Yggmail service in Tyr
3. Install DeltaChat or ArcaneChat
4. In Tyr's main screen, tap "Setup DeltaChat/ArcaneChat"
5. Tyr will automatically open your chat app with pre-configured settings
6. Complete the setup and start chatting!

If automatic setup doesn't work:

1. Complete Tyr onboarding and start the service
2. Copy your mail address from Tyr's main screen (looks like abc123...@yggmail)
3. In DeltaChat/ArcaneChat, create a new profile
4. Tap "Use a different server"
5. Enter your Yggmail address and the password you set in Tyr
6. Tap "✓" to complete setup

Important: Tyr must be running for your chat app to send and receive messages. Enable auto-start in Tyr settings for seamless experience.

• Password Encryption: Android Keystore System with AES-256-GCM
• Automatic Keystore Recovery: Handles Android Keystore issues on Samsung and other devices
• Network Encryption: All P2P communications encrypted by Yggdrasil Network
• Local-Only Access: SMTP/IMAP ports bound to localhost only
• Cryptographic Identity: Ed25519 keys ensure your mail address cannot be spoofed
• Encrypted Backups: Configuration and keys backed up with password protection

• Android Studio (latest version)
• JDK 17
• Android SDK (API 23-36)
• Go 1.21+ and gomobile (only if rebuilding yggmail.aar)

# Clone the repository
git clone https://github.com/JB-SelfCompany/Tyr.git
cd Tyr

# Build debug APK
./gradlew assembleDebug

# Install to connected device
./gradlew installDebug

APKs will be in app/build/outputs/apk/debug/ or app/build/outputs/apk/release/

cd ../yggmail/mobile

# Windows
..\build-android.bat

# Unix
gomobile bind -target=android -androidapi 23 -javapkg=com.jbselfcompany.tyr -ldflags="-checklinkname=0" -o yggmail.aar .

Then copy yggmail.aar to Tyr/app/libs/

• Yggmail: The mail transfer agent that powers Tyr
• Mimir: P2P messenger on Yggdrasil (sister project)
• Yggdrasil Network: The mesh network infrastructure
• DeltaChat: Recommended email-based messenger client
• ArcaneChat: Alternative email-based messenger client

Tyr is open source software. The Yggmail library uses Mozilla Public License v. 2.0.

See LICENSE file for full details.

Censorship Circumvention: Connect to any of hundreds of available Yggdrasil nodes, host your own, or even build a private network. Email freedom is literally in your hands.

Privacy by Design: No metadata collection, no server logs, no third-party surveillance. Your conversations belong to you.

Decentralization: No single point of failure, no corporate control. True peer-to-peer architecture.