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Mycel

A messenger that works without the internet.

Mycel is a delay-tolerant mesh messenger for Android. It sends messages by passing them between nearby phones until they reach their destination - no cell towers, no Wi-Fi, no servers required.

Where Do You Want to Go?

I want to... Start here
Use Mycel Getting Started - Install, set up, send messages
Understand how it works How It Works - Mesh networking, delivery, transports
Dive into technical details Deep Dive - Protocols, algorithms, architecture
Learn about security Security - Encryption, privacy, threat model

Why Mycel?

Traditional messengers need the internet to work. When the network goes down - during emergencies, in remote areas, or when infrastructure is blocked - communication stops.

Mycel keeps you connected by turning every phone into a relay. Your message hops from device to device, carried by people moving through the world, until it reaches your friend.

Perfect for:

  • Emergencies - Stay in touch when networks are down
  • Remote areas - Communicate without cell coverage
  • Events & festivals - Message friends in crowded areas with overloaded networks
  • Privacy-conscious users - No servers storing your metadata

How It Works (30 Seconds)

sequenceDiagram
    participant A as Your Phone
    participant B as Nearby Phone
    participant C as Friend's Phone
    A->>B: Message handed off
    Note right of B: Carries message<br/>until next encounter
    B->>C: Message delivered
    C-->>A: Delivery confirmed
  1. You send a message - Your phone looks for nearby Mycel users
  2. Message hops through the mesh - Each phone stores and forwards your message
  3. Delivery happens - When a chain of connections reaches your friend, the message arrives
  4. You get confirmation - An acknowledgment travels back to confirm delivery

Delivery Time Expectations

Messages can arrive in seconds (if nearby) or hours/days (if far away). This is normal - Mycel trades instant delivery for the ability to work anywhere.

Key Features

Feature Description
Offline-First Works without any internet connection
End-to-End Encrypted Only you and your recipient can read messages
No Central Server Messages travel peer-to-peer, no company in the middle
Multi-Transport Uses Bluetooth, Wi-Fi Direct, and optional internet relay
Store-and-Forward Messages persist until delivered, even if it takes days

Quick Start

  1. Download the APK from GitHub Releases
  2. Install and set up on your Android device (requires sideloading)
  3. Send your first message

Keep Updated

For automatic updates, use Obtainium - it checks GitHub for new releases and installs them for you.

Learning Paths

For Users

  1. Install the app
  2. Grant permissions
  3. Send your first message
  4. Understand delivery times
  5. Battery & background tips

For Developers

  1. Architecture overview
  2. Message flow
  3. Routing algorithms
  4. Transport abstractions

Open Source

Mycel is open source software. Documentation source: github.com/ethene/mycel-docs.

Mycel v2.1.1