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Elephant

Elephant – a privacy-first, open-source messaging application made with Go and Flutter. Elephant supports secure authentication, user discovery, and real-time chat over WebSocket, with all communication TLS-protected between client and server.

Tech Stack

Layer	Technology
Backend	Go (chi, pgx, gorilla/websocket, golang-jwt, argon2)
Mobile	Flutter (http, web_socket_channel, provider, sqflite)
Database	PostgreSQL 16
CI/CD	GitHub Actions, Docker Compose, GHCR

GitHub Releases (Mobile Apps)

If you just want to run the client application or get a production-ready backend binary without setting up a build environment, head straight over to our GitHub Releases Page.

Here you will find:

• Client Installers: Pre-built application packages (.apk for Android ) ready for deployment.

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Quick Start (Docker/Podman)

The fastest way to run Elephant is by pulling the published image — no Go toolchain required.

Pulling image from Docker Hub

docker run --name elephant-server \
  -e PORT=3000 \
  -e POSTGRES_HOST=host.docker.internal \
  -e POSTGRES_PORT=3000 \
  -e POSTGRES_USER=your_db_user \
  -e POSTGRES_PASSWORD=your_db_password \
  -e POSTGRES_DB=your_db_name \
  -e JWT_SECRET=a_secure_32_character_secret_key_phrase \
  -p 3000:3000 \
  -d commandlinecoding/elephant:latest

Pulling image from Github GHCR

podman run --name elephant-server \
  -e PORT=3000 \
  -e POSTGRES_HOST=host.containers.internal \
  -e POSTGRES_PORT=3000 \
  -e POSTGRES_USER=your_db_user \
  -e POSTGRES_PASSWORD=your_db_password \
  -e POSTGRES_DB=your_db_name \
  -e JWT_SECRET=a_secure_32_character_secret_key_phrase \
  -p 3000:3000 \
  -d ghcr.io/commandlinecoding/elephant:latest

Once running, verify the server is healthy:

curl http://HOST:PORT/api/health

You should see:

{"success":true,"data":{"postgres":"up","timestamp":"..."}}

Local Development Setup

If you're contributing to the backend and want to build from source instead of pulling the published image, use the dev compose override:

# Clone the repo for the compose file and .env template
git clone https://github.com/commandlinecoding/elephant.git
cd elephant
 
# Copy and fill in environment variables
cp .env.example .env
 
# Start the stack
docker compose up -d
# or: podman-compose up -d

This builds the server image from server/Dockerfile on every run instead of pulling from GHCR, so your local changes are reflected immediately.

Running the backend without Docker

cd server
go mod download
go run main.go

Make sure PostgreSQL is running and reachable using the values in your .env file (POSTGRES_HOST, POSTGRES_PORT, POSTGRES_USER, POSTGRES_PASSWORD, POSTGRES_DB).

Running database migrations

cd server
psql "postgres://$POSTGRES_USER:$POSTGRES_PASSWORD@$POSTGRES_HOST:$POSTGRES_PORT/$POSTGRES_DB" \
for migration in /app/migrations/*_up.sql; do
    filename=$(basename "$migration")
    already_applied=$(psql "${DB_URL}" -tAc \
        "SELECT COUNT(*) FROM schema_migrations WHERE filename = '${filename}'")
    if [ "$already_applied" = "0" ]; then
        echo "Applying ${filename}..."
        psql "${DB_URL}" -f "$migration"
        psql "${DB_URL}" -c \
            "INSERT INTO schema_migrations (filename) VALUES ('${filename}')"
        echo "${filename} applied."
    else
        echo "${filename} already applied, skipping."
    fi
done

Running the mobile app

cd mobile
flutter pub get
flutter run

Environment Variables

Variable	Description	Default
HOST	Server bind address	127.0.0.1
PORT	Server port	3000
POSTGRES_USER	Database username	postgres
POSTGRES_PASSWORD	Database password	—
POSTGRES_DB	Database name	myapi_db
POSTGRES_PORT	Database port	5432
POSTGRES_HOST	Database host	localhost
JWT_SECRET	Secret key for signing JWTs	—
ARGON_MEMORY	Argon2id memory cost (KB)	65536
ARGON_ITERATIONS	Argon2id iteration count	3
ARGON_PARALLELISM	Argon2id parallelism degree	2

See .env.example for a starting template.

API

Checkout the API document

Registration note

Usernames are normalized to lowercase and assigned a random 4-digit discriminator on registration to avoid collisions, e.g. registering as abc may result in the stored username abc.4821. Use the full discriminated username returned in the registration response when logging in.

Testing

Run the full backend test suite (unit + integration):

cd server
go vet ./...
go test -v ./...

Integration tests under server/tests/ expect a running server and database. Start the stack first, then run:

HOST=$HOST PORT=$PORT go test -v ./tests/...

CI/CD

Docker images are built and published to both GHCR and Docker Hub automatically on every version tag push. Android APKs are built and attached to GitHub Releases automatically on every version tag push.

Project Structure

elephant/
├── .github/                 # GitHub Actions workflows
├── docs/                    # Project documentation
├── mobile/                  # Flutter client
│   ├── android/
│   ├── ios/
│   ├── lib/
│   ├── assets/
│   ├── pubspec.yaml
│   └── README.md
├── server/                  # Go backend
│   ├── config/              # DB, JWT, Argon2, CORS configuration
│   ├── controllers/         # HTTP handlers
│   ├── env/                 # Environment variable loading
│   ├── errors/              # Sentinel error definitions
│   ├── middlewares/         # Auth, CORS, logging, rate limiting
│   ├── migrations/          # SQL migration files
│   ├── models/              # Data models
│   ├── repository/          # Database access layer
│   ├── routes/              # Route definitions
│   ├── services/            # Business logic (auth, users, JWT, WebSocket)
│   ├── tests/               # Integration tests
│   └── Dockerfile
├── compose.yaml              # Default: pulls published image
├── compose.dev.yaml          # Override: builds server from source
├── .env.example              # Environment variable template
└── LICENSE

Contributing

Checkout CONTRIBUTING.md for more information

License

See LICENSE for details.