> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/iii-hq/iii/llms.txt
> Use this file to discover all available pages before exploring further.

# Installation

> Install the iii engine using curl, Docker, or build from source

# Installing iii

iii runs as a single binary that orchestrates your backend functions and triggers. Choose your preferred installation method below.

## Quick Install (Recommended)

The fastest way to get started is with the installation script:

<CodeGroup>
  ```bash Default theme={null}
  curl -fsSL https://install.iii.dev/iii/main/install.sh | sh
  ```

  ```bash Custom Directory theme={null}
  curl -fsSL https://install.iii.dev/iii/main/install.sh | BIN_DIR=$HOME/.local/bin sh
  ```

  ```bash Specific Version theme={null}
  curl -fsSL https://install.iii.dev/iii/main/install.sh | sh -s -- v0.6.3
  ```
</CodeGroup>

<Tip>
  The installation script automatically detects your platform (Linux, macOS, Windows) and architecture (x86\_64, ARM64).
</Tip>

### Verify Installation

After installation, verify that iii is available:

```bash theme={null}
command -v iii && iii --version
```

Expected output:

```
/usr/local/bin/iii
iii v0.7.0
```

## Docker Installation

iii is available as a Docker image for containerized deployments.

### Pull the Image

```bash theme={null}
docker pull iiidev/iii:latest
```

### Run with Docker

<Steps>
  <Step title="Create a config file (optional)">
    If you need custom module configuration, create a `config.yaml` file:

    ```yaml config.yaml theme={null}
    modules:
      - class: modules::rest_api::RestApiCoreModule
        config:
          host: 0.0.0.0
          port: 3111
      - class: modules::observability::OtelModule
        config:
          enabled: true
          level: info
    ```
  </Step>

  <Step title="Run the container">
    ```bash theme={null}
    docker run -p 3111:3111 -p 49134:49134 \
      -v ./config.yaml:/app/config.yaml:ro \
      iiidev/iii:latest
    ```

    <Note>
      If you don't provide a config file, iii loads default modules: HTTP, Queue, Cron, Stream, and Observability.
    </Note>
  </Step>

  <Step title="Verify the engine is running">
    The engine exposes several ports:

    | Port  | Service                        |
    | ----- | ------------------------------ |
    | 49134 | WebSocket (worker connections) |
    | 3111  | HTTP API                       |
    | 3112  | Stream API                     |
    | 9464  | Prometheus metrics             |
  </Step>
</Steps>

### Production Docker Deployment

For production environments, use a hardened configuration:

```bash theme={null}
docker run --read-only --tmpfs /tmp \
  --cap-drop=ALL --cap-add=NET_BIND_SERVICE \
  --security-opt=no-new-privileges:true \
  -v ./config.yaml:/app/config.yaml:ro \
  -p 3111:3111 -p 49134:49134 -p 3112:3112 -p 9464:9464 \
  iiidev/iii:latest
```

<Warning>
  Production images use distroless runtime (no shell, minimal attack surface) and run as non-root user.
</Warning>

## Docker Compose

For a complete stack with Redis and RabbitMQ:

<Steps>
  <Step title="Create docker-compose.yml">
    ```yaml docker-compose.yml theme={null}
    services:
      iii:
        image: iiidev/iii:latest
        ports:
          - "49134:49134"  # WebSocket
          - "3111:3111"    # REST API
          - "3112:3112"    # Stream API
          - "9464:9464"    # Metrics
        volumes:
          - ./config.yaml:/app/config.yaml:ro
        environment:
          - RUST_LOG=info
        depends_on:
          redis:
            condition: service_healthy
        restart: unless-stopped

      redis:
        image: redis:7-alpine
        ports:
          - "6379:6379"
        volumes:
          - redis_data:/data
        healthcheck:
          test: ["CMD", "redis-cli", "ping"]
          interval: 5s
          timeout: 3s
          retries: 5
        restart: unless-stopped

    volumes:
      redis_data:
    ```
  </Step>

  <Step title="Start the stack">
    ```bash theme={null}
    docker compose up -d
    ```
  </Step>

  <Step title="Check status">
    ```bash theme={null}
    docker compose ps
    docker compose logs iii
    ```
  </Step>
</Steps>

<Tip>
  Queue and Stream modules require Redis at `redis://localhost:6379` by default. Override with environment variables in your config.
</Tip>

## Build from Source

For development or custom builds:

<Steps>
  <Step title="Install Rust toolchain">
    ```bash theme={null}
    curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
    ```
  </Step>

  <Step title="Clone the repository">
    ```bash theme={null}
    git clone https://github.com/iii-hq/iii.git
    cd iii
    ```
  </Step>

  <Step title="Build the binary">
    ```bash theme={null}
    cargo build --release
    ```

    The binary will be at `target/release/iii`.
  </Step>

  <Step title="Run the engine">
    ```bash theme={null}
    cargo run
    # Or with config:
    cargo run -- --config config.yaml
    ```
  </Step>
</Steps>

### Development Commands

```bash theme={null}
# Watch mode (requires cargo-watch)
make watch

# Lint and format
cargo fmt && cargo clippy -- -D warnings

# Run tests
cargo test

# Build Docker images locally
docker build -t iii:local .                        # production
docker build -f Dockerfile.debug -t iii:debug .    # debug
```

## Environment Configuration

iii supports environment variable expansion in config files:

```yaml config.yaml theme={null}
modules:
  - class: modules::queue::QueueModule
    config:
      adapter:
        class: modules::queue::RedisAdapter
        config:
          redis_url: ${REDIS_URL:redis://localhost:6379}
```

The syntax `${VAR:default}` reads from environment or uses the default value.

## Next Steps

<CardGroup cols={2}>
  <Card title="Start the Engine" icon="power-off" href="/quickstart#start-the-engine">
    Learn how to start iii and connect your first worker
  </Card>

  <Card title="Install an SDK" icon="download" href="/sdks/nodejs">
    Install the Node.js, Python, or Rust SDK to write functions
  </Card>

  <Card title="Configure Modules" icon="sliders" href="/deployment/configuration">
    Customize HTTP, Queue, Cron, Stream, and other modules
  </Card>

  <Card title="Production Setup" icon="shield" href="/deployment/production">
    Hardening, monitoring, and scaling for production
  </Card>
</CardGroup>

<Note>
  **Default Modules**: Without a config file, iii loads HTTP, Queue, Cron, Stream, and Observability modules. Queue and Stream expect Redis at `redis://localhost:6379`.
</Note>