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

# leo devnet

> Launch and manage a local Aleo devnet with validators and clients

The `leo devnet` command launches and manages a local Aleo development network using snarkOS, providing a full-featured environment for testing Leo programs.

## Syntax

```bash theme={null}
leo devnet [OPTIONS]
```

## Options

### Network Configuration

<ParamField path="--num-validators" type="number" default={4}>
  Number of validator nodes to run.
</ParamField>

<ParamField path="--num-clients" type="number" default={2}>
  Number of client nodes to run.
</ParamField>

<ParamField path="-n, --network" type="string" default="testnet">
  Network type: `mainnet`, `testnet`, or `canary`.
</ParamField>

### Storage Options

<ParamField path="--storage" type="string" default="./">
  Ledger and log root directory.
</ParamField>

<ParamField path="--clear-storage" type="boolean" default={false}>
  Remove existing devnet storage before starting.
</ParamField>

<ParamField path="--clean-only" type="boolean" default={false}>
  Only clean devnet storage (ledgers, node data, logs) without starting.
</ParamField>

### snarkOS Configuration

<ParamField path="--snarkos" type="string">
  Path to snarkOS binary. If not found, use `--install` to build it at this path.
</ParamField>

<ParamField path="--snarkos-features" type="string[]">
  Required features for snarkOS (comma-separated). Example: `test_network`
</ParamField>

<ParamField path="--snarkos-version" type="string">
  Required version of snarkOS. Defaults to latest version on crates.io.
</ParamField>

<ParamField path="--install" type="boolean" default={false}>
  (Re)install snarkOS at the provided `--snarkos` path with `--snarkos-features`.
</ParamField>

### Port Configuration

<ParamField path="--rest-port" type="number">
  Base REST port. Each node uses base + node\_index.

  Default for validator 0: `3030`
</ParamField>

<ParamField path="--node-port" type="number">
  Base node port. Each node uses base + node\_index.
</ParamField>

<ParamField path="--bft-port" type="number">
  Base BFT port. Each node uses base + node\_index.
</ParamField>

<ParamField path="--metrics-port" type="number">
  Base metrics port. Each validator uses base + node\_index.
</ParamField>

### Consensus Options

<ParamField path="--consensus-heights" type="string">
  Custom consensus heights (comma-separated). The `test_network` feature must be enabled.

  Can also be set via `CONSENSUS_VERSION_HEIGHTS` environment variable.
</ParamField>

### Display Options

<ParamField path="--tmux" type="boolean" default={false}>
  Run nodes in tmux (Unix only). Allows easy monitoring of individual nodes.
</ParamField>

<ParamField path="--verbosity" type="number" default={1}>
  snarkOS verbosity level (0-4):

  * 0: Error only
  * 1: Warn
  * 2: Info
  * 3: Debug
  * 4: Trace
</ParamField>

### Additional Options

<ParamField path="-y, --yes" type="boolean" default={false}>
  Skip confirmation prompts and proceed with devnet startup.
</ParamField>

## Examples

### Start Default Devnet

```bash theme={null}
leo devnet
```

Starts a devnet with:

* 4 validators
* 2 clients
* Testnet configuration
* REST endpoint at `http://localhost:3030`

Output:

```
🚀 Starting Aleo Devnet
──────────────────────────────────────────────
📊 Configuration:
  Validators:       4
  Clients:          2
  Network:          testnet
  Storage:          ./
  snarkOS:          /path/to/snarkos

🔌 Endpoints:
  Validator 0:      http://localhost:3030 (REST)
  Validator 1:      http://localhost:3031 (REST)
  Validator 2:      http://localhost:3032 (REST)
  Validator 3:      http://localhost:3033 (REST)

Do you want to proceed? [y/N]: y

🟢 Validator 0 started (PID: 12345)
🟢 Validator 1 started (PID: 12346)
🟢 Validator 2 started (PID: 12347)
🟢 Validator 3 started (PID: 12348)
🔵 Client 0 started (PID: 12349)
🔵 Client 1 started (PID: 12350)

✅ Devnet is running!
   Press Ctrl+C to stop.
```

### Start with Custom Node Count

```bash theme={null}
leo devnet --num-validators 6 --num-clients 4
```

### Start with tmux

```bash theme={null}
leo devnet --tmux
```

Each node runs in a separate tmux pane for easy monitoring:

```bash theme={null}
# Attach to tmux session
tmux attach -t leo-devnet

# Navigate between panes
Ctrl+B then arrow keys
```

### Start with Custom Storage

```bash theme={null}
leo devnet --storage ./my-devnet
```

### Clear Storage Before Starting

```bash theme={null}
leo devnet --clear-storage
```

<Warning>
  This deletes all existing ledger data. Use with caution.
</Warning>

### Clean Storage Only

```bash theme={null}
leo devnet --clean-only
```

Removes devnet storage without starting nodes.

### Install and Use Specific snarkOS Version

```bash theme={null}
leo devnet \
  --snarkos ./bin/snarkos \
  --snarkos-version 4.1.0 \
  --snarkos-features test_network \
  --install
```

This will:

1. Install snarkOS 4.1.0 with `test_network` feature
2. Save binary to `./bin/snarkos`
3. Use it to start the devnet

### Start with Custom Ports

```bash theme={null}
leo devnet \
  --rest-port 4000 \
  --node-port 5000 \
  --bft-port 6000
```

Validator 0 will use:

* REST: `4000`
* Node: `5000`
* BFT: `6000`

Validator 1 will use:

* REST: `4001`
* Node: `5001`
* BFT: `6001`

And so on...

### Start with Custom Consensus Heights

```bash theme={null}
leo devnet --consensus-heights 0,100,200
```

Or via environment variable:

```bash theme={null}
CONSENSUS_VERSION_HEIGHTS=0,100,200 leo devnet
```

<Note>
  Custom consensus heights require the `test_network` feature in snarkOS.
</Note>

### Start with High Verbosity

```bash theme={null}
leo devnet --verbosity 3
```

Shows detailed debug logs from snarkOS.

## Using the Devnet

Once running, use the devnet with Leo commands:

### Deploy Programs

```bash theme={null}
leo deploy \
  --broadcast \
  --devnet \
  --endpoint http://localhost:3030 \
  --private-key APrivateKey1zkp8CZNn3yeCseEtxuVPbDCwSyhGW6yZKUYKfgXmcpoGPWH
```

### Execute Transactions

```bash theme={null}
leo execute main 1u32 2u32 \
  --broadcast \
  --devnet \
  --endpoint http://localhost:3030 \
  --private-key APrivateKey1zkp8CZNn3yeCseEtxuVPbDCwSyhGW6yZKUYKfgXmcpoGPWH
```

### Query Network State

```bash theme={null}
leo query block latest \
  --endpoint http://localhost:3030 \
  --network testnet
```

## Devnet Architecture

### Validators

* Validate and propose blocks
* Participate in consensus
* Maintain full ledger state
* Expose REST API

### Clients

* Broadcast transactions
* Query network state
* Do not participate in consensus

### Communication

```
Validator 0 ←→ Validator 1 ←→ Validator 2 ←→ Validator 3
     ↓              ↓              ↓              ↓
  Client 0 ←────→ Client 1
```

## Storage Structure

```
./
├── validator-0/
│   ├── ledger/          # Blockchain data
│   └── logs/            # Node logs
├── validator-1/
│   ├── ledger/
│   └── logs/
├── validator-2/
│   ├── ledger/
│   └── logs/
├── validator-3/
│   ├── ledger/
│   └── logs/
├── client-0/
│   └── logs/
└── client-1/
    └── logs/
```

## Default Private Keys

Devnet uses deterministic private keys:

```bash theme={null}
# Validator 0 (primary test key)
APrivateKey1zkp8CZNn3yeCseEtxuVPbDCwSyhGW6yZKUYKfgXmcpoGPWH

# Validator 1, 2, 3... (derived keys)
```

<Warning>
  These keys are for testing only. Never use devnet keys on mainnet.
</Warning>

## Monitoring the Devnet

### View Logs

```bash theme={null}
# Tail validator 0 logs
tail -f validator-0/logs/node.log

# View all validator logs
tail -f validator-*/logs/node.log
```

### Check Node Status

Query REST API:

```bash theme={null}
# Get latest block
curl http://localhost:3030/testnet/latest/block

# Get latest height
curl http://localhost:3030/testnet/latest/height

# Get node status  
curl http://localhost:3030/testnet/node/status
```

### View Metrics

If metrics are enabled:

```bash theme={null}
curl http://localhost:9000/metrics  # Validator 0
curl http://localhost:9001/metrics  # Validator 1
```

## Stopping the Devnet

Press `Ctrl+C` to stop all nodes:

```bash theme={null}
^C
🛑 Shutting down devnet...
   Stopped validator 0 (PID: 12345)
   Stopped validator 1 (PID: 12346)
   Stopped validator 2 (PID: 12347)
   Stopped validator 3 (PID: 12348)
   Stopped client 0 (PID: 12349)
   Stopped client 1 (PID: 12350)
✅ Devnet stopped.
```

## Troubleshooting

### Port Already in Use

```
Failed to start validator 0: Address already in use
```

Solutions:

1. Stop existing devnet
2. Use different ports: `--rest-port 4000`
3. Kill processes using the port

### snarkOS Not Found

```
snarkOS binary not found at path
```

Solutions:

1. Install snarkOS: `--install --snarkos ./bin/snarkos`
2. Provide correct path: `--snarkos /path/to/snarkos`

### Nodes Not Connecting

Check:

1. Firewall allows local connections
2. Port configuration is correct
3. Node logs for connection errors

### Storage Issues

```
Failed to initialize ledger
```

Solutions:

1. Clean storage: `--clean-only`
2. Use different directory: `--storage ./new-devnet`
3. Check disk space

## Performance Tips

1. **Reduce Nodes**: Use fewer validators for faster consensus
2. **SSD Storage**: Use SSD for `--storage` directory
3. **Lower Verbosity**: Use `--verbosity 0` for less logging
4. **Dedicated Storage**: Use separate disk for storage

## Comparison with Devnode

| Feature       | `leo devnet`                  | `leo devnode`          |
| ------------- | ----------------------------- | ---------------------- |
| **Nodes**     | Multiple validators + clients | Single node            |
| **Consensus** | Full BFT consensus            | Instant block creation |
| **Use Case**  | Realistic testing             | Rapid development      |
| **Speed**     | Slower (consensus)            | Faster (instant)       |
| **Resources** | Higher                        | Lower                  |

<Info>
  Use `leo devnet` for realistic testing and [`leo devnode`](/cli/devnode) for rapid iteration.
</Info>

## Next Steps

* [Deploy to devnet](/cli/deploy)
* [Execute on devnet](/cli/execute)
* [Use devnode](/cli/devnode)