Configuration

Anvil-Arbitrum provides flexible configuration options to tailor the local testing environment to your specific needs. You can configure the node using a JSON file or environment variables, which can also be combined with CLI flags.

Configuration File

For complex or frequently used setups, a JSON configuration file is the most convenient method.

1. Create a config.json file

Create a file named config.json with the desired settings. The structure should match the fields in ArbitrumConfig.

{
  "chain_id": 421614,
  "arb_os_version": 21,
  "l1_base_fee": 15000000000,
  "gas_price_components": {
    "l2_base_fee": 800000000,
    "l1_calldata_cost": 16,
    "l1_storage_cost": 0,
    "congestion_fee": 0
  },
  "tx7e_enabled": true,
  "mock_l1_bridge": "0x0000000000000000000000000000000000000064"
}

2. Load the Configuration

Use the --gas-config CLI flag to specify the path to your configuration file when starting the node.

anvil --arbitrum --gas-config config.json

Note: CLI flags override any settings defined in the JSON file. For instance, if you set chain_id in config.json but also provide --arb-chain-id 42161 on the command line, the value 42161 will be used.

Environment Variables

You can also configure Anvil-Arbitrum using environment variables. This is especially useful for CI/CD environments or for making temporary adjustments without modifying files.

The following environment variables are supported:

Example

export ANVIL_ARBITRUM_CHAIN_ID=421614
export ANVIL_ARBITRUM_L1_BASE_FEE=15000000000

anvil --arbitrum

This will start Anvil-Arbitrum with:

• Chain ID: 421614
• L1 base fee: 15 gwei

Order of Precedence

The configuration is applied in the following order — with later sources overriding earlier ones:

1. Default Values: Hardcoded defaults in the application.
2. Configuration File: Values from the JSON file loaded via --gas-config.
3. Environment Variables: Values set in the environment.
4. CLI Flags: Arguments passed directly on the command line.