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Start Besu

Use the besu command with the required command line options to start a node.


Besu installed

Local block data

When connecting to a network other than the network previously connected to, you must either delete the local block data or use the --data-path option to specify a different data directory.

To delete the local block data, delete the database directory in the besu/build/distribution/besu-<version> directory.

Genesis configuration

To define a genesis configuration, create a genesis file (for example, genesis.json) and specify the file using the --genesis-file option.

When you specify --network=dev, Besu uses the development mode genesis configuration with a fixed low difficulty. A node started with --network=dev has an empty bootnodes list by default.

Predefined genesis configurations for named networks are in the Besu source files.

Confirm node is running

If you started Besu with the --rpc-http-enabled option, use cURL to call JSON-RPC API methods to confirm the node is running.

  • eth_chainId returns the chain ID of the network.

    curl -X POST --data '{"jsonrpc":"2.0","method":"eth_chainId","params":[],"id":1}' localhost:8545
  • eth_syncing returns the starting, current, and highest block.

    curl -X POST --data '{"jsonrpc":"2.0","method":"eth_syncing","params":[],"id":1}' localhost:8545

    For example, after connecting to Mainnet, eth_syncing will return something similar to:

    "jsonrpc": "2.0",
    "id": 1,
    "result": {
    "startingBlock": "0x0",
    "currentBlock": "0x2d0",
    "highestBlock": "0x66c0"

Run a node for testing

To run a node that mines blocks at a rate suitable for testing purposes:

besu --network=dev --miner-enabled --miner-coinbase=0xfe3b557e8fb62b89f4916b721be55ceb828dbd73 --rpc-http-cors-origins="all" --host-allowlist="*" --rpc-ws-enabled --rpc-http-enabled --data-path=/tmp/tmpDatdir

You can also use the following configuration file on the command line to start a node with the same options as above:


The following settings are a security risk in production environments:

Run a node on a private network

To run a node on your private network specifying a genesis file and data directory:

besu --genesis-file=<path>/genesis.json --data-path=<data-path> --rpc-http-enabled --bootnodes=<bootnodes>

Where <data-path> is the path to the directory to save the chain data to. Ensure you configure a peer discovery method, such as bootnodes.


You might need to set --tx-pool-limit-by-account-percentage to 1. The default value is suitable for Mainnet, but may cause issues on private networks.