Updated 2019-10-01

Creating Hyperledger Besu Genesis File

The genesis file defines the first block in the chain and the first block defines which chain you want to join.

For Ethereum MainNet and public testnets (for example, Rinkeby), the genesis configuration is defined in Besu and used when a public network is specified using the --network command line option.

For private networks, create a JSON genesis file and specify the genesis file using the --genesis-file command line option.

Network wide settings are specified in the genesis file so all nodes in a network must use the same genesis file.


  "config": {
    "chainId": 2018,
    "constantinoplefixblock": 0,
    "ibft2": {
      "blockperiodseconds": 5,
      "epochlength": 30000,
      "requesttimeoutseconds": 10
  "nonce": "0x0",
  "timestamp": "0x58ee40ba",
  "extraData": "0xf83ea00000000000000000000000000000000000000000000000000000000000000000d5949811ebc35d7b06b3fa8dc5809a1f9c52751e1deb808400000000c0",
  "gasLimit": "0x1fffffffffffff",
  "difficulty": "0x1",
  "mixHash": "0x63746963616c2062797a616e74696e65206661756c7420746f6c6572616e6365",
  "coinbase": "0x0000000000000000000000000000000000000000",
  "alloc": {
    "9811ebc35d7b06b3fa8dc5809a1f9c52751e1deb": {
      "balance": "0xad78ebc5ac6200000"