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Ethereum Harmony

Ethereum network private peer. Based on EthereumJ implementation.

Ethereum Harmony Demo

Smart contract trace sample:


  • Ethereum peer JSON-RPC 2.0 standard ;

  • Keeping private keys in filesystem keystore compatible with go-ethereum;

  • In Browser command line terminal;

  • Blockchain canonical tracing;

  • Monitoring peers connectivity;

  • Easy go Ethereum wallet;

  • Full trace of contract storage locally;


Prerequisites Installed:

  • Java 8 (64 bit)



  • git clone
  • cd ethereum-harmony
  • Run Service: gradlew runMain ( live network by default or any other environment )

Navigate to web view http://localhost:8080 JSON-RPC is available at either http://localhost:8545/rpc or http://localhost:8545

In order to provide ability to disable unneeded features, any of app modules could be disabled: web, contracts, rpc. Check configuration for more info.

Run RPC only: gradlew runMain -PrpcOnly

(*) Use gradlew runMain -Dserver.port=9999 option to change web interface port number.


Command line options

Environment Run ...
Main gradlew runMain Start server connecting to Main network
Ropsten gradlew runRopsten Start server connecting to Ropsten network
Classic gradlew runClassic Start server connecting to Ethereum Classic network
Private gradlew runPrivate Start server, no network connection, single miner running
Custom gradlew runCustom Start server connecting to custom network (check custom network)


Run in a custom network

  • git clone
  • cd ethereum-harmony
  • Run Service with custom config:
gradlew runCustom -Dethereumj.conf.file=/path/to/custom.conf
  • It is also possible to use CLI to pass parameters:
gradlew runCustom -Dpeer.networkId=10101 -DgenesisFile=/path/to/custom/genesis.json -Dpeer.discovery.enabled=false

Note: parameters that haven't been substituted by either custom config or CLI will be supplied from ethereumj.conf

Custom config file format

Format of the file should be the same as of ethereumj.conf. It also works to specify only necessary config parameters.

An example:

genesisFile = /path/to/custom/genesis.json
database.dir = database-private

peer {
  networkId = 10101
  listen.port = 50505

  discovery.enabled = false
  active = [
    {url = "enode://6ce05930c72abc632c58e2e4324f7c7ea478cec0ed4fa2528982cf34483094e9cbc9216e7aa349691242576d552a2a56aaeae426c5303ded677ce455ba1acd9d@"}
    {url = "enode://20c9ad97c081d63397d7b685a412227a40e23c8bdc6688c6f37e97cfbc22d2b4d1db1510d8f61e6a8866ad7f0e17c02b14182d37ea7c3c8b9c2683aeb6b733a1@"}
} = false

If you run Harmony without using Gradle, add -Dethereumj.conf.res=harmony.conf to command line, so Harmony properties will be applied to system context too.
If you use some custom resource file as config, just add -Dethereumj.conf.res=harmony.conf,custom.conf to java exec command so both will be applied.





Check Development troubleshooting

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📜 ... License GPL 3.0