Introducing Ethermint — Part 1

As you might have heard, the Tendermint consensus engine can support almost any other crypto-currency, as long as the source code is open-source and some developer is willing to write an ABCI wrapper around it.

As part of Tendermint’s goal to launch the COSMOS hub, we are enabling Ethereum to run on top of Tendermint. This allows developers to have all the nice features of Ethereum, while at the same time benefit from Tendermint’s proof of stake implementation. Tendermint combined with Ethereum results in fast block times, transaction finality while also getting the goodies of smart contracts.


Depending on how cutting edge you would like to be, you can choose between the develop branch or the master branch. Currently you have to choose the unstable branch for Ethermint.

Install go1.8

To explore the possibilities of Ethermint you need a couple of prerequisites. First, you need to have go1.8 installed and your $GOPATH properly configured. This is necessary since we are currently not shipping binaries for Ethermint.

Install Tendermint

The second requirement is that you are able to run a Tendermint node, since this engine handles all the blockchain aspects, like P2P and consensus. To install Tendermint just run “go get -u” and you should be good to go. If not follow this link. As an alternative you can also download binaries.

Install Ethermint

Lastly, we need to install ethermint itself. First clone the source code “git clone” . Afterwards, switch into the source code directory and run make install and voila, Ethermint should be installed.

Install geth

Geth is an Ethereum tool that allows you to attach to a running Ethereum node over RPC. We will use it later to interact with Ethermint. Please follow this guide to install it on your local machine.

Running Ethermint

Starting Tendermint

First you need to initialise Tendermint by running “tendermint — home ~/.ethermint/tendermint init”. This initialises the Tendermint node. The next step is to run “tendermint — home ~/.ethermint/tendermint node” to start the Tendermint node.

Starting Ethermint

In a second terminal window switch into the folder with the Ethermint source code. Then run “ethermint — datadir ~/.ethermint init dev/genesis.json” to initialise the Ethermint files. Afterwards, start the Ethermint node by running “ethermint — datadir ~/.ethermint — rpc — rpcaddr= ws — wsaddr= — rpcapi eth,net,web3,personal,admin”.

This tells Ethermint to expose a lot of its functionality over RPC.

At this stage you should see blocks streaming by in both the Tendermint and the Ethermint windows.

Attaching geth to Ethermint

In a third terminal window run “geth attach http://localhost:8545". Now you should find yourself in a console environment, where you can use the Web3 commands to interact with the Ethermint node.


In this short introduction I have explained how to setup Ethermint and how to interact with it using geth. From here, you should be able to develop smart contract applications or simply send transaction between different accounts.

If you have any trouble setting up any of the above systems or are running into issues using them, please find me on slack under @adrian_brink on twitter or via email at .

Next Up

In my next blog post I will explain how to use docker to setup multiple Ethermint instances, so that you can experiment with running networks of Ethermint nodes. Furthermore, I will explain how Ethermint relates to the COSMOS hub.