Who Should Read This Document

This doc is for developers, and it aims to show how they can join the Extdev Testnet and deploy their smart contracts. If you are looking for information on how to run nodes or to become a validator, please checkout our Validator Guide.


Deploying to Extdev is no different from deploying to Ethereum mainnet, or to Rinkeby. If you know how to do one, you also know how to do the other.

Loom Network uses Truffle to build, test, and deploy our smart contracts. To make our life easier, we developed something called a provider that lets Truffle deploy to Extdev just like it deploys to Ethereum.

Without delving too much into details, the provider works like a bridge that makes Web3.js calls compatible with Extdev.

This document shows how you can use Truffle and the Loom Truffle Provider to build a simple Web UI that interacts with Extdev.


Make sure the following requirements are met and then follow the steps in the next section:

Node >= 8
yarn or npm

Setting Things Up

First, let's clone the Truffle DAppChainExample repository. Open a terminal, cd into the directory where you store your projects, and run the following command:

git clone https://github.com/loomnetwork/truffle-dappchain-example

Next, cd into truffle-dappchain-example:

cd truffle-dappchain-example

and run:

yarn install

Run against Extdev Testnet

Generate the Loom private key

The following command will download the loom binary and generate the private key for you:

yarn gen:extdev-key

The Loom private key will be saved into a file called extdev_private_key.

Deploy to Extdev Testnet

As an example, we will deploy and run our application against Extdev Testnet.

Run the following command:

yarn deploy:extdev

The above command will compile and then deploy our smart contract to the Extdev Testnet.


Run this command below to send transactions to the smart contract deployed to Extdev Testnet:

yarn test:extdev

If everything looks good, let's spin up a web server and interact with our smart contract.

Start the Web Interface

The web interface is built with React and Webpack. Open a new terminal and run the following command:

yarn serve:extdev

The web interface is available on http://localhost:8080.

Useful information

  1. In order to correctly redeploy the contracts, there's a command yarn deploy:reset.

  2. Also, is possible to call truffle directly with yarn truffle.

  3. We're not versioning the build directory for this particular example, although is recommended to do so. The limitation can be removed by editing the .gitignore file.