Deploying Your dApp Frontend to Heroku

Deploying Your App to Heroku

Earlier in the series, we deployed our Bounties.sol smart contract using Truffle, and added a react.js front end to interact with the contract through a web browser. In this tutorial we deploy our front-end application to Heroku.

This tutorial uses the source code from the tutorial, Truffle: Adding a frontend with react box. You have to add a Procfile to the project, but no other changes are required.


Heroku is a Platform-as-a-Service (PaaS) that enables developers to quickly build, deploy, and scale web applications. We use Heroku to deploy our application and make it publicly accessible.


You need to configure the application, as defined in an earlier tutorial, Truffle: Adding a frontend with react box.

Additionally, you need to install the Heroku CLI.

The Heroku CLI is available on Mac through Homebrew:

brew tap heroku/brew && brew install heroku

Also available through Snap for Linux:

sudo snap install --classic heroku

Heroku provides a graphical installer for Windows and Mac as well as ways of installing for various operating systems which you can find in the Heroku Dev Center.

Setup Heroku

Navigate to the project directory in your terminal as you need to need to run some git commands from the top level of the working tree. For the purposes of this tutorial, let's assume that you have an independent copy of the react project from the previous tutorial.

If you haven't already, initialize your project as a git repository. Heroku uses Git to update your code.

git init

Here we create a new Heroku app and indicate we want to use the create-react-app buildpack. This buildpack deploys the React UI as a static site.

heroku create --buildpack mars/create-react-app

Heroku automatically assigns your application a random name. Alternatively, you can give you application a memorable name accessible at

heroku create mynewdapp --buildpack mars/create-react-app

If you initialized the Git repository before running heroku create you are able to see the heroku remote by running git remote.

If you don't see a remote named 'remote', you can add it manually.

git remote add heroku [your heroku git remote url here]

Create a Procfile (Optional)

When using the create-react-app buildpack, you don't need to include a Procfile, but you can if you want to customize the app's processes. The implicit Procfile from the buildpack contains the following:

web: bin/boot

You can read more about Procfiles in the documentation.

Configure and Deploy the Smart Contract

Just like when configuring the web application to deploy locally, you need to deploy your smart contract. However, since the web application is now on a remote server, you won't be able to use a locally deployed smart contract.

You can follow any of the previous guides, for example the deployment as shown in Truffle: Adding a frontend with react box using Infura. You can use any public Ethereum blockchain, as long as you update the contract address in client/src/contracts/Bounties.json.

Deploy Your Application

You are now ready to deploy your front-end application. Heroku needs to ingest the contents of the /client directory. The current repository also includes source code for your smart contract, which Heroku does not know how to handle. Additionally, Heroku requires that your package.json file be in the root of the directory stored on the server.

Start by commiting your code locally, if you haven't already.

git add -A
git commit -m 'your commit message'

In order to avoid restructuring the application folders, you can instead just push the /client directory to the Heroku remote on the master branch.

`git push heroku `git subtree split --prefix client [branch (optional)]`:master --force`

Here we push the local repository to the remote called heroku, using the local branch programmatically defined using git subtree split --prefix client, to a remote branch called master, and force the push. You can get a better sense of what is happening by first running git subtree split --prefix client master. This returns a hash associated with the branch and directory you are pushing, for example 206ac9684c0e8e169121198ee6d1d19d0e4a06a7. You may specify a local branch to push. In this example, we used the branch called master but you can change that to any local branch.

This command only works once the master branch is established on the remote. If this is your first commit pushed to Heroku, run this instead.

git subtree push --prefix client heroku master

Note, you can use the second command exclusively, but occassionally draws issues when the Heroku remote gets out of sync with another remote (for example an origin remote on GitHub).

Note, if you are working out of the root directory of this series' code (if your .git file is in kauri-fullstack-dapp-tutorial-series instead of kauri-fullstack-dapp-tutorial-series/truffle-react-box-frontend), you have to push from the top level of your working tree. That is, navigate to the /kauri-fullstack-dapp-tutorial-series directory. From there, change the prefix to push only the code in /truffle-react-box-frontent/client.

`git push heroku `git subtree split --prefix kauri-fullstack-dapp-tutorial-series/client [branch (optional)]`:master --force`

Run the App

You should now see a URL to access your application. It should look like "". You can also run heroku open from the command line to open a browser to the appropriate url.

Once you navigate to the right webpage, you are able to configure metamask. Be sure to set MetaMask to use the right Ethereum network to interface with your deployed contract. Now you are able to interact with your smart contract through the browser anywhere with an internet connection.

Here's an example of the application running remotely in the browser.

Running Remotely