Deploying Mentorship Backend flask app on Heroku

In this post, I will explain the steps I made to enable the Mentorship Backend app to run on Heroku.

Isabel Costa
Jun 27, 2020 · 5 min read

At Open Source we have a project called Mentorship System, which I started during Google Summer of Code 2018. This project is composed of several repositories: flutter, android, ios, and a backend written in Python (Flask).

I want to describe how I deployed the backend REST API project on Heroku, using its free tier.

Setup project to be deployable on Heroku ⚒️

So anitab-org/mentorship-backend already could be run locally using simply python command on a terminal and having the environment variables set.

However, I had to create a specific file and indicate the way I wanted to run the backend app on Heroku.

So to enable the project as it is to deploy on Heroku with a single click, just by connecting it with GitHub, I had to create a new file on the project called Procfile with this line, where application refers to the object that holds the flask app.

web: gunicorn run:application

I created this pull request (PR) #640 on anitab-org/mentorship-backend to add the changes mentioned above. With these changes, anyone that forks the project on GitHub can follow the same procedure as I did and deploy the project on Heroku.

Deploy on Heroku 🚀

Now that the project has everything that it needs to run on Heroku, let's create the configuration. In my personal account dashboard, I started by creating the app.

I clicked the “Create new app” option on my Dashboard

I gave it the name of the app, that will compose the Heroku app URL. In my case to get I named the app mentorship-backend-temp . I also had to select a region between United States and Europe.

“Create New App” view on Heroku

Then I clicked the “Connect with GitHub” option in the “Deployment method” section from the Deploy tab (which I was redirected to) and selected a repository on the “Connect to GitHub” section, such as my mentorship-backend fork repository. Because I am one of the admins of the anitab-org on GitHub, I ended up selecting is from the organization, instead of from my account.

At this point, with the app configured on Heroku and connected to GitHub, we are able to see the current deployments of the app on both platforms.

I set the Deployment method to GitHub
Deployment link is available at {repository}/deployments on GitHub

Next, I had to create the environment variables that the project needs to run properly and also connect with a remote database. This section is available in the “Settings” tab of the app view on Heroku.

Environment Variables Configuration section on Heroku

Then I made sure to deploy this app from the “Deploy” tab. As a result of this action, we have now the project deployed at:

In the end, I also enabled the Automatic Deploys feature. For that, I went to the page of the application on Heroku and went to the Deploy tab, and then enabled it. I could also enable Manual Deploy, which I used before, but since we are now paying close attention to what gets merged, I was confident in enabling it.

Automatic Deploys section on Deploy tab in Heroku app view

Now that the app is deployed, I can access the logs of this server, and debug if anyone experiences a bug specific to this running instance of the app. Although we can only see the most recent logs, it still comes in handy.

View logs of mentorship app on Heroku

Benefits for the community 👐🏾

Previously we were deploying this app in Amazon Web Services (AWS). However, we had some issues that made the app stop working there, in which we could not have access to the AWS environment to look at the logs, so as a temporary solution I decided to host the backend REST API on Heroku.

While we don’t have the app in production where we will potentially run the app on AWS, we can use Heroku to deploy the development version of the app. Although ever since I deployed to Heroku, I am amazed how this makes it easy to deploy the REST API and how anyone in the community can easily do this. Besides this, some weeks ago I discovered the Review App feature which allows us to easily deploy an app for any PR sent to our repository (with a limit of the number of apps since I’m using free tier).

I hope you enjoyed this blog post and learn about deploying apps into Heroku!

Interested in the project? You can reach us on GitHub on Zulip.

You can find me on GitHub, Twitter, LinkedIn, and my personal website. Open Source

Women transform technology. Technology transforms the world. Open Source

At, we envision a future where the people who imagine and build technology mirror the people and societies for whom they build it. We connect, inspire, and guide women in computing, and organizations that view technology innovation as a strategic imperative.

Isabel Costa

Written by

Software Developer / GSoC'18 Student with @AnitaB_org / Open Source enthusiast / Open Source

At, we envision a future where the people who imagine and build technology mirror the people and societies for whom they build it. We connect, inspire, and guide women in computing, and organizations that view technology innovation as a strategic imperative.

Medium is an open platform where 170 million readers come to find insightful and dynamic thinking. Here, expert and undiscovered voices alike dive into the heart of any topic and bring new ideas to the surface. Learn more

Follow the writers, publications, and topics that matter to you, and you’ll see them on your homepage and in your inbox. Explore

If you have a story to tell, knowledge to share, or a perspective to offer — welcome home. It’s easy and free to post your thinking on any topic. Write on Medium

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store