Heroku, Render, Fly.io, etc are a bit different than Hatchbox. They will provide you servers and deploy your application to them using containers.

Hatchbox works by configuring servers that you own. We will SSH into them and configure them for deploying applications.

First, you'll create a cluster of server(s). You can make a 1 server cluster, 2 servers, or 3+ servers. It's up to you. Each server gets told which parts of the application it's responsible for. For example, you might run a Rails app on 2 web servers and have a third server that runs PostgreSQL and Redis. You can configure them any way you would like.

We charge by the server, so you can use Hatchbox to save money by deploying multiple apps to the same cluster. For example, if you're consulting or have lots of side projects, you can create a cluster with a big server and deploy multiple applications to it. You'll only be charged for the single server instead of each application like you would with alternative hosting providers.

https://www.youtube.com/watch?v=BIgls9mxHTM