Fly.io provides fast containerized hosting, that's perfect for Ruby on Rails apps. Combined with a SQLite database, you can even host 3 apps for free.
Fly.io is a platform for running applications globally. It's a great fit for Rails apps and it's free to get started since they provide a generous free tier. Their containerized apps will run on Firecracker VM's and the commandline tooling Fly provides works great. It's a breeze to deploy your app to their platform.
In this article, Fly.io describes how to launch a Rails app with SQLite in production.
The extensive step by step documentation, guides you from installing Litestack, to deploying the container in production. Just add your custom domain and your project is live.
Not to shabby, Fly allows you to run 3 (small) free apps simultaneously.
And if your application requires a database like PostgreSQL, you could always try another cloud hoster (ie. Aiven, ElephantSQL & Neon have free tiers).
