You can use heroku, but as your app grows in complexity, (say static javascript frontend, backend, queue, and maybe a few AWS or GCP native services) you have to stitch something together with heroku + vercel + ?? + can't use RDS, but wish i could. :)

Heroku review apps are analogous to our ephemeral environments, but we can deal with much more complicated environments, which reduces complexity in your CI/CD platform, production deployments or on-premise deployments if needed.