Back-End Type: Serverless
Whenever possible, I prefer serverless functions (yes, serveless is a silly term) over regular servers. I think you should only pay for what you use, and I like knowing that my service would automatically scale to handle a peak of traffic without worrying about server resources. I am not a fan of writing provider-specific code in my app, but it is quite minimal with Vercel, and switching to a different provider would be fairly easy. I am open to other paradigms (such as Google Cloud Run) as long as it's free for no traffic, and scales automatically.Might change soon? Possibly
I am mainly keeping an eye on PaaS alternatives, because I prefer not having to deal with infrastructure. I've been using Heroku for many years for non-serverless projects and I am still quite happy with it, although it has been quite stagnant over the years. There is also Render, Fly, Google App Engine, AWS Elastic Beanstalk, and probably many more.
For those who like to dive into infrastructure, there are Docker-based hosting and IaaS (AWS, Google Cloud, Azure). I am also interested in trying "serverless Docker apps" like Google Cloud Run or AWS Fargate / ECS.