I don't find this to be true at all.
> you need an external server
Spoiler, you need an external server for everything on the web; you've just been brainwashed to think serverless is actually that.
> you need an external server
Spoiler, you need an external server for everything on the web; you've just been brainwashed to think serverless is actually that.
Lots of languages and frameworks make it easy to be self-hosted with there own server. In Python, .net, Go, Rust this is quite common.
This means that your app can be a self-contained app + server and the server part can have some business logic as well.
With Go, .net, Rust apps (and potentially others) that's quite nice to be able to produce a single binary app that you can just run anywhere without installing any framework or setting up any external server and it's ready to listen to incoming queries.
That can even be a good enough setup for home things that are not exposed to the web and where setting up reverse proxies could be overkill.
So yeah, you technically don't need one for Ruby or Node.js, but I sure would.