Detailed consequences of using a Custom Server

[tobiaspickel]

Summary

Hi, there we are currently evaluating implementing a custom server but I do find the docs a bit fuzzy.

A custom server will remove important performance optimizations, like [Automatic Static Optimization](https://nextjs.org/docs/pages/building-your-application/rendering/automatic-static-optimization).

It states that it will remove important performance optimizations.
I'd like to know what the consequences are in detail.
We will be using the app router so optimizations in pages router do not really affect us.
But I'd like to know what issues may pop up 😓.

Additional information

No response

Example

https://nextjs.org/docs/app/guides/custom-server

[icyJoseph]

I think this is good enough to open a documentation issue. I'll try to create an issue from the discussion. With this it'd be 3 items I want to tackle on custom servers - so I can put it higher on my stack of TODOs