does kotlin coroutine suit for fire and forget scenario, for example, I want to fire 1000 network request in 5 minutes, something like

viewModelScope.launch{}

but don’t care about the result. When a coroutine is finished, does it goes away or it stays in memory?

It goes away.

viewModelScope is not good for that - it could be canceled

Depends on required lifecycle of those requests. Launch and forget doesn't mean that request doesn't have lifecycle and may be cancelled

It has the lifecycle equal to Application’s lifecycle. And I will create my own coroutine scope for that

GlobalScope is also fine for this