I am building a flutter application and I want to use a stateful widget in my project and want to use the getx library for state management. I was wondering if there is going to be any performance
No performance issues at all. Preferring using stateful widgets with pages using textformfield even it have GetX.
Update : Don't use GetX for overall production-level projects. I clearly not recommending the package as it is been made issues over production, but you can use for minimizing code in some parts, Navigation or in your personal projects.
Refer the Reddit discussion to know more cons about GetX.