I am developing mobile app using react native. I am using Amazon AWS as back-end.

My question is how do I restrict users to a particular country? That is, I want people from only one country may use my mobile app.

I have released my app on google play store and there I have made a selection to make my app available in a particular country. But I want to be more strict. I want to have some more checks maybe in my client code or back-end AWS server code where I can check for country.

For more information, I am using the following Amazon AWS services for my mobile app: AWS S3, AWS lambda etc. Is there some code that I can write here using which I can restrict mobile users to a particular country? What are other elegant ways?