I'd like to implement a system that allows recognizing a user even after the app's cache and data have been cleared from the system settings, as X (Twitter) appears to do.

However, I can't figure out how this is possible.

In my case, I don't use any external login (no Google, Facebook, Apple, etc.), but I've noticed that app still recognize the user even after a complete data clearing, without requesting credentials again.

So I'm wondering:

• Where could the user's login or identification information be stored?
• Are there any Android memory areas or services (such as backup, device ID, or external storage) that can keep the session active?
• How could I implement a similar solution in a React Native app?

I was wondering if it uses Settings.Secure.ANDROID_ID as a unique device signature, and when opening an app, it sends a request to the server, checks its database, and allows access.

Do you think it can do this? Is this a secure method?

I'd like to implement a system that allows recognizing a user even after the app's cache and data have been cleared from the system settings, as X (Twitter) appears to do.

However, I can't figure out how this is possible.

In my case, I don't use any external login (no Google, Facebook, Apple, etc.), but I've noticed that app still recognizes the user even after a complete data clearing, without requesting credentials again.

So I'm wondering:

• Where could the user's login or identification information be stored?
• Are there any Android memory areas or services (such as backup, device ID, or external storage) that can keep the session active?
• How could I implement a similar solution in a React Native app?

I was wondering if it uses Settings.Secure.ANDROID_ID as a unique device signature, and when opening an app, it sends a request to the server, checks its database, and allows access.

Do you think it can do this? Is this a secure method?