Setting app restrictions in Google Credentials for an Ionic app

Hey, I have almost finished developing an Ionic app and I am using some Google API keys. I want to restrict the apps that can use the APIs but I don’t know how to set the restrictions for an Ionic app, since I don’t know if it sends requests from an IP address in each user’s phone or if it works like a URL. I already tried choosing the Android app option with the package name and the SHA1 signature but it didn’t work. Any ideas on how to secure the key?