AsyncStorage

AsyncStorage is an unencrypted, asynchronous, persistent, key-value storage system for React Native applications.

AsyncStorage handles local data persistence for React Native apps on Android, iOS, and macOS. It functions as a global key-value store: strings go in, strings come out. Developers use the @react-native-async-storage/async-storage package to manage user preferences or session tokens without blocking the main UI thread. On Android, it leverages SQLite or RocksDB (depending on availability); on iOS, it stores small values in serialized dictionaries and larger ones in separate files. Performance remains stable for simple datasets: keep individual entries under 2MB to ensure optimal read and write speeds.

https://react-native-async-storage.github.io/async-storage/