PolyLingual is a new Flutter package that provides internationalisation (multi-language) capabilities for a Flutter app. It does this using a simple JSON file that is embedded into the app.
This JSON file can then be updated as required without needing an app rebuild. This is useful for correcting string errors, updating messages or even adding new languages to an app without requiring a rebuilt.
As well as being used for internationalising a Flutter app, PolyLingual could also be used for the maintenance and update of strings for a single language within an app.
More details can be found here