Nearby Connections enables advertising, discovery, and connections between nearby devices in a fully-offline peer-to-peer manner. Connections between devices are high-bandwidth, low-latency, and fully encrypted to enable fast, secure data transfers.

https://pub.dev/packages/flutter_nearby_connections

special thanks to this repo. which I have used as a base to start developing my chat app. https://github.com/VNAPNIC/flutter_nearby_connections

This chat application is a mobile app. that is developed using flutter/dart to allow devices(android/iPhone) to connect with each other using the nearby connection in an offline mode by advertising and browsing, once the connection is established, users start to make a conversion with each other by sending text messages then disconnect after they finish.

You can find more Info in detailed about how is working https://developers.google.com/nearby/connections/overview

1. Regarding to android, you need real devices for testing, unlike IOS can be done using simulators.
2. Dont forget to enable nearby which will by default turn on (wifi,bluetooth and location) before start.
3. This is the first version that contains the basic features of chat like sending a text message, not attachments or audio voice, It can be improved later on.