In Flutter, hot reload and hot restart are two different mechanisms for updating the application during the development process.

Hot Reload :

* Hot reload is a feature that allows developers to update the source code of their app while it's running, without having to restart the app or lose its current state.

* With hot reload, changes made to the code are injected directly into the running Dart Virtual Machine (VM), and the widget tree is rebuilt with the new code.

* Hot reload preserves the state of the app, so you can see the effects of the changes you made immediately, without losing your current position in the app.

* Hot reload is a quick and efficient way to experiment with small changes and see the results instantly. Hot Restart :

* Hot restart is a feature that completely restarts the app from scratch, and reinitializes the Dart VM and the Flutter framework.

* With hot restart, changes made to the code are compiled and linked from scratch, and the widget tree is completely rebuilt.

* Hot restart does not preserve the state of the app, so any unsaved changes or user inputs are lost when the app restarts.

* Hot restart is useful when you want to test major changes or when the app has crashed and needs to be restarted.