DevTools, a suite of performance and profiling
tools that run in a browser.

Android Studio/IntelliJ, and VS Code
(enabled with the Flutter and Dart plugins)
support a built-in source-level debugger with
the ability to set breakpoints, step through code,
and examine values.

Flutter inspector, a widget inspector available
in DevTools, and also directly from Android Studio
and IntelliJ (enabled with the Flutter plugin).
The inspector allows you to examine a visual
representation of the widget tree, inspect
individual widgets and their property values,
enable the performance overlay, and more.

If you are looking for a way to use GDB to remotely debug the
Flutter engine running within an Android app process,
check out flutter_gdb.

DevTools

For debugging and profiling apps, DevTools might be
the first tool you reach for. DevTools runs in a
browser and supports a variety of features:

source-level debugger