Here is a list of some tools beyond the included debugging IDEs FlashCS3 and Flex2 that are helpful to making your Flex or Flash projects more bulletproof.
Reflexutil allows Adobe Flex developers to debug and alter properties of components while running an application.
Flex-Spy allow you to inspect and dynamically change most properties and styles of the visual components in your Flex application.
XMLObjectOutput is a really cool tool for debugging when you are writing Flex Apps. It is somewhat similar to CFDump and displays the structure of any Object in Flex.
This extension comes with all the currently published flash player plugins (from the version 2 to the most recent 9,0,16) and allows you to easily switch from one plugin to another, or also to remove the currently installed plugin (maybe for testing the express install).
For real-time debugging and spying on your code. It is 16KB for the connector that you add to your files but it is debugging in style. If you have any issues with a live app or to help during testing Xray is great. It also includes a nifty admin site that allows you to access objects and spy on your code at any time.
Xray (The AdminTool) is a “snapshot viewer” of the current state of your Flash application without impacting the performance or the file size of your application. Xray’s true nature is to look into the very guts of the Flash application and disolve the 2d myth you see on screen to a 3D tangible entity you can truly crawl through.
Alcon (ActionScript Logging Console) is a lightweight debugging tool for ActionScript 2.0/3.0 developers that provide a way to output debugging information (traces) from the debugged application to an external output panel.
Multiple output levels (LOG, DEBUG, INFO, WARN, ERROR, FATAL)
Inspection for Object and MovieClip types
Multiple output targets using Publishers (similar to log4j)
Flash 6 & 7 compatible. Flex is also supported.
Small filesize, about 3kb with all available publishers.
GUI Console for viewing and inspecting log messages.
DebugIt is a two-piece debugging tool designed to help developer debug Flash applications and content outside of the Flash authoring environment. Displays traced data in a seperate SWF so you can debug outside of Flash, while running your application in its shell/production environment.
Brings PHP‘s “print_r” to Flash, invaluable once you start to use it. Free, Complete Source Available.
JAVA application which displays traced data from SWF and other (PHP,Java…). It is created for retrieving xml log data from Flash Swf aplications which are using XmlSocketConnection.Could be a command line or windowed application.
It is a firefox add on that displays trace() output in a sidebar window.While running any .swf Flash file in your browser you can see all the output generated by the "trace" flash functions in this sidebar component.