Adobe have announced tonight, via Robert Scoble and the ScobleShow that they are opening up the Flex platform under a Mozilla Public License (an Open Source license). Flex is a group of technologies (much similar to .NET or J2EE etc.) that provides a more programmer-friendly development environment for Flash, rather than a graphics-driven environment that Flash was associated with.

Previously the source code to the ActionScript components in the Flash SDK were available, and from tonights release Adobe will also open source other components of the SDK such as the compiler, debugger (written in Java) and the class libraries. When compared to other development platforms, Flash/Flex has always been more closed and controlled than other alternatives, while a few open source projects have attempted to reverse engineer parts of it (although the server components aren’t being opened up). The schedule is that the development community and all code will be available by the end of the year, and while having code is great, the better part is that Adobe will be putting all their weight behind the open source projects with developers, support etc. (something you might expect them to do).

This announcement can be taken out of context, and it is important to understand that Adobe are opening up tools that help developers build applications – the runtime will remain closed (Flash itself). I actually can’t imagine a platform being able to survive *without* all the developer tools and class libraries being completely open, and perhaps this is what has spurred Adobe to open up Flex. If you look at other popular development platforms such as even Win32, the analogous tools to Flex have usually always been open or at least accessible, as it greatly assists developers.

Adobe are opening up part of their ecosystem, which is great, but don’t hold your breath for an open source Flash runtime anytime soon (unlike Java). If you are a Flex developer, this is great news for you, as you will now be able to dig a bit deeper and contribute to the tools such as the compiler and debugger – but this announcement will definitely be met with calls of ‘not enough’ from the open source community and those waiting for a fully open and cross platform rich application platform from Adobe.