Adobe Flex goes open source

Adobe is announcing the open source release of the Flex SDK. Included are all of the libraries and tools that are offered for free as part of the SDK. It's part of a continuing trend by Adobe to be more open and it's going to give developers access to the guts of Flex. This should mean better code, better components, and lots of good things for Flex developers and the Flex community.

Adobe Flex goes open source

Adobe is announcing tonight that the Flex SDK will be open sourced under the Mozilla public license, the same license that they open sourced the Action Script VM under (the Tamarin project). The move is just the latest in a trend of an increasingly open ecosystem around Flash and Flex which started with the Tamarin project.

The News Rundown

The Flex team has talked about open sourcing the project since its very beginning and did things like starting and giving people very early access to the betas of Flex 2. In chatting with them, it sounds like the impetus for this was just that the Flex community had grown large enough where a lot of exciting open source activity was happening, and they wanted to be involved. As part of the initiative, Adobe will be releasing the source to the following parts:

  • The Flex Compilers (mxmlc, compc, asc) - the command line tools that compile flex code
  • Flex command line debugger
  • View source utilities
  • Automated Testing Framework
  • Flex core component library - this includes Apollo components
  • Build Scripts
  • Web tier compilers
  • Flex-Ajax Bridge - already open source, but moving from MIT license to MPL License


Adobe will start by opening the Flex bug base in June and providing daily builds of Flex 3 at that time. Then between June and December, Flex 3 will be released under its current license. Shortly after this they will fully open source the SDK and open it up to external contributors. Adobe also has plans for a "second phase" in which people outside Adobe may be granted commit privileges to the core SDK and granted ownership over "sub projects" of the SDK. They would then be in charge of managing those projects. In chatting with David Wadhwani, the vice president of product development for Flex, he had this to say about how external community members can contribute code to the Flex SDK:

"Initially people will be able to contribute code by attaching it to a bug or enhancement request in the public bug database and we'll clearly state our development philosophies at this time. After a few months we'll start looking for external committers. We'll look for individuals who have been active contributors of high quality code that most closely maps to our development philosophies."

Developers Win

For Adobe and developers, this is really win-win. Adobe gets to leverage the community and ecosystem of open source, and the framework fits very well with an open source model. Developers can now actually contribute code and fixes to the framework and have those appear in the core distribution. One of the most exciting things for me is that some of the better custom components could, in theory, make it into the core release. This gives a lot of incentive for the people out there extending Flex by themselves, and gives developers using the framework the best components out there.

In talking to people, the general consensus seems to be quite good. Adobe is going to offer a commercial license for the companies who want support and warranty from Adobe, but there are no plans to branch the two code bases. As a result, the companies who want to have more openness in their technologies will be happy and those that still want Adobe to stand behind it can feel secure. I do wonder about the implication for OpenLaszlo, which has, until now, been able to carry the banner of open source in the Rich Internet Application community. I've also been hearing a lot of rumors about Microsoft having more open intentions behind Silverlight, so we may hear about that at MIX next week. Interesting times ahead. Adobe has set up a Google Groups for anyone that wants to discuss the news and project over at

More thoughts:

Ted Patrick
Ted Leung
Josh Tynjala
Robert Scoble (with video)
James Ward
Andrew Oliver
Mark Anders
Sho Kuwamoto
Ed Burnette
Jay Fortner (Read/WriteWeb)