Laszlo Vs Flex

October 06, 2004

Now that Laszlo is open source and Flex has a free Non-Commercial License it is safe to assume that we will be seeing increased interest in server side swf generation.

My question, and I'm sure many other people have this question is - Now that Laszlo is free (but you can still purchase support), what can Flex do that Laszlo can't? And also what can Laszlo do that Flex cannot?

The closest thing I found to a comparison is this forum thread on Laszlo's site. But it was posted while Flex was in Beta, so not much was said about flex - its also probably a bit Laszlo biased.

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6 people found this page useful, what do you think?


I've seen posts all over the net about the Flex Non-Commercial license but they leave out the key factor for most developers is that it is a Non-Commercial/Non-Institutional license and the Non-Institutional part is still the biggest sticking point for most working on real world apps. Most of our clients are small to medium size educational institutions with the rest being small to medium size businesses so that new licensing is still worthless for those of us creating apps used in those situations. These types of institutions and businesses can't justify or afford an additional $12,000 on top of the development costs so Flex is a non-option. Laszlo has now be renewed as a focus of RIA development for those of us in the small to medium sized world.
Price is one thing, but to me the thing that makes Laszlo a more viable solution is that Laszlo will run on versions of Flash down to version 5. Flex requires Flash 7. This eliminates a large user pool, and therefore makes Flex a viable solution for intranets only where the Flash version can be controlled. For a public facing site, I would not use a solution that is not useable by even 5% of visitors. On the down side for Laszlo... no support for Unicode ( due to the Flash 5 requirement I think. )
The only downside I see w/ using Laszlo is that it doesn't run on JRUN4.
Laslzo VS. Flex hmmm.... This question has been keeping me up at night! I think that Flex has some major advantages in performace and development environment. I have been in J2EE development for years now and I like how Macromedia has adopted "TagLibs" this makes integration much easier. Laszlo on the other hand is open-source so it seems to be a great place to start for small businesses looking to start developing RIA's. This debate will be won by creating an "OPEN" standard for RIA's that run on any J2EE server without expensive plugins. For now I think I'm going to stick with Laszlo simply because of the cost factor.
Google's gmail made javascript xmlhttprequest object and other interface goodies into a cool app, CF should copy this while staying with flex as language to make this kind of interface.
You can run Laszlo on JRun, though its not officially supported. No one has mentioned using plain old Flash 8 (or MX or MX 2004) from RIA. Not that I could really blame you. Laszlo compared to Flash 8 for RIA -- Laszlo by a mile.
Flash 8 has been wonderful to work with. I've recently upgraded I believe it's one of the best releases by Macromedia to date. One have to wonder about the future of Flash since the Adobe acquisition. However, this new release has proven to be a tremendous improvement on the existing platform.
Flash 8 does something Laszlo doesn't and it's got me stumped trying to find a work-around. FlashType ... an awesome font rendering engine is only available in 8 and compared to Laszlo's font rendering, well there is no comparison! I need to build a text-viewer that has flash 8-type advanced anti-aliasing & font rendering but I need it to have an RIA back-end like Flex or Laszlo. I don't have the budget or the stomach for the co$t of the Flex server. But Laszlo stops at Flash 7! Does anyone have a suggestion for combining the Laszlo architecture with a Flash 8 text -viewing widget? Or a better solution for rendering fonts?
Laszlo didn't stop at Flash 7! OpenLaszlo3.1 allows compilation to SWF8, and you can call any Flash AS interface in your LZX code. Note that using Flash-specific APIs in your Laszlo app makes your code non-portable so it may not work on all runtimes. You should propose a fix and then contribute to the OpenLaszlo platform!
Hello, I think you need to look into openlaszlo which is better than flex 2.0 You can create google maps via flash and ajax based on it, it?s better than Flex and for free since it?s an open source ;) You can with openlaszlo to make flash and ajax output, so you code it for once, and you can have any output you want. Multiple runtimes has always been on the roadmap. LZX was conceived as a language that would be independent of Flash. This is being proven out with the implementation of the AJAX/DHTML runtime. Finally they signed up with sun to support Mobiles as well. Sun Microsystems Inc. the creator and leading advocate of Java? technology, and Laszlo Systems, Inc., the original developer of OpenLaszlo, a leading open source rich Internet development platform, today announced a collaboration to enable OpenLaszlo applications to run on devices supporting the Java? Platform, Micro Edition (Java ME) application. With this move, Sun and Laszlo are actively contributing resources to a new project for the OpenLaszlo community, code-named Orbit. So I think Flash with OpenLaszlo is much better than using flex or ajax. See Yahoo and Google Maps here by OpenLaszlo Yahoo Map demo: sources is in same directory: As for google Maps in Flash check it here ;) Google Maps demo: sources : (SVN of google code) So I guess OpenLaszlo is the way to go ;)
I think OpenLaszlo's syntax is cleaner.
The one advantage I see to OpenLaszlo is it's ability to compile into SWF files OR DHTML. However, the component base and developer community is much larger for Flex. The new FlexLib( provides some excellent additions that seem to be lacking in Laszlo. For example, check out the fire and cloud creation components. Flex seems to have Laszlo beat on the graphics/animation side.
Hello, I (and my coworkers) have quickly jumped onto the OpenLaszlo bandwagon. We find that it is a great fit for what we are trying to do. However, one of our concerns has been how to display/manipulate a Google Map (or possibly Yahoo Map) within an OpenLaszlo application. Today, I came across this thread and tried out the samples found at, as posted above. But it doesn't seem to work simply out-of-the-box. (And all I can do is download the files from the site.) I also tried the following link, but the page is just empty. Can anyone point me to an explanation of how to use the files? Thanks.
I wonder whether multiscribe might help for rendering unicode. It can cope with complex sctipts but I don't know how it compares to Flash Type. A little more information is available from
Hi guys, have you tried to make a reasonably large size of application with laszlo. I tried and the xml based laszlo language is simply not a programming language. I am scared the project getting unmanageable..
Hi, well, I tried both and I must admit that I will stick with Flex, although I am a huge open-source lover and usually build all my projects with open source software. Admitted, the possibility of OpenLaszlo to compile to both DHTML and Flash is simply awesome. But on the other hand, Flex has some major advantages that justify paying the 500 bucks for the FlexBuilder (and, no, for most projects you do *not* need the Data Service components which are really costly). First, FlexBuilder is simply a great IDE. I did not find something similar for Flex, and a layout that would take me hours to build in Laszlo is done with FlexBuilder in a couple of minutes (I exaggerate a bit). Second: Skinning. Skinning Flex is so easy, I would say that 80% can be done by CSS without the need to create any icons, graphics etc. Plus, there are so many ready-made skins you just need to download, Mac-style, Vista-style, you name it. Third: Component market. I found so many really awesome components for Flex, whereas there are really few for Laszlo. So, no need to roll your own, a huge time-saver. Fourth: Features, Stability and Performance. I implemented a proof-of-concept of an application both in Flex and in Laszlo, and the resulting swf was *way* faster when built with Flex. The app was really simplistic: a window + a grid component which displayed a list of users. Plus, there are a couple of features not supported by Laszlo which work out of the box with Flex. I remember fighting with double click events on a grid component in Laszlo. Doable, but only with workarounds. One negative aspect of Flex: Flex uses ActionScript as the language of choice, so you definitely need to learn AS3. To sum it up, I think both development speed and runtime performance are far better with Flex than with Laszlo, although also Flex has its drawbacks, bugs etc. Component market and user base is vivid for Flex, plus customization is easy. Good IDE, worth paying the money for it.
Thanks for the detailed write-up Hans. Full disclosure: I work for Laszlo Systems, which is the corporate sponsor of the OpenLaszlo platform. There are a couple of points you made that I wanted to address: You mentioned that the simplistic Flex application you made performed substantially faster than the OpenLaszlo one. My experience is that comparable real-world OpenLaszlo applications perform about the same as their Flex counterparts, in application size, startup time, and runtime performance. A simplistic app may highlight issues that do not become apparent as the application increases in complexity. I'd like to see the OpenLaszlo application you built; it's possible that there's a simple fix that would make it perform equally - or even better ;). You'll find a lot of highly complex, publicly-deployed OpenLaszlo applications at the URL below, and I'm sure that you'll find that they perform quite well: Regarding the double-click handling, I think I know exactly what you're referring to, because I filed this bug on it some time ago: If you look at the history of the bug, you'll notice that we received a contributed fix that addressed the issue, and that we tried to integrate it, but ran into issues doing so. Those issues were never addressed by the contributor, which is why you had difficulty listening for the ondblclick event of grid. Note that I'm not trying to blame anything on the contributor in this case; we are always grateful to developers who wish to help with the OpenLaszlo project. Instead, I'd like to point out that open source software - which you professed to love in your opening paragraph - is often dependant on the voluntary contributions of willing developers. This is a fact-of-life of open source software. It may even be a testament to the power of OpenLaszlo that you were able to work around the double click issue. Do you see yourself being able to apply a similar workaround to a missing feature of the Flex grid?
I have only used open laszlo (never flex) and I did this for several reasons. One and most important is that open laszlo is free (flex just had become free). However, finding documentation on open laszlo is very difficult, outside what they have. The font is great in open lazlo. I would never use Flash to develop just because of the terrible fonts I have had problems with. AS is an absolute short, it sucks. As for open laszlo being only to go back to Flash 7, who cares. The player is free. As far as I am concerned, if they can not run Flash 9, time to upgrade to a new computer.
I like openlaszlo but one thing - in many cases old code does not work in new opelaszlo versions. It's not a problem if you have small project but how about for something heavy? Openlaszlo guys always change rules. Even dynamic class creation was changed from version 4.1. For old versions it was "new LzView()" and now "new lz.LzView()" So it's very risky to create big projects with openlaszlo ...
Alex - there are sometimes changes that happen with new releases. There is a script provided to help with migration. I think its a problem all-around -- moving between Flash versions is not always a picnic either in my experience. (I used to work for Macromedia, now I work for Laszlo. I've seen similar issues in every developer platform I've worked with including writing native code with OS libraries and frameworks.) General comments: From a performance perspective, it is true that OpenLaszlo used to be slower than Flex, but with the just released OL 4.2, you can see that if you compile to SWF9 OL is slightly faster than flex: OpenLaszlo still provides SWF8 support since those folks who do consulting still run into sites that don't have the Flash 9 adoption that Adobe reports (or product managers who are very conservative). The performance argument is a good one and can usually sway customers to the new version, but it is nice to be able to write code that will still compile to the older version of Flash without needed to switch languages. Sarah
Hi All

Thanks for the reviews, I'm new to UI patterns/tools.
Can someone make Flex and Laszlo licensing issues more clear as I need a cheap and stable UI SDK for small scale application.

-- Anish Sneh

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