Flash vs. Silverlight: What Suits Your Needs Best?


With the release of Silverlight 1.0 and its subsequent versions, a debate started among designers and developers regarding choosing between Flash and Silverlight. Silverlight faces difficulties in capturing the market because of the maturity of Flash. However, Silverlight has managed to keep up by including certain features that designers and developers have always wanted to see in Flash, such as search engine optimization. In this article, we will discuss some of the technical differences between Flash and Silverlight to help you choose the technology that best suits your needs.


Flash uses the frame-based animation model. In frame-by-frame animation, we create an object for each frame to produce an animation sequence. For example, if you want to move something across the screen in 3 seconds, calculate how many frames 3 seconds will take, then calculate the matrices required for each frame along the way. Keep in mind that the player won’t actually maintain a frame rate unless you embed a blank audio track; otherwise, 3 seconds might turn out to be 2 or 6 or 5.

Adobe Flash Animation1

Silverlight is based on the WPF animation model, which is time-based instead of frame-based, so you define the start and end conditions, and it figures out how to do it. No need to deal with matrices like with Flash. Also, no need to calculate the positions of objects in various frames.

Microsoft Silverlight Animation2

File Size

Flash uses a compressed format, and text and images are embedded in the movie, hence the file size of a Flash component is relatively small.

Text representation in Adobe Flash3

Silverlight uses XAML for its description language, and it is non-compressed, so the size of a Silverlight component is usually larger.

Text representation in Microsoft Silverlight4


ActionScript is used to program Flash objects. ActionScript is an object-oriented language with a full range of controls for designing user interfaces. And it can be integrated with back-end technologies that use other languages and frameworks, such as PHP, ASP and Ruby On Rails. It comes with a huge, powerful class library for developing online browser-hosted applications and stand-alone desktop applications.

Action Script5

For Silverlight scripting, you can choose from among a number of programming languages such as Visual C#.Net and Visual Basic.Net, including client-side scripting with JavaScript. C# and VB.NET can be used to write managed code that runs on and uses all of the enhancements and capabilities of Microsoft’s .NET framework.

Visual Basic6

Video And Audio

Flash supports multiple video formats. The latest codec is very high quality, and the bandwidth usage is nice. There is one problem, though: if you create a tool that outputs Flash content, the formats it supports aren’t really used by anyone else. The original video codec, Sorenson’s proprietary H.263 implementation, is a mutant version of H.263. The compression follows the spec fairly closely, but a bunch of features were left out, and you can’t exactly just go find complete specs on how to build your own encoder.

Video Codec7

Silverlight implements the industry-standard VC-1 codec for video, and supports WMV and WMA. Just about everyone already has Windows Movie Maker, but if someone doesn’t, it’s not a big deal because Microsoft makes available a free SDK encoder for producing WMA and WMV. So, not only would you be using formats that people would more likely be able to encode themselves, but Microsoft provides your product with SDKs if you want to do the encoding yourself.

Sound Processing

ActionScript offers a set of sound classes that can be used to generate and control sound in a movie. You can add sounds from the library while the movie clip is playing and control those sounds. If you do not specify a target when you create a new sound object, there are methods to control sound for the whole movie.

Sound Processing8

Silverlight doesn’t have the low-level audio APIs you would need to write an audio application in the browser. It doesn’t even support playback of WAV files because .NET has very little audio playback support.


Flash provides rich accessibility features for those who have hearing and vision problems or who rely on keyboard shortcuts. Providing captions for video solves accessibility challenges for people who are deaf and hard of hearing, but people who are blind or have low vision or other physical disabilities need the video playback controls to be keyboard-accessible and to function properly with assistive technologies such as screen readers and screen magnifiers. Users who rely on keyboard access can use a variety of familiar shortcuts to control video. Buttons such as “Play/Pause,” “Stop,” “Rewind,” “Mute” and “Closed Captions” can be tabbed to and activated with the spacebar. Slider controls such as for volume and playhead position controls can be accessed via the arrow keys, and the “Home” and “End” keys can be used to skip directly to the beginning or end of a range. The volume slider also accepts numeric keys to set playback audio levels in one quick step.




Silverlight 3 is the first browser plug-in to provide access to all system colors, allowing people with partial vision to use familiar operating system controls to make changes, such as switching to high-contrast color schemes for ease of readability. These features are far fewer than those provided by Flash.

Platform Compatibility

Flash supports Windows Vista/XP/2000, Windows Server 2003/2008, Mac OS 10.1/10.5 (PowerPC), Mac OS 10.1/10.5 (Intel), Linux 5, openSUSE 11, Ubuntu 7.10 or later and Solaris 10.

Silverlight supports only Windows Vista/XP/2000, Windows Server 2003/2008, Windows Mobile 6, Mac OS 10.1/10.5 (PowerPC) and Mac OS 10.1/10.5 (Intel). Because Linux and Solaris support is missing, users of those operating systems won’t be able to experience Silverlight on their machines.

Text Representation/SEO

Flash stores fonts using shape definitions and the player doesn’t understand TTF, hence we cannot separate the text layer from the movie. Typically the text written on a flash component was not SEO friendly however Adobe has made the modifications to Flash so that it will be indexable, and the search engines have begun to index Flash.

Currently Google is the only search engine that is noticeably reading Flash files. They have worked closely with Adobe to develop the right toolset for the Googlebot in order to read the files for indexing. Yahoo is working on it and MSN is working with their own format, Silverlight, so they probably won’t be developing the toolset necessary to read Flash files.

To read more about how to make Flash SEO friendly, please read the following articles:

In Silverlight applications, user interfaces are declared in XAML and programmed using a subset of the .NET Framework. XAML can be used for marking up the vector graphics and animations. Text is deployed on web server as separate entity and can be read and accessed separately. Textual content created with Silverlight is searchable and indexable by search engines as it is not compiled, but represented as text (XAML).

Supported Image Formats

Flash supports almost all image formats.

Silverlight supports only PNG and JPEG file formats. Some other file formats are supported by Silverlight but in a limited way. A full list can be found here14.

Socket Programming

The XMLSocket object implements client sockets that allow computers running the Flash player to communicate with a server computer identified by an IP address or domain name.

To use the XMLSocket object, the server computer must run a daemon that understands the protocol used by the XMLSocket object. The protocol is as follows:

  • XML messages are sent over a full-duplex TCP/IP stream socket connection.
  • Each XML message is a complete XML document, terminated by a zero byte.
  • An unlimited number of XML messages can be sent and received over a single XMLSocket connection.

Socket Programming with Flash15

Silverlight doesn’t support socket programming. Silverlight supports sockets programming through the System.Net.Sockets namespace. Silverlight supports asynchronously sending data back and forth across a socket over ports ranging from 4502 to 4534. Silverlight supports cross-domain socket communications between a Silverlight application and any server, provided that a special security policy file is in place on the server.

Webcam Support

Flash has webcam16 and microphone support for live video and audio transmission, and using them is really easy in Flash. It takes only a few lines of ActionScript code to invoke the camera object17.

Camera.get18 Returns a default or specified camera object, or null if the camera is not available.
Camera.setMode19 Sets aspects of the camera capture mode, including height, width and frames per second.
Camera.setMotionLevel20 Specifies how much motion is required to invoke Camera.onActivity(true) and how much time should elapse without motion before Camera.onActivity(false) is invoked.

Silverlight doesn’t support webcam or microphone.


The Flash deployment package contains only a single Shockwave (SWF) file, and all images, text and animations are incorporated in this file. Because of the compressed nature of a Flash component, its images and text are not indexed by search engines, and thus not searchable.

The deployment process of Silverlight is far more complex; all individual components need to be deployed separately. The following components typically get sent to the client for each Web request of Silverlight:

  • XML files,
  • DLL files (if necessary),
  • Silverlight.js file,
  • Any other JavaScript file,
  • Resources (images, audio, video).

Silverlight Deployment21

Read the full documentation22 on Silverlight deployment.

Windows Application

A Flash movie can be compiled into a Windows application and run as a standalone EXE file. It can also be played on a desktop that has an appropriate Flash player.

Flash EXE Builder

Silverlight doesn’t support playing the movie as a Windows application.

Media Streaming

Flash provides no such service to host the content and application with them. Thus, building a video website with Flash is not as cost-effective as building one with Silverlight.

Microsoft Silverlight Streaming by Windows Live is a companion service for Silverlight that makes it easy for developers and designers to deliver rich media as part of their Silverlight applications. The service allows Web designers and developers to host and stream cross-browser media and interactive applications that run on both Windows and Mac. This service can be combined with Microsoft Expression Studio and other third-party tools to create and develop interactive contents.

Silverlight Streaming by Windows Live is currently in beta testing and offers 10 GB of free hosting for rich-media applications.

Microsoft Silverlight Streaming23


Selecting the right technology for rich Internet applications is often critical, and choosing between Flash and Silverlight depends entirely on your requirements. If you expect that some of your users will be on Linux or Solaris, then you should go with Flash. If you want your website to be indexed by search engines, then Silverlight may be better.

Besides, as Doug S. is points out in the comments, it’s worth noticing that a minority of web users actually have a Silverlight plugin installed on their machine, while most users do have Flash-support. The Flash Player 9 and higher support streaming of the H.264 video codec which means anyone with a video program that can output an MP4 can stream to Flash. There are literally hundreds of free apps on Mac, PC and Linux that can do this. It’s also important to mention that the latest version of Flash Player supports 3D rendering while Silverlight does not and that SWF, FLA, FLV, and AS are all open-standard formats, while Silverlight is 100% proprietary.

The following table summarizes the features discussed above. Rather than including arrows to indicate whether each platform has a particular feature, we’ve simply marked “better” to show the areas in which each technology beats out the other.

Features Flash Silverlight
Animation better
File size better
Scripting better
Video/Audio better
Sound processing better
Accessibility better
Platform compatibility better
Text representation/SEO better
Supported image formats better
Socket programming better
Webcam support better
Deployment better
Windows application better
Media streaming better

Further Resources

The following articles are suggested for further reading:



  1. 1 http://www.webdesigndev.com
  2. 2 http://blogs.conchango.com/
  3. 3 http://wareseeker.com/
  4. 4 http://www.microsoft.com
  5. 5 http://actionscript.org/
  6. 6 http://joymon.googlepages.com/
  7. 7 http://technet.microsoft.com
  8. 8 http://www.prepresstraining.com/
  9. 9 http://lh5.ggpht.com/_D_LHhy5fi8o/SUQhlbxnK2I/AAAAAAAAADA/E34em8f43fw/WhistlerBlue_thumb.png
  10. 10 http://lh5.ggpht.com/_D_LHhy5fi8o/SUQhlbxnK2I/AAAAAAAAADA/E34em8f43fw/WhistlerBlue_thumb.png
  11. 11 http://lh5.ggpht.com/_D_LHhy5fi8o/SUQhlbxnK2I/AAAAAAAAADA/E34em8f43fw/WhistlerBlue_thumb.png
  12. 12 http://www.hochmanconsultants.com/articles/seo-friendly-flash.shtml
  13. 13 http://googleblog.blogspot.com/2008/06/google-learns-to-crawl-flash.html
  14. 14 http://www.accusoft.com/ig-silverlightformats.htm
  15. 15 http://www.adobe.com/
  16. 16 http://www.youtube.com/watch?v=qYmYkMYGp5s
  17. 17 http://www.adobe.com/support/flash/action_scripts/actionscript_dictionary/actionscript_dictionary119.html
  18. 18 http://www.adobe.com/support/flash/action_scripts/actionscript_dictionary/actionscript_dictionary124.html
  19. 19 http://www.adobe.com/support/flash/action_scripts/actionscript_dictionary/actionscript_dictionary135.html
  20. 20 http://www.adobe.com/support/flash/action_scripts/actionscript_dictionary/actionscript_dictionary136.html
  21. 21 http://www.microsoft.com/
  22. 22 images/Silverlight_Deployment_Guide.doc
  23. 23 http://msdn.microsoft.com
  24. 24 http://www.learn-silverlight-tutorial.com/
  25. 25 http://silverlight.net/forums/t/3015.aspx
  26. 26 http://www.shinedraw.com/multimedia/flash-vs-silverlight-apply-theme-or-style/
  27. 27 http://dobbscodetalk.com/index.php?option=com_myblog&show=The-Flash-Silverlight-Fight.html&Itemid=29

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  1. 1

    Try to do something like http://www.ladimolnar.com/Fractalia/ in Flash/Flex and then we’ll talk.

  2. 302

    Liberty City Cops Rules!!!!!!!!!!!!!!!!!!!!!!!!

  3. 603

    I think that the comment are too much more biased than the article itself. Actually the article is nice, and just traces a parallel between both tools. Obviously the writer has no one (or very small) experience with SilverLight. But – what the heck – I doubt that anyone here (or anywhere) can tell that has DEEP experience in SL!

    Anyway, I have seen people above speaking in defense of Flash and others doing the same regarding to SL – what in my opinion is very childish since as developers we would be always focused on find the better tools instead to fight each other in name of big companies. Come on, people – not MS neither Adobe will be sharing their revenues with you just because your passionate comments! LoL!

    Anyway, back to the point I think that both platforms has advantages and disadvantages. I am a Flash guy and a .NET developer for years now and my better wish would be to see Flash incarnated into the .NET platform (AKA SilverLight).

    However, as usual (and again!) Microsoft has released a product in a rush with an apparently unfinished tool instead to make their homework accordingly. It sounds at least as stupidity to release a web tool by ignoring Linux.

    I am about to develop a desktop application for the company I work for because they are MS freak and they want one of our old Flash tool converted into SL. It will be very fun for me! But obviously my situation is very comfortable as I will be paid to learn SL as by my bosses request, then even if SL becomes a big failure in the future I won’t have lost anything…

    However, for all the ones that work as freelance developers, I think that it is a dangerous bet. At least for a while. It may mean a big learning curve, and after then, ends as a faulty idea. In my almost 30 years of experience I have seen lots of great nice tools come and go. Anyway, I think that is better to be careful.

    I think that SL MAY be a great tool some day, but for now it just look like a nice golden pill. The fact is that I don’t think that it is fair enough to compare a mature tool with over a decade of attested success with a new born. It is not fair for both ones.

    Let’s try again in 3 years or so. And, of course only if it become Linux friendly. Otherwise, not even in century!

    PS: Just for the records – I am NOT a Linux user – I am only a realistic and conscientious developer!


    • 904


      You are exactly correct about neither company sharing profits for passionate comments. To me the important thing is which to is versatile and usable with many platforms and which has mad itself exclusive only to its developers other software tools,

      No different to the computer manufacturers that made their systems capable of using any RAM/video card/network card/etc… versus those that made their equipment proprietary. When you go the proprietary trying to force people to all you products, you force so many more away, that do not want to pay your Premium cost to use it.

  4. 1205

    This article and all of its comments agents Flash are written by serious Flash amateurs, so I would not consider it as any reference point. Just looking on Silver lite code makes me laugh loudly. You have to write 10X more than in flash to do the same thing, and when rush hour, that is the only thing that meters! My vote is for Flash in all aspects!

  5. 1506

    I think that until now, flash and silverlight are two completely different products and any comparison is just to be. Any real-life deleloper will certainly manage both of the environments, ‘do’ the job and go to next one….but i also think that in the same world, noone will ever have (i hope) to choose and propably noone will ever do.
    Silverlight development is presented, supported and distributed as a business application platform and is build uppon a rather large portion of the not-so-young .NET framework that will always be a business platform. With Silverlight you would propably create an Eshop, a CRM, an Enterprise or Educational Software, a Navigation Application or any type of content access software and you could do it rather easily by using the various set of tools and technologies that .NET has to offer. And even more you can do all that Accelerated, Animated and with some Effects , just like Flash.
    You have to be already a .NET developer and value the development-style that it promotes and it doesn’t matter if SL has disadvantages over Flash, or not still running on some OS – That is product specifications.
    As for Flash, i would consider using it if i had to create a very-very-very impressive presentation over the web, a commercial or even a game that would not require any serious communication with a server or data-exchange.
    To simplify things consider Silverlight a platform for web-developers with design skills (and demands) and Flash the one for web-designers with code development skills.

  6. 1807

    i want car game script for flash

  7. 2108

    Can anyone help me i want to learn Silveright or flash witch is good i need a honest answer plz guys

  8. 2409

    Time proves it Silverlight is officially dead now

    Microsoft dropping it in favor of HTML5

  9. 2710

    Silverlight is not dead! HTML5 and Flash are a subset of features in Silverlight 4. High end buisness applications such as SAP are written in Silverlight. Windows Phone will always use it. As far as the Mental Miget Colony of “open sores” software goes, you will always be angry because you couldn’t cut it with MIcrosoft products for development. So enjoy your 4% market share.

  10. 3011

    I am not an animator or website maker. I am just a normal browser of websites, and play games and all that. I have to give an F to Adobe Flash. It always crashes and freezes my browsers up. Ever since Adobe took it over from macromedia, they ruined it. Macromedia Flash was much more stabler than now. I decided to completely remove Adobe Flash and use an alternative on my Windows XP system. Silverlight for my window based browsers, or the Open Source Gnash which can be used for Mozilla based browsers, K-Meleon, Opera and Chrome. Gnash is based basically on the old Macromedia Flash Player without the bloatware of Adobes. The flash player was not a security problem that Adobe made it out to be. It was just an excuse by them to add extra stuff to it that did not need it. The security issue was with Microsoft. Now, to go back to Gnash. I had it installed on a Ubuntu linux like system before, and found that it was much more stable with no crashes, freezes or script stop running error messages. Plus, it does not eat up all the resources like Adobe Flash Player does. Gnash plays Adobe Flash 8 scripts, and some of 9s. I am trying to go away from all Adobe junk lately like using Foxit Reader and all that. There are only three flash player programs out there for Windows system and they are Adobe Flash, Gnash and Silverlight. Maybe all the animators who make games and all that might want to check out Gnash since they also have a programmer program with it on building flash. I know that Adobe flash does hurt people who have older computers. I would prefer using Gnash over the other two because it is easier to use, and not a headache for people who loves to play games and all that. I really do not want to see a message all the time to update my Adobe Flash player when I have the latest update from the other two when they are installed.

  11. 3312

    A lot of your points don’t seem credible enough, not enough evidence…

    One major flaw is the comparison of “what is a better animator” – a terrible approach!
    Flash was intended to be a fully fledged animation tool for frame by frame, tweening and more, your comparison is biased and does not represent fact!

  12. 3613

    For the last 7 years as hobbyist I have been coding during my spare time using varies programming software tools. I have used C,Basic,Assembler and C# to program PIC/ ATMEL controller. I have spend almost 3 years trying build site from scratch using AS2 and AS3 using flash (Happy with the result) and PHP CMS (Epic failure but awesome) just for fun. Although, I am not a professional developer I have to say that I have no regret learning Adobe AS2-AS3 and it’s programming environment. It’s simply exciting and fun and the learning curve is so smooth since there’s a vast amount of community help resource out there. This is in contrast Silverlight. Saw it on “Start Program Menu” so was curious to find out more. Spend 8-10 hours (1 whole day) reading and watching their tutorials and realized that it’s the worst programming language (XAML) ever, in comparison any other AS3,PHP,AJAX etc. It lacks of maturity in term of coding and user friendly environment just to mention a few. For e.g Adding Button to make it appear the way you want it you have to write so many line of codes. “This is like going back to Square one after gone so far ahead”, Once again another epic fails product from Microsoft one just like Window Vista .

  13. 3914

    Dear Len Heng. “epic fail product from microsoft”? I’m afraid that “epic fail” is only your comment, and really big one. Obviously you are a kid who doesn’t know anything about software engineering and hasn’t done even a high school…

  14. 4215

    Flash is just afraid of silverlight in terms of superb animation.

  15. 4516

    Zignals is using FLASH/ FLEX….they dropped Silverlight like a hot potato.


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