Not the first attempted Flash reimplementation[1,2,3]. The GNU one didn’t work all that well back in the day as far as I remember, but then Flash was a moving target at the time.
[1]: https://www.gnu.org/software/gnash/
[2]: http://lightspark.github.io/
[3]: https://github.com/mozilla/shumway
In When SVG almost got network support for raw socketsmozilla
shumway
TypeScript2012–2023
mozilla / shumway · Archived
shumway
Shumway is a Flash VM and runtime written in JavaScript
46Distinct people
50Mentions
2Explicit recommenders
3.7KGitHub stars
What to know before exploring
What it is
Shumway is a Flash VM and runtime written in JavaScript
GitHub
Where it is used
No documented product use was verified in the last source check.
What people are saying
Yes, I really love PDF.js. I was consider switching to Chrome just because of the (proprietary) pdf viewer. But the Chrome PDF viewer even lacks the concept of pages! I had…
fafner used a recommendation phrase. 2 indexed comments match. This is a phrase match, not a verdict.
No classified warning is attached to this page. Read the discussions before treating silence as approval.
Also in these discussions
No other repository is repeatedly linked in the same discussions.
This week on Hacker News
Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 3:56:07 PM UTC.
No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.
Mentions over time
HN mentions by year50 dated mentions
Observed mentions: 2012-02-22 13:23:49 UTC to 2023-03-31 11:33:10 UTC.
Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.
View mention counts and date ranges
| Period | Start (UTC) | End (exclusive, UTC) | Mentions | Submissions | Comments |
|---|---|---|---|---|---|
| 2012 | 2012-01-01 00:00:00 UTC | 2013-01-01 00:00:00 UTC | 8 | 3 | 5 |
| 2013 | 2013-01-01 00:00:00 UTC | 2014-01-01 00:00:00 UTC | 8 | 2 | 6 |
| 2014 | 2014-01-01 00:00:00 UTC | 2015-01-01 00:00:00 UTC | 4 | 1 | 3 |
| 2015 | 2015-01-01 00:00:00 UTC | 2016-01-01 00:00:00 UTC | 6 | 0 | 6 |
| 2016 | 2016-01-01 00:00:00 UTC | 2017-01-01 00:00:00 UTC | 5 | 0 | 5 |
| 2017 | 2017-01-01 00:00:00 UTC | 2018-01-01 00:00:00 UTC | 4 | 0 | 4 |
| 2018 | 2018-01-01 00:00:00 UTC | 2019-01-01 00:00:00 UTC | 5 | 1 | 4 |
| 2019 | 2019-01-01 00:00:00 UTC | 2020-01-01 00:00:00 UTC | 4 | 0 | 4 |
| 2020 | 2020-01-01 00:00:00 UTC | 2021-01-01 00:00:00 UTC | 4 | 1 | 3 |
| 2021 | 2021-01-01 00:00:00 UTC | 2022-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2022 | 2022-01-01 00:00:00 UTC | 2023-01-01 00:00:00 UTC | 1 | 0 | 1 |
| 2023 | 2023-01-01 00:00:00 UTC | 2024-01-01 00:00:00 UTC | 1 | 0 | 1 |
From the project README
An excerpt from the repository, fetched Nov 13, 2026.
Read the project’s introduction
Shumway
Shumway is an HTML5 technology experiment that explores building a faithful
and efficient renderer for the SWF file format without native code
assistance.
Shumway is community-driven and supported by Mozilla. Our goal is to
create a general-purpose, web standards-based platform for parsing and
rendering SWFs. Integration with Firefox is a possibility if the experiment
proves successful.
Getting started
Online demo
For an online demo, visit:
http://mozilla.github.io/shumway/examples/racing/
Or see all the demos at http://mozilla.github.io/shumway/
Extension
Install the Firefox extension: http://mozilla.github.io/shumway/extension/firefox/shumway.xpi
This development extension should be quite stable but still might break from time to time.
Also, note that the development extension is updated on every merge and by default Firefox will
auto-update extensions on a daily basis (you can change this through the
extensions.update.interval option in about:config, time is in seconds).
To build the Firefox extension: use grunt firefox.
Contributing
Development
See the wiki.
If you don't want to hack on the project or have little spare time, you still
can help! Just install the Firefox extension, test it on SWFs in the wild,
and report any problems or unimplemented features.
Our GitHub contributors so far:
https://github.com/mozilla/shumway/contributors
You can add your name to it! :)
The easiest way to get started is to grep for TODOs and implement them.
Additional resources
Talk to us on IRC:
#shumway on irc.mozilla.org
Post on our mailing list:
dev-shumway@lists.mozilla.org
Subscribe either using lists.mozilla.org or Google Groups:
https://lists.mozilla.org/listinfo/dev-shumway
http://groups.google.com/group/mozilla.dev.shumway
Read the full README on GitHubWhat Hacker News says
50 sourcesThat's what Shumway did (it's now unmaintained), and what Ruffle does.
https://github.com/mozilla/shumway
https://ruffle.rs/
In I still use FlashI was shadowbanned by dang for expressing disappointment in some HN commenter's defense of coronavirus conspiracy videos. I really wish there were a way to delete my account and all my posts, but this is apparently the best they can do.
also, you may be interested in the openflash project
https://github.com/open-flash
and the shuobject api
https://github.com/mozilla/shumway/blob/16451d8836fa85f4b16e...
In Adobe to remove Flash Player from web site after December 2020I forgot to mention the myriad ways that flash would interact with the browser and the operating system, with swfs often designed to interact with browser javascript in particular, in platform and browser specific ways. the various network protocols, RTMP streaming, prioprietary video codecs, ALPHA MASKED video, the CSS parser and styling engine! the API has everything but the kitchen sink. You can have a look at the sorts of challenges you're in for by looking at Shumway's issues register here:
https://github.com/mozilla/shumway/issues
In Adobe to remove Flash Player from web site after December 2020It should be possible to make a Flash player that works for the most part using web technologies (e.g. WebAssembly). I remember Mozilla created Shumway (https://github.com/mozilla/shumway) but it looks like they have given up on it.
In Nitrome to convert its Flash game library to HTML5There was an effort to run Flash using JS by Mozilla, called
Shumway, now in Mozilla Graveyard.
https://github.com/mozilla/shumway
In Flash Is Responsible for the Internet's Most Creative EraI really hope this works, but I fear it will die a shumway death. One of the issues is there are two complete run-times inside of Flash. AVM1 (for AS1/2) and AVM2 (for AS3). AS1/2 is much easier to program and probably emulate. AS3 was much more advanced and was actually a pretty good language. Adobe should release the source, but probably doesn't due to all the security holes that probably are waiting to be found. Of course, that is speculation.
[https://github.com/mozilla/shumway]
[https://en.wikipedia.org/wiki/ActionScript]
In Ruffle – An Adobe Flash Player Written in Rust Compiled to WebAssemblyShumway is in a spot where they need ActionScript 3 support to play more complex content. ActionScript 3 is based on ECMAscript 3. ES3 has support for some depreciated features such as E4X. To do this someone would need to compile the Tamrin AS/ES engine using something like WebAssembly.
https://github.com/mozilla/shumway/wiki/Intro
https://developer.mozilla.org/en-US/docs/Archive/Mozilla/Tam...
https://webassembly.org/
In Pale Moon Browser Continues Support and Development of XULWe really need to resurrect Shumway: https://github.com/mozilla/shumway At this point I consider Shumway to be a retro console emulation project.
In Pale Moon Browser Continues Support and Development of XULThree months of no commits is not enough to declare a project dead.
As for Shumway, looking at the commit history[0], the last commit was over 2 years ago.
[0] https://github.com/mozilla/shumway/commits/master
In Shumway: Flash implementation in JavaScriptShumway: Flash implementation in JavaScript
90 points · Open discussionFor those eager to directly witness some SWF running in JavaScript:
http://mozilla.github.io/shumway/examples/racing/
(via aforementioned https://github.com/mozilla/shumway/ )
http://gordonjs.s3.amazonaws.com/trip.html
(via https://github.com/tobytailor/gordon/wiki )
https://google-developers.appspot.com/swiffy/showcase/snake_...
(not reading SWF directly but running converted script; via https://developers.google.com/swiffy/showcase/ )
In Adobe Flash’s Gaming Legacy and My Efforts To Save Ithttps://github.com/mozilla/shumway
is supposed to be an implementation of the Flash VM in typescript, But it can't even run in latest Firefox browser anymore apparently and no commits from 2 years.
In Is WebAssembly the Return of Java Applets and Flash?From Mozilla yes, but there was some activity by others this year: https://github.com/mozilla/shumway/pull/2442
In Internet is losing its memory: CerfShowing the 15 most recent of 50 sources. Enable JavaScript to search and browse every indexed mention.