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Meta Stack OverflowStack Overflow clones
[+380] [25] Andrija
[2009-07-03 21:23:21]
[ discussion stackexchange clone ]
[ http://meta.stackoverflow.com/questions/2267/stack-overflow-clones ]

Listed here are clones of the Stack Exchange sites model.

(6) See also blog.bitquabit.com/2009/07/01/one-which-i-call-out-hacker-news - Jakub Narębski
Some Drupal project, "SupportDO": drupal.org/sandbox/HedgeMage/1088372 - Victor Sergienko
(4) related: Is the Stack Overflow source code available? - David Cary
(13) What's the actual purpose for this question? - Lipis
(4) @Lipis some companies want to implement their own branded version of this software on their own sites to supplement their support and/or knowledge base and provide a place where their customers can interact with them in a way similar to this network. All the alternatives I've investigated pretty much suck in comparison. - Aaron Bertrand
[+327] [2010-02-02 15:50:44] Mat

Most active that look like the best bets (as of Jan 2013)

  • shapado [1] Ruby, mongomapper and mongodb. Live site [2], also provide hosted sites for a fee. AGPLv3. Seems to be under active development.

  • OSQA [3] . Django. Live site [4]. GPLv3. More actively developed fork of CNPROG. It has not seen a release since March 2011, so could be abandoned. AnswerHub [5] is the commercial version of same.

  • ASKBOT [6] Django hosting [7], code [8], docs [9], import data [10]. GPLv3. To install type "pip install askbot".

  • LampCMS [11] Live site [12] PHP 5.3, MongoDB LGPL 3 License

  • Question2Answer [13]. Live site [14] PHP, MySQL. Not quite so active [15]. GPL license [16].

  • Q&A [17]. Live Site [18] (currently 404) WordPress Plugin. Actively developed by a company that looks reliable. No longer free; $19 to download (with no membership)

  • Rootbuzz [19] Django, hosting, actively developed, non-free

  • Pligg [20] Has a demo, is free, looks a bit different then stack overflow and is missing some features. It is a little more related to reddit. It is in development still and they are taking suggestions for features, themes, and modules. You can request this stuff and fix bugs in the demo. Make sure to check it out here [21]. Has hosting, is powered by PHP and MySQL, and is customizable and user friendly to the owner and users.

Ones that look sort of finished (as of Jun 2011)

Others that seem to be work in progress

  • FortyTwo [39]. Python, Django, CouchDB. Example site [40]link leads to a 404. Unknown license. Little info. [Last commit in January 2011]

  • kerjakelompok [41]. No example site. Unknown license. Little info.

  • SmartR [42]. No example site. MIT License. Little info.

  • Stack Underflow [43]. C#. No example site. License is "do whatever you want with it" (I haven't defined a formal license yet). Written as a learning project.

  • T002_rails-overflow [44]. Rails. No example site. Unknown license. Little info. Apache license.

  • CNPROG [45]. Django. Live site [46](Update 21/01/2011: link leads to a page which says CNPROG is officially closed). GPLv3. Not a lot of recent activity; last code commit, Oct 2009 (as of Feb 2010). Primarily developed in Chinese, although there are English translations.
    No longer supported according to the website. Was used as base by OSQA & Askbot

Sorted by language

PHP

Python

Ruby

ASP.NET

C#

Java

JavaScript (JSGI)

Did I miss any? Disagree? Please add a comment or update this answer.

And I don't really want to get into listing clones, but I have just come across Answer Bag [68] which seems to be an all-encompassing clone covering everything from aviation [69] through programming [70] to religion [71]. Or maybe that was there first? And Just Answer [72] is another...

Note: AnswerHub was formally Qato.

[1] http://gitorious.org/shapado
[2] http://shapado.com/questions
[3] http://www.osqa.net/
[4] http://meta.osqa.net/
[5] http://answerhub.com/
[6] http://askbot.org/en/questions/
[7] http://askbot.com
[8] http://github.com/ASKBOT/askbot-devel
[9] http://askbot.org/doc/index.html
[10] http://askbot.org/doc/import-data.html
[11] http://www.lampcms.com
[12] http://support.lampcms.com/
[13] http://www.question2answer.org/
[14] http://www.question2answer.org/qa/
[15] https://github.com/q2a/question2answer
[16] http://www.question2answer.org/license.php
[17] http://premium.wpmudev.org/project/qa-wordpress-questions-and-answers-plugin/
[18] http://wpmu.org/questions/
[19] https://www.rootbuzz.com/
[20] http://pligg.com
[21] http://www.pligg.com/demo/
[22] http://github.com/nsanta/openoverflow
[23] http://sourceforge.net/projects/phpancake/
[24] http://phpancake.sourceforge.net/
[25] http://cahoots.sourceforge.net/
[26] http://coordino.com/
[27] http://coordino.com/tour
[28] http://github.com/anantgarg/Qwench
[29] http://anantgarg.com/qwench
[30] https://github.com/anantgarg/Qwench/commits/master
[31] http://code.google.com/p/soclone/
[32] http://code.google.com/p/soclone/source/list
[33] http://opensource.plurk.com/Solace/
[34] https://bitbucket.org/plurk/solace/changesets
[35] http://code.google.com/p/stacked/
[36] http://ra-ajax.org/stacked
[37] http://ra-ajax.org/lawsuit-settled-the-war-is-over.blog
[38] http://drupal.org/project/arrayshift
[39] http://github.com/mcaprari/fortytwo/
[40] http://couch.caprazzi.net/fortytwo/_design/fortytwo/index.html
[41] http://github.com/fuadmuhammad/kerjakelompok/
[42] http://github.com/dkd/smartr/
[43] http://github.com/ripper234/Stack-Underflow/
[44] http://github.com/membrain/T002_rails-overflow/
[45] http://github.com/cnprog/CNPROG
[46] http://www.cnprog.com/
[47] http://www.question2answer.org/
[48] http://cahoots.sourceforge.net/
[49] http://sourceforge.net/projects/phpancake/
[50] http://www.lampcms.com
[51] http://coordino.com/
[52] http://premium.wpmudev.org/project/qa-wordpress-questions-and-answers-plugin/
[53] http://askbot.org/en/questions/
[54] http://github.com/cnprog/CNPROG
[55] http://github.com/OSQA/osqa/
[56] http://code.google.com/p/soclone/
[57] http://opensource.plurk.com/Solace/
[58] http://github.com/mcaprari/fortytwo/
[59] https://www.rootbuzz.com/
[60] http://gitorious.org/shapado
[61] http://github.com/nsanta/openoverflow
[62] http://github.com/membrain/T002_rails-overflow/
[63] http://github.com/dkd/smartr/
[64] http://code.google.com/p/stacked/
[65] http://github.com/ripper234/Stack-Underflow/
[66] http://answerhub.com
[67] http://github.com/fuadmuhammad/kerjakelompok/
[68] http://www.answerbag.com/
[69] http://www.answerbag.com/category/aviation_508
[70] http://www.answerbag.com/category/programming_178
[71] http://www.answerbag.com/category/religion_114
[72] http://justanswer.com/

(3) Not sure where this comment belongs, but I recently deployed and customized Question2Answer in 15 minutes, whereas OSQA took hours and still isn't working right. FWIW! - goodytx
(6) Do all these look like StackExchange sites on purpose?! - Marco Demaio
(1) I noticed how Java was the only language without an entry. According to meta.stackoverflow.com/a/109004/160875 Qato is written in Java. (The original question asked for web apps inspired by the StackExchange system, but didn't specify open source. Some of the other answers mention non-open source implementations of SE, but I had my eye on that None known spot under "Java"!) - Feral Oink
(3) After getting tired of OSQA and its django dependencies, I installed question2answer and worked great so far: pretty complete, lots of plugins. - Deigote
I may be building a stackoverflow clone in the near future - anyone know pros and cons of building it myself from scratch vs. using something like Q&A (the WordPress plugin)? - jbyrd
@ObsessiveFOSS You need just 1 rep to post answers (it's a fundamental right)??? - YatharthROCK
@YatharthROCK I don't know how that text came to be, but the project is abandoned anyway. - ObsessiveSSOℲ
Do any of these clone SE's excellent chat? For my Q&A needs, I'm OK with using the SE family, but that chat is fantastic and I'd love to see it (or something like it) start replacing IRC. - KRyan
@Evgeny Thanks a lot for the list. Any idea which Q&A system has most features? - Osiris Xu
formally or formerly Qato? - Junuxx
Shouldn't Discourse be on here? - Ian Carroll
askoverflow.com is also a clone, I suppose. - Abu
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[+11] [2009-08-20 11:38:43] Michal

codekicker.de [1]

[1] http://www.codekicker.de

it looks great! - Andrija
OMG!!! I read a couple of paragraphs and I actually understood it!!! Do you know what does it means?!! That the subliminal German lessons I hear while sleeping do actually work!!!!! I cannot believe it. :-o :-O I can officially say I understand 25% of German :P - OscarRyz
codekicker was a closed community at first. But now they added openid, cool. - tobsen
Is it open source? - Nilay Parikh
@NilayParikh No, their license indicates it's closed source: All rights to design, code and content of codekicker.de reserved (except where specified otherwise). Source: codekicker.de/impressum - Randy Burden
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[+11] [2009-11-09 20:25:17] Trey Jackson

The beta O'Reilly Answers [1] site.

[1] http://answers.oreilly.com/

Finally the first side which seems to have a more distinct look. - mark
(14) I think the folks at O'Reilly were just doing their thing. i don't think they were trying to clone SO. - Ben
This site is quite dead. For example, Javascript is a "trending topic", but only two questions were asked in September - Casebash
Not a clone...... - 0A0D
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[+9] [2010-08-30 05:07:06] casperOne

I might as well throw my two cents in. I've developed a site from scratch which uses the Stack Overflow model, but it is based on a completely different subject matter ( Super Street Fighter 4 [1]):

http://sf4answers.com

Some differences/extensions:

  • There is an events section [2] which allows for users to search on events related to the game (as well as vote up/down)
  • There is a podcasts section [3] (again, podcasts and episodes can be voted up/down)
  • There is a notes section [4]. Notes differ from questions in that they are one-way projections, there are no replies. Almost like blog entries, but on a specific topic that's indexed all the same.

And there are plans around other forms of data around the game as well.

I've asked a number of questions about (and on, not directly related to) Stack Overflow to help shape functionality:

All of these were used to help shape the development of the site.

[1] http://en.wikipedia.org/wiki/Super_Street_Fighter_IV
[2] http://sf4answers.com/events
[3] http://sf4answers.com/podcasts
[4] http://sf4answers.com/notes
[5] http://stackoverflow.com/questions/735168/how-to-implement-a-reputation-system-like-stack-overflow
[6] http://stackoverflow.com/questions/2297794/how-would-one-use-lucene-to-help-implement-search-on-a-site-like-stackoverflow
[7] http://stackoverflow.com/questions/1996125/how-to-use-jquery-validation-plugin-with-metadata-and-the-jquery-forms-plugin-wi
[8] http://stackoverflow.com/questions/710805/maintaining-message-integrity

your site looks spot-on, I wish that it was an open source project..... Is it? - RJB
@rjb It is not. The new site, One Frame Link is in development, but will probably do Q&A last (I'm focusing on other tools, and as you can see, I need to do design work). Also, I'd probably do the engine much differently than I did it the first time around. However, I might make the original open source, as I don't have much use for it anymore. - casperOne
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[+6] [2009-08-13 14:53:25] user76720

Doctype launched recently, they a have a similar concept to Stack Overflow.

http://doctype.com/

But the visual design focuses too much on the person and not enough on how good an answer is…

DocType closed on 2013-02-14 [1], and they didn't bother to release their codebase.

[1] http://blog.doctype.com/doctype_is_closing_on_the_14th_1

(3) DocType whats that??? blog.stackoverflow.com/2009/08/stack-overflow-and-doctype - jjnguy
(5) Pretty surprising that a site for web designers would chose a text size/weight that makes it look like everything is in bold for emphasis... almost as bad as everything being in caps IMO. - U62
There's a lot of web designers out there who appear to think that's a Good Thing. Heck, I remember the last time I looked at a web design company's website. That thing was horrible! - David Thornley
(1) uh-oh no OpenId ... - user132619
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[+5] [2009-09-01 21:44:45] Sam Saffron

I wouldn't call my communitytracker [1] an SO clone, but it is inspired by it. I got tired of the noise that is phpBB. I am starting to feel the pain now, I need a meta site.

[1] http://community.mediabrowser.tv

mediabrowser rocks! - TheEmirOfGroofunkistan
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[+5] [2011-09-02 12:03:38] Idolon

HashCode [1] (Russian: ХэшКод) - Russian clone of SO.

Also there are RootCode [2] (РутКод) and BitCode [3] (БитКод) related projects, which clone SF and SU respectively.

[1] http://hashcode.ru/
[2] http://admin.hashcode.ru/
[3] http://user.hashcode.ru/

Are these Open Source? - Mob
Nope - don't look so. - Idolon
It's based on OSQA confirmation here. - niki-timofe
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[+3] [2009-11-24 10:00:53] Marek Grzenkowicz

Quick Answers at Code Project: http://www.codeproject.com/script/Answers/List.aspx


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[+3] [2010-01-10 08:56:55] Jeff Atwood

Stack Overflow clone in PHP -- "Qwench"


It appears to be broken. :\ - Ian Carroll
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[+3] [2010-09-14 23:33:24] icco

Inspired by SO: http://www.iFixit.com/Answers

Jeff mentioned them in one of the SO blogs, http://blog.stackoverflow.com/2010/02/our-sidekick-ifixit-com/, although he got it wrong, http://ifixit.com has been around for a while (2003 http://en.wikipedia.org/wiki/IFixit), while Answers had recently been released.


Actually it's a commercial product, available here dozuki.com/Sales/Answers - jmd
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[+3] [2011-05-18 07:39:43] picxelplay

WordPress [1] version:

http://templatic.com/demos/answers

[1] http://en.wikipedia.org/wiki/WordPress

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[+2] [2013-05-15 02:37:07] Linuxios

Here's another, called Verious.

Original Q: Getting 503 Service Unavailable when trying to generate discovery document [1]

Clone: http://www.verious.com/qa/getting-503-service-unavailable-when-trying-to-generate-discovery-document/

[1] http://stackoverflow.com/questions/14912267/getting-503-service-unavailable-when-trying-to-generate-discovery-document

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[+1] [2010-02-16 20:56:20] ripper234

Like many others, I build a Stack Overflow clone [1] as well, mostly as a learning exercise. This one might be the only open-source clone written in C# / ASP.NET MVC [2].

[1] http://ripper234.com/p/open-source-stackoverflow-clone-by-a-n00b-webdev/
[2] http://en.wikipedia.org/wiki/ASP.NET_MVC_Framework

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[+1] [2011-05-11 08:45:39] Piskvor's Semifinite Monkeys

qato.com [1] - not open-source, apparently clones the SE 1.0 model as well (hosting SaaS Q&A sites). It took me a while to notice why the DynDNS community support pages [2] felt familiar.

[1] http://qato.com/answers/index.html
[2] http://www.dyndnscommunity.com/spaces/11/index.html

(1) Why did you not add to the main Answer? - Tshepang
@Tshepang: if you mean this, it specifically says "open source"; I'm unable to get at qato's source anywhere, leading me to the conclusion that it is closed-source, and thus doesn't really fit there. - Piskvor's Semifinite Monkeys
Oh, I missed that. - Tshepang
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[+1] [2011-06-16 04:21:56] Magic

My open source project of a Stack Overflow clone is hosted on GitHub [1].

It's under heavy development. And will add more functions compared to Stack Overflow.

[1] https://github.com/gmagic10/ComCat

This one's been abandoned. It may (not) work. - Ian Carroll
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[+1] [2012-08-31 02:52:07] j08691

http://answers.bitnami.org/ ...


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[+1] [2012-12-14 12:00:26] onokazu

I have created one as a WordPress plugin, if you are interested. Demo here: http://demo.sabaidiscuss.com/


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[+1] [2013-05-15 10:06:48] Cybermaxs - Betclic

Also the Splunk Answer [1] section.

[1] http://splunk-base.splunk.com/answers/

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[+1] [2013-06-11 06:52:51] Robotnik

http://wiki.jammer-store.com/

Seems fairly similar, I don't know if it infringes directly. See the question [1] I posted on this site.

[1] http://meta.stackoverflow.com/questions/183921/what-to-do-with-sites-that-rip-off-stack-exchange

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[0] [2010-08-17 10:50:24] sundar_srd

I managed to get Qwench [1] (a PHP Stack Overflow clone) from inscripts / anantgarg working under IIS 5.1 - with IIRF [2]. Extending to provide search and additional adminstration functions to manage Q&A should make the application more useful.

[1] http://github.com/anantgarg/Qwench
[2] http://en.wikipedia.org/wiki/Rewrite_engine#IIS_.28Microsoft_Internet_Information_Services.29

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[0] [2010-11-19 17:30:44] Adam

Arrayshift [1] is a Drupal project that replicates a lot of the SO functionality. It's currently in Alpha.

[1] http://drupal.org/project/arrayshift

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[0] [2012-05-10 04:10:12] Eran Medan

codingstack.com [1] seems like a new attempt, no risk for SO though...

[1] http://codingstack.com

Any idea what platform they are using (one of the open source clones, or something they wrote?) - Tim Post
@TimPost - Looks like something they wrote (Ruby on Rails based) not sure if it's used by anyone but them, but I doubt it as it has 2 watchers and 1 fork (github.com/usmanasif/CodingStack) - Eran Medan
22
[0] [2012-06-18 20:14:22] Seva Alekseyev

http://ask.badadev.com/

It's in production, but anemic, and prone to spam questions and answers. There's probably a better chance to get bada answers at SO proper.


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[0] [2012-06-24 21:27:52] CodaFi

s41.codeinspot.com [1] Complete with question title, original formatting, images, and profile pics... For [2] || Comparison [3]

[1] http://s41.codeinspot.com/
[2] http://stackoverflow.com/questions/2959299/gray-uisearchbar-w-matching-scope-bar-programmatically
[3] http://s41.codeinspot.com/q/1015456

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[0] [2013-03-02 07:04:22] Nathan Goings

The Unity Answers [1] uses AnswerHub [2]

[1] http://answers.unity3d.com/index.html
[2] http://answerhub.com/

25