Listed here are clones of the Stack Exchange sites model.

  • 17
    related: Is the Stack Overflow source code available? – David Cary Oct 19 '11 at 23:58
  • 65
    What's the actual purpose for this question? – Lipis Jun 21 '12 at 14:41
  • 34
    @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 Jul 12 '12 at 13:15
  • 14
    Isn't StackExchange itself a clone of other Q&A sites? Q&A sites with reputation points for good answers have been around for years - I joined Perlmonks back in the year 2000 (it's still going strong). I see SE as a fairly recent arrival. – A E Nov 19 '14 at 10:08
  • 5
    Some companies want to host their own, internal, private Q&A sites. – lambmj Jun 26 '15 at 23:27

37 Answers 37

up vote 715 down vote
+400

Stack Exchange has released an updated, feature-complete version of the Stack Overflow engine which is now available for enterprise use. You can read more about that here

The Stack Exchange engine is available for use

but if that does not meet your needs, there are several third-party tools that try to clone at least some of the functionality here.

Most active that look like the best bets

Open source

Not open source

  • AllAnswered: Django. Include Q&A in its knowledge management system. Not Free.

  • AnswerHub: Java. Live site. Enterprise Q&A by the people who created OSQA. Not free.

  • Confluence Questions: Java. Enterprise Q&A developed and supported by Atlassian. Not free.

  • Haydle: SaaS, free 30 day trial. Haydle is focused on being a private, internal Q&A system.

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

  • Quandora

  • Rootbuzz: Django, hosting, actively developed, non-free

  • SabaiDiscuss: commercial WordPress Plugin

  • Programlama: Python, flask (In Turkish)

  • Unity Answers: Allowed topics are the Unity editor and C# (the site is free and in English)

Ones that look sort of finished

  • shapado: Ruby, mongomapper and MongoDB. Live site, also provide hosted sites for a fee. AGPLv3. Seems to be under active development.

  • OSQA: Django. Live site. GPLv3. More actively developed fork of CNPROG. OSQA is in maintenance mode, with security and Django platform updates, but few new features. AnswerHub has replaced OSQA as DZone's primary Q&A solution.

  • openoverflow: Ruby, PostgreSQL, Haml. MIT license. No example site, and I can't find anyone using this one. Not a lot of recent activity; last code commit, May 2009.

  • phpancake: PHP, Zend framework, MySQL. Live site. MIT license. Last activity Jan 2010. Renders very poorly in some browsers.

  • cahoots: PHP, MySQL. GPL, MIT license. Officially inactive; demo site offline; last update Aug 2010.

  • Coordino: PHP, MySQL. MIT license. feature tour;

  • Qwench: PHP. Example site (no pages except question list). No activity since Dec 2009.

  • soclone: Django framework. MIT license. Seems to have gone stale in Nov 2008 (and only started on Google Code at the end of Oct 2008).

  • Solace: inactive

  • QPixel: Demo. Rails, SQLite. MIT license

  • Kliqqi: Demo. PHP, MySQL. Different look, hosting available. Not active, CC-BY 3.0 license

  • stacked: ASP.NET, Ra-Ajax, ActiveRecord ORM. GPLv3.

  • Arrayshift

Others that seem to be work in progress

  • Asking: Perl, Mojolicious. Perl License (Artistic). Little documentation at this point. GitHub repository README.md in Portuguese.

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

  • kerjakelompok: No example site. Unknown license. Little info.

  • SmartR: No example site. MIT License. Little info.

  • Stack Underflow: 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: Ruby on Rails. No example site. Unknown license. Little info. Apache license.

  • CNPROG: Python/Django. Project officially closed. Was used as base by OSQA & Askbot.

  • Kunjika: Python, Flask, and Couchbase. GNU GPLv3 or later. Documentation is here.

  • QARoR - open source questions & answers platform for Ruby on Rails. Here is the demo and source on GitHub. Released under MIT License.

Sorted by language

PHP

Perl

Python

Ruby

Java

Scala

ASP.NET

MEAN (MongoDB, Express, AngularJS, and Node.js)

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

  • 19
    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 Mar 8 '12 at 16:55
  • 26
    Do all these look like StackExchange sites on purpose?! – Marco Demaio Apr 3 '12 at 20:10
  • 2
    I noticed how Java was the only language without an entry. According to meta.stackexchange.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"!) – Ellie Kesselman Apr 29 '12 at 1:12
  • 7
    After getting tired of OSQA and its django dependencies, I installed question2answer and worked great so far: pretty complete, lots of plugins. – Deigote Jun 6 '12 at 11:50
  • 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 Aug 12 '12 at 1:15
  • @ObsessiveFOSS You need just 1 rep to post answers (it's a fundamental right)??? – Yatharth Agarwal Sep 8 '12 at 17:26
  • 2
    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 Dec 7 '12 at 5:43
  • 7
    Shouldn't Discourse be on here? – StackExchange User Apr 16 '13 at 0:17
  • 1
    shapado only receives translation updates for over a year now, gitorious.org/shapado/shapado/activities. Likewise, OSQA also isn't very active with a mere 5 commits this year (github.com/dzone/osqa/commits/master). – Nico Schlömer Nov 3 '13 at 15:58
  • 3
    @disgruntledgoat Why remove QARoR? – Adam Davis Apr 28 '14 at 15:07
  • 2
    @Adam although there is a section for "half finished clones" that one didn't look very developed at all. Also it looks like the person who added it is the developer; I thought that would count as spam. If others think the project is fine, go ahead and put it back. – DisgruntledGoat Apr 29 '14 at 9:08
  • 3
    Hello, Im the QARoR developer and put it into this topic. What can i say more about development... StartX Stanford already use QARoR, so its not that bad right? There are few apps here which "didn't look very developed at all" for example T002_rails-overflow. DisgruntledGoat, give people a proper choice. @AdamDavis if you think its interesting app, do us a favor and put it back. Thank you! – mateuszdw Jul 12 '14 at 8:46
  • 1
    Saying AnswerHub is a clone of Stack Exchange is basically saying that any Q&A site with quality is a clone. Following that logic let's add Quora as a clone! – the_OTHER_DJMethaneMan May 20 '15 at 15:43
  • 1
    @Evgeny Thanks for an awesome answer! I'm trying to look for the ones that has an API using which I can include a similar Q&A inside my mobile app. I am still to find an open source one. Do you know one by any chance ? – Shobhit Puri Jul 19 '15 at 20:14
  • 5
    This answer needs an overhaul. Plenty of things are now stale, or not in active development. – ankitjaininfo Jul 2 '16 at 14:28

The beta O'Reilly Answers site.

  • Finally the first side which seems to have a more distinct look. – mark Sep 15 '10 at 12:37
  • 20
    I think the folks at O'Reilly were just doing their thing. i don't think they were trying to clone SO. – Ben Oct 30 '10 at 19:15
  • This site is quite dead. For example, Javascript is a "trending topic", but only two questions were asked in September – Casebash Oct 5 '12 at 4:55
  • 1
    It's over. O'Reilly now uses Getsatisfaction – rds Aug 24 '14 at 16:09

codekicker.de

  • codekicker was a closed community at first. But now they added openid, cool. – tobsen Feb 26 '10 at 20:39
  • Is it open source? – Nilay Parikh Jan 20 '12 at 10:48
  • @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 May 18 '12 at 20:16

HashCode (Russian: ХэшКод) - Russian clone of SO - Incorporated by SE and is now the official Russian version of StackOverflow.

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

  • Are these Open Source? – Mob Sep 12 '11 at 13:13
  • Nope - don't look so. – Idolon Sep 21 '11 at 19:25
  • 2
    It's based on OSQA confirmation here. – Niki-Timofe Jun 8 '12 at 18:19
  • 1
    Hashcode has turned into ru.stackoverflow.com at 1.04.2015. There are however some sites of the same network (e. g. math.hashcode.ru) which remain intact after the merge. – Vlad May 23 '15 at 14:50
  • @Vlad , Hi Vladimir, Is ru.stackoverflow.com Subsite Or Site aquired by stackoverflow ? – Pratik C Joshi May 26 '15 at 9:56
  • 1
    @jQuery.PHP.Magento.com: Well, ru,stackoverflow.com was created from a regular area51 request, and hashcode.ru was merged into the new site. – Vlad May 26 '15 at 10:07

I wouldn't call my communitytracker 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.

  • The link is broken. – Vova Jan 17 '16 at 7:44

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, and they didn't bother to release their codebase.

  • 3
    DocType whats that??? blog.stackoverflow.com/2009/08/stack-overflow-and-doctype – jjnguy Aug 13 '09 at 14:57
  • 6
    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 Aug 13 '09 at 16:22
  • 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 Aug 13 '09 at 21:21
  • 1
    uh-oh no OpenId ... – user132619 Aug 16 '09 at 22:29

Stack Overflow clone in PHP -- "Qwench"

WordPress version:

http://templatic.com/demos/answers

  • There seems to be no answers provided on this site – ahorn Apr 26 '15 at 20:56

Inspired by Stack Overflow: http://www.iFixit.com/Answers

Jeff Atwood mentioned them in one of the Stack Overflow blogs, 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.

Here's another, called Verious.

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

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

Update: As of today May 9, 2017, this site has been dead for some time and is now gone from the internet.


There is also MetaOptimize's community QA site. It is clearly based on the SE model in its design, style, functionality, etc. It's content is a mix of Stack Overflow programming questions and Cross Validated machine learning & data visualization questions, with perhaps bits of other SE sites thrown in. Their self description is:

Where scientists ask and answer questions on machine learning, natural language processing, artificial intelligence, text analysis, information retrieval, search, data mining, statistical modeling, and data visualization!

The design is almost identical. Just replace rep with karma, badges with kudos, and tags with...well, tags. They even have diamond mods and green boxes for accepted answers!

A user profile:


Update: As of today (May 9, 2017), the site has been dead for some time and is now gone from the internet.

  • This looks good. Is it PHP opensource? – Pacerier Jan 10 '15 at 17:26
  • @Pacerier, I have no idea. – gung Jan 10 '15 at 17:32
  • Why is there a spam post on the top of the screenshot of the home page? – dorukayhan Jul 15 '16 at 18:17

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

  • 4
    In fact, SO is a clone of Quick Answers :-) Quick Answers is launched in 2005, but Stack Overflow is launched in 2008. – ProgramFOX Oct 31 '13 at 8:56
  • @ProgramFOX You're right! I found questions posted in 2006 (example) but it seems the site wasn't widely used until second half of 2008. – Marek Grzenkowicz Oct 31 '13 at 10:35

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

  • I've added your plugin to the original post as after doing some searcher I think that it is probably one of the best solutions out there in the affordable price range for a small non-commercial project. – Marek Andreánsky Mar 18 '14 at 23:23

Squarespace has a QA site that looks very similar to SO's model

http://answers.squarespace.com/

  • 2
    Worth reading this. osqa.net is already discussed here, e.g. here. – Shadow Wizard Mar 20 '14 at 14:28
  • Ahh thanks for pointing that out @ShadowWizard. I should have checked that. I can delete my answer if necessary. – aug Mar 20 '14 at 16:53
  • As you wish, no harm in keeping it. :) – Shadow Wizard Mar 20 '14 at 18:40

http://devpytania.pl/ is a Polish version of Stack Overflow. It look like Stack Overflow a year or two years ago. The site looks like author doesn't update anything on the page. Even the years on foot are out date.

Arrayshift is a Drupal project that replicates a lot of the SO functionality. It's most recent release is based on Drupal version 6. Here is a screenprint of it:

enter image description here

  • Is it still in alpha? – Peter Mortensen Mar 28 '16 at 20:59
  • @Peter you can ask the project author, Pierre.Vriens he is now pingable here after editing. (@Pierre should work.) – Shadow Wizard Apr 20 '16 at 10:00

qato.com - 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 felt familiar.

  • 2
    Why did you not add to the main Answer? – Tshepang May 16 '11 at 12:30
  • 1
    @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 May 16 '11 at 14:27
  • Oh, I missed that. – Tshepang May 16 '11 at 15:01
  • Apparently this was merged into answerhub. – Abhimanyu Pallavi Sudhir Oct 2 '13 at 7:22

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

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

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

  • 1
    This one's been abandoned. It may (not) work. – StackExchange User Mar 2 '13 at 1:49

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

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

While digging for an answer to this question myself, I found that http://ask.sqlservercentral.com is not affiliated with Stack Exchange (but it does a fine job of ripping off the look and feel of the site):

Quote from Dumb question of the day

I can clarify that OSQA is a completely different Q&A community system than StackExchange. A month or two ago, Joel Spolsky announced that StackExchange was shifting direction and that the planned hosting model for StackExchange would be eliminated. We (the folks in the open source OSQA project) offered to help the soon-to-be homeless communities by helping them migrate to our system.

Red Gate contacted us about this offer, so we set up a demo site with the AskSSC community data. A while later they came back with some questions, which we answered, and they chose to go forward with the migration. We implemented the switchover this past Friday in order to have the weekend as a slow time to spot and fix any kinks in the live site.

There is no connection between StackExchange and OSQA. OSQA was originally based on a Chinese-language StackOverflow clone project called CNProg, but that original code has been almost completely eliminated and rearchitected. Going forward, I hope you'll see that OSQA is a verstile, reliable and useful system for hosting a Q&A community site like AskSSC. The StackExchange folks have made clear that their current version is a dead-end street and that no new development will be done on it. Their new business model doesn't accommodate sites like AskSSC, so staying on StackExchange really isn't a viable long-term option.

I'm sorry to learn that many in the AskSSC community were unaware this change was being considered, but I hope you'll all understand what took place. IMO, the Red Gate team was faced with a tough reality that was beyond their control. Having built a lovely community in conjunction with so many knowledgeable SQL Server experts, the rug was pulled out from under their feet. Granted, it would have been better if the migration had been more widely discussed and anticipated, and fewer community members would have been taken by surprise. Still, I hope the choice to use OSQA proves to be a good one and that the community will understand and support it.

FWIW, you should know that the OSQA developer team is deeply committed to helping this site and community thrive. OSQA is genuine open source software, and we are not being paid a penny for our work. We just want to continue evolving OSQA into a truly best-of-breed solution. We're probably insane, but we really do want to help.

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

  • Any idea what platform they are using (one of the open source clones, or something they wrote?) – Tim Post May 10 '12 at 4:16
  • @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 May 10 '12 at 4:19

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 better answers on Stack Overflow proper.

Aiqus has completely copied its design from Stack Exchange. Their community mods even have the diamond. The site is about artificial intelligence.

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

Apparently OpenStack has its own Ask OpenStack.

(I am not sure if this is based on AskBot or not, and if so, whether it deserves its own entry or not.)

Another clone is http://getthedata.org/. Note that the site is fairly old, and the SE system now has the Open Data site that serves the same function.

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