Stack Overflow, part of Stack Exchange, is a free, community-driven, reputation-based Q & A site for computer programmers. No membership is required to ask questions or provide answers to questions by others.

OSQA is described as 'The free, open source Q&A system you've been waiting for. Your OSQA site is more than just an FAQ page, it full-featured Q&A community. Users earn points and badges for useful participation, and everyone in the community wins' and is a Q&A service in the education & reference category. There are more than 10 alternatives to OSQA for a variety of platforms, including Web-based, Self-Hosted, Android, Linux and Mac apps. The best OSQA alternative is Stack Overflow. It's not free, so if you're looking for a free alternative, you could try Stack Overflow or Stack Exchange. Other great apps like OSQA are Scoold, Question2Answer, Talkyard and AskBot.
Stack Overflow, part of Stack Exchange, is a free, community-driven, reputation-based Q & A site for computer programmers. No membership is required to ask questions or provide answers to questions by others.

Stack Exchange is a fast-growing network of 84 [and counting] question and answer sites on diverse topics from software programming to cooking to photography and gaming. We are an expert knowledge exchange: a place where physics researchers can ask each other about quantum...




Ever had a question? Ever had an answer? Ever had knowledge to share? We believe that coming together to inquire and learn, to share knowledge and to teach each other, makes the world a better place. We also believe that Q&A communities should be free from the politics and...




Scoold is inspired by StackOverflow and implements most of its features. You can ask and answer questions, upvote and downvote posts, earn badges and reputation. Each edit creates an new revision, making it easy to follow the history of edits. Scoold is optimized for the cloud.




A Q&A site helps an online community to share knowledge. No matter what your area of interest, people with questions can get super answers fast. Question2Answer is a popular Q&A solution.



Help each other — with the main features from StackOverflow, Discourse, Slack, Reddit, and Disqus.
Askbot is a Q&A system, like StackOverflow, Yahoo Answers and some others. Askbot is based on code of CNPROG, originally created by Mike Chen and Sailing Cai and some code written for OSQA.





Hypersay is a platform for interactive presentations that massively increase engagement. Keep your audience engaged with polls, questions, private notes and live slide sharing. Store, enrich & deliver presentations from your cloud.




Niko makes it incredibly easy for employees at all levels to share what is on their mind by letting them submit, vote on, and respond to questions, ideas and suggestions. It creates a different employee engagement experience.