# Michael Hartl
Building since 2005. Not reviewed by Michael.
Page: https://mrrmaker.com/@michaelhartl
Rails Tutorial (2009), Tau Day (2010); sold Learn Enough (2022)
In their words: "You might know me as the founder of Tau Day and author of The Tau Manifesto , as the creator of the Ruby on Rails Tutorial , or as cofounder and principal author at Learn Enough" (michaelhartl.com)

## Numbers
- Products: 7
- Building since: 2005

## Products
- Softcover (2014 →): running
- Tau Day (2010 →): running
- Learn Enough (2015 – 2022): sold, sold to an undisclosed buyer
- Ruby on Rails Tutorial (2009 – 2022): sold, sold to an undisclosed buyer
- Insoshi (2008 – 2009): shut down
- Quark Sports (2005): shut down
- RailsSpace: dates not stated in any source

## Timeline
- Jun 2025: Tau Day: Tau featured in Apple's iOS, Google's official calculator and the Python programming language; Tau Day featured in Science News and The Wall Street Journal [stated]
- by Aug 2022: Sold Ruby on Rails Tutorial to an undisclosed buyer [stated]
- by Aug 2022: Sold Learn Enough to an undisclosed buyer [stated]
- Aug 2022: Ruby on Rails Tutorial: Produced seven editions of the Ruby on Rails Tutorial [stated]
- Jan 2016: On Software Engineering Daily, Learning Rails with Michael Hartl [stated]
- 2015: Launched Learn Enough [stated]
- Mar 2014: Launched Softcover [stated]
- Mar 2011: On Programming Zen interview about the Rails 3 Tutorial [stated]
- Feb 2011: On coderpath podcast, about the origins of the Rails Tutorial [stated]
- Jan 2011: On Teach Me To Code, episode 46 [stated]
- Jun 2010: Launched Tau Day [stated]
- 2009: Launched Ruby on Rails Tutorial [stated]
- Apr 2008: Launched Insoshi [verified]
- 2008: Joined Y Combinator (Winter 2008) to work on Insoshi [stated]

## How sure
8 verified by someone other than Michael, 42 stated by Michael in public, 0 outdated. Read on 11 Oct 2026.

## Sources
- Michael Hartl, michaelhartl.com: https://michaelhartl.com
- About Michael Hartl | Michael Hartl, michaelhartl.com: https://michaelhartl.com/about
- github.com: https://api.github.com/users/mhartl
- Learn Enough and the Rails Tutorial have been acquired, news.learnenough.com: https://news.learnenough.com/big-news-about-learn-enough
- Softcover – A publishing platform based on the Rails Tutorial, news.learnenough.com: https://news.learnenough.com/softcover_launch
- Tau Day, tauday.com: https://tauday.com
- Tau Day 2025, michaelhartl.com: https://www.michaelhartl.com/tau-day-2025
- State of the Tau 2024, michaelhartl.com: https://www.michaelhartl.com/state-of-the-tau-2024
- Softcover.io, softcover.io: https://www.softcover.io/about
- Start learning to code, learnenough.com: https://www.learnenough.com
- Social Networking Goes Open Source With Insoshi, techcrunch.com: https://techcrunch.com/2008/04/29/social-networking-goes-open-source-with-insoshi
- Insoshi: Open-Source Rails-based Social Networking Platform, rubyinside.com: https://rubyinside.com/insoshi-open-source-rails-based-social-networking-platform-878.html
- Insoshi, ycombinator.com: https://www.ycombinator.com/companies/insoshi
- Interview with Michael Hartl, author of the Rails 3 Tutorial, programmingzen.com: https://programmingzen.com/interview-with-michael-hartl-author-of-the-rails-3-tutorial/
- Learning Rails with Michael Hartl, softwareengineeringdaily.com: https://softwareengineeringdaily.com/podcasts/learning-rails-with-michael-hartl/
- Episode 46: TMTC 45 – Michael Hartl – Rails Tutorial, topenddevs.com: https://topenddevs.com/podcasts/teach-me-to-code/episode-46-tmtc-45-michael-hartl-rails-tutorial
- 024 - Michael Hartl, Author of The Ruby on Rails Tutorial, codewithjason.com: https://www.codewithjason.com/podcast/9478291-024-michael-hartl-author-of-the-ruby-on-rails-tutorial
- coderpath interview about the Rails Tutorial project, news.learnenough.com: https://news.learnenough.com/coderpath-interview-about-the-rails-tutorial-project
- Site checks on 2026-10-11, MRRMaker: https://mrrmaker.com/how-it-works#checks

Labels: "verified" means confirmed by someone other than the founder; "stated" means the founder said it in public. Method: https://mrrmaker.com/how-it-works