Designer, writer, and developer. Principal Designer at GitHub. Advising and contracting with growing teams. Creator of Bootstrap. Previously at Twitter. Huge nerd.

Mark Otto is a designer, developer, and advisor in the San Francisco Bay Area. In 2007, he dropped out of college and moved to California to work at a design agency where he designed and developed dozens of projects for clients like Photobucket, Facebook, and his personal favorite, Britney Spears.

In 2008, he became a Product Designer (and later a Platform Designer for Web) at Twitter working on Promoted Tweets, Twitter.com during #NewNewTwitter, the Twitter Help Center, and several internal tools. He also created the popular open source front-end toolkit Bootstrap with @fat. In late 2012, he left to join GitHub as a Product Designer.

At GitHub, he worked on GitHub Enterprise, redesigned Issues, redesigned conversations, designed split diffs, shipped mobile web notifications, and iterated on GitHub.com’s overall aesthetic with ships like redesigned repositories, system fonts, dark header, and more.

From late 2015 to early 2017, he served as GitHub’s Director of Design, growing and managing a team of 30 designers, artists, and writers across Product and Marketing.

In 2017, the GitHub Design team split and he took on the Marketing half as Senior Director of Design. For over two years, he managed an extremely talented team of web designers, engineers, videographers, and artists that maintain GitHub’s brand, marketing sites, and creative campaigns.

In July 2019, he left management to become GitHub’s first Principal Designer & Brand Architect, focusing on designing, building, and shipping various brand projects, marketing sites, and other special projects. Some highlights include creative direction for The GitHub Shop, designing and developing special projects like GitHub’s intranet (aka The Hub), and writing and designing event keynotes like GitHub Universe and GitHub Satellite.

Since 2021, he’s been working with growing companies as an advisor and contractor on product design, marketing, narrative and storytelling, web design, and brand under the moniker Studio MDO. Clients have included Vercel, Zed, Dragonfly, and more.


  • Founder & Designer • Studio MDO
  • Principal Design & Brand Architect • GitHub
  • Senior Director of Design • GitHub
  • Director of Design • GitHub
  • Senior Product Designer • GitHub
  • Product Designer • Twitter
  • Designer • ZURB

About the site

This URL has been my online home for many years, manifesting at times as a blog or a portfolio until landing on this current single-column blog. Today it’s a bit of an outlet graveyard for my design-and development-related ramblings.

In case you were wondering, this site is:

You can find more about my macOS development setup in my config repo on GitHub. The design and code powering this site, however, is not available for re-use or purchase.

For comments or questions, feel free to ask me on GitHub, on Twitter, or, if you really hate me, via email at markdotto at gmail dot com.