Mark Percival

Mark Percival

Investing Partner

Mark is a founding member and Investing Partner at Builders helping our portfolio companies execute faster, scale their technical teams, and building excellent engineering cultures that turn ideas into great products.

Before Builders, Mark was the co-founder and CTO of, where he grew the engineering team and scaled the product from prototype to production before being acquired by Yahoo. While at Yahoo, Mark worked as an Architect merging Tumblr’s platform with Yahoo Finance. He also designed the framework and lead the team that transitioned Yahoo’s international partners entirely to Tumblr.

Prior to, Mark was at Twitter, building their mobile platform and focusing on supporting their fast growing international user base. He also held the role of security liaison for the mobile platform due to his longstanding passion for encryption and web security.

He continues to be very involved in Open Source work, authoring and maintaining several popular security related libraries and products. When he’s not working directly on Open Source, he’s helping support it through various community efforts including organizing and giving talks at developer events.