The GitHub Mafia: Cultivating a New Wave of Tech Founders
GitHub didn’t just change the way developers share and manage code; it also became a place for a new generation of founders.
Let’s rewind to 2010. GitHub was a scrappy startup with just a handful of employees when Zach Holman joined as its ninth hire. The company had already started reshaping software development, but internally, it was unlike any other tech company.
Enter Zach Holman, a Ruby enthusiast drawn to GitHub’s open-source ethos and flat structure.
"I joined in February 2010 as employee number nine," Zach recalls. "I’d been following the founders’ blogs in the Ruby community, and the company’s openness really resonated with me."
GitHub’s early days weren’t just about building a product—they were about building a culture. A culture that gave employees freedom, ownership, and a mandate to experiment.
Since its 2008 founding by Tom Preston-Werner, Chris Wanstrath, P. J. Hyett, and Scott Chacon, GitHub has grown into the world’s go-to platform for open-source projects, enterprise collaborations, and individual developers alike.
GitHub alumni have built startups that span developer tools, AI, fintech, and beyond. This growing “mafia” includes notable names like Jason Warner (Poolside), Chris Jennings (Sentry), and Jessie Frazelle (Oxide Computer Company), each drawing from their GitHub roots to build new ventures.
GitHub's Alumni
Key Stats:
- 64 companies launched by alumni
- $1.4 billion in funding raised
- Notable companies include Poolside, Sentry, and Oxide Computer Company
Zero to 300: Scaling Fast
When Zach joined GitHub, the company was still small, but growth came quickly.
"When I left, the company had grown to around 250–300 employees," he shares. "It was a massive leap from where we started. That kind of growth changes the culture in ways you can’t always anticipate."
But while the team scaled, GitHub’s builder mindset remained intact.
"There was a strong interest in hiring people who knew how to make things happen independently," Zach says. "Kyle Neath, our lead designer, always said he wanted to hire people who ‘knew how to make money on the internet.’ That mindset fostered creativity."
Side Projects Were Encouraged
At GitHub, side projects weren’t just tolerated—they were encouraged. It was a place where employees could experiment, learn, and bring ideas to life.
"They didn’t mind side projects as long as they didn’t interfere with GitHub work," Zach explains. "It was very much a ‘builder’ culture. Contributing to open source was part of the DNA, and that mindset translated into everything we did."
GitHub even floated the idea of funding internal startups—a concept that never materialized but showed how deeply the founders valued innovation.
A Flat Structure & Ownership
What made GitHub unique was its flat structure and emphasis on ownership. For years, the company operated without managers, allowing employees to fully own their roles.
"One of the things that stood out was how invested everyone felt in their work," Zach says. "It wasn’t just a job—it was a place where you could take real responsibility and shape the outcome."
This autonomy became the foundation for many GitHub alumni who went on to launch their own companies.
The GitHub Mafia Today
Fast forward to today, and the GitHub Mafia is making waves across tech. Alumni like Ashley Smith and John Britton have transitioned to venture capital, investing in areas they’re passionate about, like developer tools and SaaS. Others, like Zach, are building startups and sharing their knowledge with the next generation of founders.
"We even have a Slack group for ex-GitHub employees," Zach shares. "It’s a tight-knit community where people share advice, discuss investing, and help each other out."
Here's what some of GitHub's alumni-turned-founders are up to:
- Jason Warner - Founder of Poolside
- GitHub Role: CTO
- Capital Raised: $526M
- Investors: Bain Capital Ventures
- Stage: Private Equity
- Poolside is an AI platform providing foundation concepts and infrastructure.
- Chris Jennings - Founder of Sentry
- GitHub Role: Product Designer
- Capital Raised: $217M
- Investors: Accel
- Stage: Series E
- Sentry develops an application monitoring platform to optimize code performance.
- Conrad Wilkinson Schwarz - Founder of Baubap
- GitHub Role: Projects and Tutorials
- Capital Raised: $143.6M
- Investors: Y Combinator
- Stage: Debt Financing
- Baubap is a fintech platform offering instant, paperless personal loans in Mexico, aiming to improve financial inclusion.
- Jessie Frazelle - Founder of Oxide Computer Company
- GitHub Role: Staff Software Engineer
- Capital Raised: $94M
- Investors: Eclipse Ventures
- Stage: Series A
- Oxide Computer Company designs high-performance server racks with cloud-like efficiency for on-premises use.
- Max Stoiber - Founder of Stellate
- GitHub Role: Software Engineer
- Capital Raised: $30M
- Investors: Tiger Global Management
- Stage: Series A
- Stellate provides cloud-based solutions to enhance GraphQL API performance and security.
- Connor Sears & Scott Goldman - Founders of Rewatch
- GitHub Role: Senior Director of Product Design; Principal Engineer
- Capital Raised: $22M
- Investors: Haystack
- Stage: Series A
- Rewatch offers a secure video hub for teams, making recorded meetings searchable and accessible.
- Phillip LeBlanc - Founder of Spice AI
- GitHub Role: Senior Software Engineering Manager
- Capital Raised: $14.6M
- Investors: Basis Set Ventures
- Stage: Seed
- Spice AI simplifies massive data infrastructure, enabling developers to build next-gen AI apps.
- Marcel Käding - Founder of Superlist
- GitHub Role: Senior Program Manager
- Capital Raised: $14.6M (€13.5M)
- Investors: Cherry Ventures
- Stage: Seed
- Superlist is a task and project management platform designed to enhance team collaboration.
Lessons from GitHub
Zach’s time at GitHub wasn’t just about building software—it was about learning what it takes to scale a company, build a team, and foster a culture of innovation.
So, what’s his advice for aspiring founders?
"Leverage your network," he says. "Founders often don’t use their angel investors enough. And, especially in today’s environment, focus on revenue. It’s not just about building a great product—it’s about creating a sustainable business."
Looking Ahead
The GitHub Mafia is just getting started. With a strong foundation of collaboration, creativity, and community, its alumni are poised to shape the future of tech for years to come.
For Zach, the journey from GitHub to founder and angel investor has been one of learning, adapting, and giving back.
As he puts it, "GitHub was a place where builders thrived, and that legacy is still inspiring people today."
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