At age 23, Mitchell Hashimoto built an open-source tool and turned it into HashiCorp. Here's how he became a billionaire even after leaving the C-suite.

Mitchell Hashimoto built the foundation of a multibillion-dollar company as a passion project.

The then-23-year-old created an open-source software development tool called Vagrant, which became one of the cornerstones for HashiCorp, the company he cofounded with Armon Dadgar.

HashiCorp now makes a suite of subscription-based tools for companies and other organizations to manage their cloud computing systems. Hashimoto, after whom the company is named, has worn several hats as a cofounder: from CEO to co-CTO to individual contributor. Through it all, he's always been a coder at heart.

"When I got back to working on an engineering problem hands-on, it was my favorite thing I did over and over," Hashimoto told Insider's Rosalie Chan in July about his decision to step down from the C-suite.

That's been an advantage for HashiCorp, which went public earlier this month. Glenn Solomon, a partner at GGV Capital, which invested in the company, told Insider he believes that startups building tools that cater to developers will be key to unlocking the next $1 trillion of value in the tech industry.

HashiCorp has made a significant contribution toward that total with its public debut. The company's market cap is more than $14 billion.

Hashimoto, according to a filing with the U.S. Securities and Exchange Commission, owns a more than 8% stake in the company he cofounded. That's now worth more than $1 billion.

Here's how he became a startup billionaire.

Mitchell Hashimoto grew up loving to code. By his early twenties, he'd already come up with two money-making ideas.

As a teenager, he ran a business where for $25 a month, customers could find cheat codes for popular video games, including the "Neopets" franchise.

Neopets ended up sending Hashimoto a cease-and-desist letter, he told Insider's Julie Bort in 2014.

When he was a student at the University of Washington, Hashimoto wrote software that would automatically register students for classes, and they paid him for the privilege.

At the University of Washington, Hashimoto met Armon Dadgar, who would become HashiCorp's cofounder and CTO.

Hashimoto and Dadgar began working on open-source software projects together. One of them, Vagrant, became quite popular.

As HashiCorp states in its origin story on its website, the two wanted to make then-emerging cloud computing technologies available to scientists.

In 2012, Hashimoto launched HashiCorp to turn that technology into a business. Dadgar joined him as the company's cofounder the next year.

In 2014, HashiCorp raised $10.2 million in Series A funding from Mayfield, GGV Capital, and True Ventures. By that time, it counted the BBC, Mozilla, and Nokia as customers.

Over the next few years, HashiCorp released other products for organizations to manage their cloud operations, including Consul, Terraform, Vault, and Nomad.

For the first few years, Hashimoto served as HashiCorp's CEO. But in 2016, he stepped down, and the company hired Dave McJannet to fill the role.

"With technical strategy, I can tell you what we're building five years from now. With business strategy, I struggle a bit more," Hashimoto told Insider's Rosalie Chan in 2018.

By that time, the company had grown to more than 300 employees. Glenn Solomon of GGV Capital, one of HashiCorp's investors, told Insider Hashimoto's knack for finding skilled executives was one of his key strengths, alongside his technical prowess.

After stepping down as CEO, Hashimoto served as co-CTO alongside Dadgar for a few years. HashiCorp continued releasing new open-source projects, including Boundary and Waypoint.

By 2021, HashiCorp had raised nearly $350 million from investors such as Redpoint Ventures, Bessemer Venture Partners, IVP, and T. Rowe Price.

At the same time, Hashimoto was considering stepping back from the C-suite altogether, to spend more time on programming and less on travel and customer meetings.

In July, he announced he was stepping down as co-CTO to become an individual contributor at HashiCorp. He now reports to Dadgar, the company's sole CTO.

Even so, he still has a sizable stake in the company, which is worth more than $1 billion after its public debut in December.

According to HashiCorp's S-1 filing with the SEC, Hashimoto has an 8.4% stake, while Dadgar, the company's CTO, has a 10.5% stake.