How Phil Crosby (B.S. ’06, computer science; B.A. ’06, economics) made his lifelong tech startup dream a reality as co-founder of the mobile advertising platform Liftoff.
In June 2026, California tech company Liftoff went public on the Nasdaq Stock Market. For the company, it was a milestone 14 years in the making. For Phil Crosby (B.S. ’06, computer science; B.A. ’06, economics), the company’s co-founder, the adventure started way before that.
“In middle school and in high school, I always knew I wanted to do a startup, so starting the company came naturally from my childhood and my early work experience at the University of Maryland. I just couldn't imagine life without it,” Crosby said. “What I did not imagine was that it would come this far, that this startup we built would grow to be hundreds of people across the world, servicing so many customers that we could go public, and public investors would care about us. It's awesome, but surreal.”
Launched in 2012 by Crosby and co-founders Mark Ellis and Harry Robertson as what Ellis called a “small startup with a big vision,” Liftoff is now a multi-million-dollar global company, making a game-changing impact in the world of mobile advertising with its artificial intelligence-enabled growth acceleration and marketing platform Cortex. The platform helps app developers target new users and optimize their engagement, growth and revenue.
“What we built is a system that uses machine learning and AI to predict what apps someone might be interested in, and then we can show advertisements when they're using other apps, and tell them, ‘Hey, did you know about this app? You should try it—click here to install,’” Crosby explained. “We’ve been able to reliably build on the foundation we started with, and as the performance advantages of our system have compounded, we’ve been able to leave most competitors behind. I'm amazed and thankful for what we’ve accomplished.”
Self-taught and always curious
Growing up in Montgomery County, Maryland, Crosby got his first computer—a 386 PC—in elementary school. Always curious, he taught himself to program and build websites by middle school.
“I made a Calvin and Hobbes fan website, a Street Fighter website, and eventually, I had a graphic design website, and people started contacting me to make logos and websites for them. They were actually paying me, a middle schooler, to do this stuff,” he recalled. “I realized then that I could make money from using computers and building these skills. It was clear even in middle school: I'm going to study computer science, for sure.”
Even then, Crosby was intrigued and impressed by the power of technology.
“In high school, everybody I knew was using Microsoft and their products for work, instant messaging, and playing games,” he said. “I thought, okay, cool, that's how you use technology to affect everybody. It changed the world, and I wanted to do that.”
In the early 2000s, as a computer science and economics dual-degree student at the University of Maryland, Crosby dug deeper into the challenges of software engineering, design and data visualization.
“The depth of the education I got at UMD was very helpful, and I think the most important class I took was human-computer interaction. It was my first time learning from somebody about how software should make you feel, how a human should understand it – not the visual design, but the interaction design – how the workflow is supported by the software. I also learned data visualization—how to take a large dataset and present it so you can derive insights from it,” Crosby explained.
Crosby and his roommate Michael Quinn (B.S. ’06, computer science) were in the data visualization class together.
“We’d stay up all night doing the homework—and now, he’s one of the early employees at Liftoff, can you believe it? The community at UMD was really important for me,” Crosby reflected.
Impactful undergraduate internships at Microsoft and IBM reinforced Crosby’s plans.
“Those internships were pivotal for me to see my career, what it could be and what it takes to be a good software engineer,” Crosby said. “I saw what big company life is like, which helped reinforce that I definitely wanted to do a startup; something small where I can have more influence and impact.”
On to Silicon Valley
Anxious to engage with more tech innovation, Crosby headed to California after graduation.
“I moved to Silicon Valley with just a suitcase and no money, and a tenuous agreement to do some consulting work with a small lab, but, oh, it was glorious,” Crosby said. “All these internet startups were blowing up, and I was in this little office doing contract coding work right next to Facebook's headquarters. It was a really cool time.”
In 2008, Crosby joined Ooyala, an online video technology innovator in the heart of Silicon Valley that supported big media companies like NBC and ESPN. There, he leveraged his user experience and data science skill set and expanded his software engineering skills to develop new products, including the frontend system for a Flash player that was used by millions of people.
But he hadn’t forgotten his plan to launch a startup. In 2011, a company hackathon became the catalyst.
“Harry, Mark and I worked at Ooyala together, and that year, the company held this hackathon where the challenge is to build a new idea that's related to the company. We spent two nights, all night, coding in the office—and we won!” Crosby recalled. “Afterward, it was clear. I said, ‘Guys, we have to start a company together!’”
At that time, in the tech world, countless apps were launching, and app stores were booming. But Crosby and his colleagues could see something was missing: a way to connect these apps to the people who would want to use them. That problem launched Liftoff.
“Apps were being developed like crazy back then, but we noticed that even if you had a marketing budget, that didn't mean you could reliably get an audience for your app. For larger companies like Amazon or Facebook, and the mid-sized companies in between, transitioning their products from the web to mobile apps was really difficult,” Crosby explained. “If you make a hit app, how will people come? That’s the problem we wanted to solve.”
So, Crosby and his co-founders tapped into their combined experience—from building mobile apps and video delivery systems to analytics and monetization—to find the answer. And through years of problem-solving research, engineering and innovation, the Liftoff team created one of the world’s biggest independent mobile app growth platforms, supporting more than 167,000 apps in 200 countries.
And now, the ‘small startup with a big vision’ isn’t so small anymore.
“We started with the three of us, and Liftoff was fewer than 20 people for the first three years or so, and those days were so fun,” Crosby said. “Today, we are over 650 people, and we have offices around the globe. It’s still hard to believe sometimes.”
For Crosby, the startup experience has gone far beyond anything his middle-school self could have hoped for—and the adventure continues.
“I think it's one of life's greatest adventures to be able to start a company, because you have the autonomy to make choices, and the success or failure is on you. And it's a very social and connecting activity. You hire the team that you want to work with and spend all your time with them trying to overcome difficulties and adversity, and that bonds you—like at university, the experiences really bond you together,” Crosby said. “So I think it's one of the great things that someone can do with their life. I've really enjoyed it, and I think Liftoff will keep on rocking from here.”
