SAN FRANCISCO — For much of the first three weeks of Pokemon Go mania last summer, Niantic chief technology officer Phil Keslin was trapped in the office with his engineers, tirelessly trying to keep its servers from crashing.

They faced one of their biggest challenges preparing for a community-formed “Pokemon Go Crawl” in San Francisco. More than 8,500 people signed up for the afternoon gathering, and Niantic scrambled after its servers crashed earlier that morning. If they crashed again amid the crawl, Keslin joked, there would have been “torches in our offices” from angry Pokemon Go fans.

But the servers held. The crawl moved without a hitch. The success allowed Keslin and his team to leave their San Francisco office to get some fresh air and catch the tail end of the mass event.

“For a team that has been bottled up inside, it was moving to see and motivated everyone on the team,” Keslin said.

That seems like light years ago for Keslin and Pokemon Go, which in February became the fastest mobile game to reach $1 billion in revenue, according to app analytics firm Sensor Tower. Niantic on Saturday planned to celebrate Pokemon Go’s one year anniversary with a festival in Chicago. Up to 20,000 people were expected to show up, catch Pokemon and play against each other.

Keslin, a Texas native, sat down with this news organization recently to talk about how his rural upbringing influenced the augmented reality mobile game and what lies ahead for Pokemon Go, which at its peak was played by 50 million users every day. This interview has been edited for clarity and length.

Q: What do you do as CTO of Niantic? What does that job entail?

A: I manage the engineering team. I look for future technology that can enhance the games we produce. One of our company’s missions is “adventure on foot with others.” Building experience that can motivate people to go outside and have adventures and do that with others are the things we are going to build.

Q: Why is outdoors such a big component to Niantic’s mission?

A: For me, when I was growing up as a kid, I was kicked out of the house every day. I got out of bed, and mom kicked us out and told us not to come back until dinner. We just enjoyed playing outside. My mother’s family grew up on the farm so running through the trees and the forest was like entering a different world. Giving that to my kids is something I really wanted to do.

Q: When did you first encounter Pokemon?

A:I have three kids. My son, when he was five — 17 years ago — he had Pokemon video games and playing cards. So I’ve seen Pokemon for a while. I’ve seen Pokemon come and go in the house. But it was always something they cherished.

Q: Your first few weeks of Pokemon Go is the stuff of Silicon Valley folklore now. Would you have done anything differently?

A: I don’t think there was anything we could do differently. We thought we were pretty aggressive in planning our expectations. We had a chart I put together on what we expected and our worst-case scenario was we took one of the most popular mobile games at its peak as the number we would reach. And then we multiplied that by 5. But we ended up with 50 times that.

Q: The amount of daily users for Pokemon Go has dropped from 50 million at its peak to around 5 million now. Some point to that as a sign of decline. What are your thoughts?

A: We have an individual in our office who has this perfect quote: “we have gone from a cultural phenomenon to a hit game.” Sure, it was a huge viral success. Nobody imagined we would get that big. But where we are today, we are larger than other big games. If we did not have that huge viral surge, people would be talking about us as a big, big game, not a smash hit on the decline.

Q: I want to turn the topic to augmented reality. When I was doing a story on Apple’s ARKit, developers repeatedly point to Niantic as the company to keep an eye out for. What are your thoughts on ARKit?

A: I think it’s a good first step. They have the benefit of millions and millions of devices which will be launched as soon as they roll out. Because of that, they’ll get a lot of penetration immediately. It does a reasonably good job. It does better than we do today, which is gyro-synchronization.

Q: Does Niantic use ARKit?

A: We use it. We already demonstrated how we might use ARKit. The biggest one we did was the playground mode where you can pull out six of your Pokemon and stick them in a playground in a real life setting and walk around them and see how big they are. You don’t get a good feeling for how big a Charizard gets to be.

Q: Do you feel like Niantic are pioneers in AR in any way or fashion?

A: I don’t know about pioneers. We just use the technology to enhance our story of Pokemon existing in the real world and being able to locate one in real life and capture them and sharing that experience with our friends. We will continue to use AR if it allows us to foster our story.

Q: Your Pokemon Go Festival is wildly popular, with tickets selling out in minutes and getting resold at hundreds more dollars. How did that come to be and why is it so popular?

A: It grew out of Ingress (Niantic’s earlier augmented reality mobile game), and Ingress has a long history of these kinds of events that have grown steadily over time. At first, we had tens of people show up at the Cahokia Mounds just outside St. Louis. In a matter of years, it turned to thousands of people. Ingress is a significantly smaller game than Pokemon Go, so we knew (Pokemon Go Festival) would probably be big. The hardest part of planning that kind of a party was planning the logistics so we found a place where we can hold as many people as we could.

Q: Along with the festival, does Niantic have any cool additions to Pokemon Go?

A: We added new gyms and new generations of Pokemon to play with. We recently added raids and new gym features and co-op gameplay element. We hoped to do it sooner, but the craziness of being a cultural phenomenon prevented us from releasing this earlier.

Phil Keslin

Age: 53

Position: Chief Technology Officer, Niantic, Inc.

Hometown: Garland, Texas

Education: University of Texas-Austin (B.A., Computer Science), Southern Methodist University (MBA)

Previous employers: Google, Nvidia, Keyhole, SGI, E-Systems, IBM

Family: Wife and 3 children

Five facts about Phil Keslin