Florian Deroo was working on multiplayer game servers at 15, with hundreds of people playing online at the same time. He would eventually move into machine learning research, but the appeal of building games never really left him. When Pure Interactive offered him the chance to help build a mobile poker platform from its earliest stages, he was back working on the kind of software that first sparked his interest in engineering.
Deroo joined Pure as a founding engineer and built the poker table that has since handled tens of millions of hands. The company develops Pure, a social gaming app that connects poker players online. Pure Interactive describes itself as a social gaming company, and unlike conventional poker operators, it does not take a rake from games between friends.
That approach appealed to Deroo because it put more emphasis on the experience of playing together. Keeping a game running smoothly was familiar territory, though real-money play introduced another level of responsibility.
“When there’s real money on the line, players notice everything on screen, and a card that shows up late or a chip stack that suddenly jumps is enough to make them wonder what just happened,” he said. Deroo has spent much of his time at Pure working on the systems that prevent those confusing moments.
Getting Every Phone on the Same Page
One difficulty with mobile multiplayer games is that devices rarely behave identically. At a Pure table, someone on an older iPhone might play against a friend on a newer model. Network connections vary, software versions differ, and the game still has to unfold consistently for everyone. A player shouldn’t have to think about any of that when deciding whether to call a bet.
Deroo’s work involves keeping the information displayed on each device synchronized with the server. The technical challenge extends to how quickly an action appears and how naturally the interface responds to what a player does.
Those details have become central to how he evaluates his own work. Pure was built as a native iOS experience, which means its responsiveness is being judged against the other mobile apps people use every day.
“Being mobile-only means players don’t compare us to other poker sites; they compare us to the best apps on their phone,” Deroo said. “It changed how I approach engineering: a feature isn’t done when it works, it’s done when it feels right in your hand.”
His education gave him a different set of technical experiences before he returned to gaming. Deroo studied engineering at ESIEE Paris and machine learning at UC San Diego, and conducted research involving aircraft engine data at Safran.
He brought that background and years of experience building multiplayer systems to Pure. The combination has been useful as the product has grown, particularly where large amounts of data need to be handled without slowing down the interface.
The Friends List Is an Engineering Problem
Pure’s social graph is one of the more demanding systems Deroo has worked on. Because the platform is organized around existing friendships, the app needs to connect player information with activity from games they’ve played. As the number of hands increases, retrieving that information quickly becomes more difficult.
Deroo gives the example of showing someone the best poker hands played by their friends. The feature sounds simple enough, but it can involve searching through tens of millions of recorded hands and finding the relevant results almost immediately.
“The hardest part is that the social graph never stops growing, and it touches everything, from your friends to every hand you’ve played,” he explained.
Maintaining that speed requires ongoing work on how the app retrieves and stores information. Deroo has also built shared components that handle connectivity and synchronization with the server, along with caching systems that help the app avoid fetching information it already has.
Those components were designed without tying them to poker. As Pure moves into additional games, other engineers can use the same underlying systems to create live features without rebuilding the technical foundations each time.
That has become a larger part of Deroo’s responsibility as the engineering team grows. He joined when Pure had very few players and could personally shape much of the original product. These days, he also reviews code written by other engineers and works on the systems they’ll depend on as they develop new features.
The change has brought him further into decisions about how the engineering team works, though he remains close to the product itself. He still has to think about what happens when two friends sit down at a table using different phones and expect the same game to appear.
Now, when another engineer starts building a multiplayer feature, Deroo wants the connection and synchronization problems to have already been solved well enough that they can concentrate on the game.
