Duolingo founder on the key to solving retention

July 21, 2025

“The way we solved [retention] was just through trial and error,” Duolingo founder Luis Von Ahn explains. “By now, some of us have some intuition about what is good for gamification, but the reality is that most of it is just trial and error.”

He continues:

“In the history of Duolingo, we have run 16,000 A/B tests. Each one of those is trying to figure out if we change these little things — “should this button be red or blue?” — to try to get you to come back. And its these 16,000 A/B tests that have made our retention outstanding. At this point our user engagement is starting to get comparable to social networks.”