Behind the product: Duolingo streaks | Jackson Shuttleworth (Group PM, Retention Team)

**Lenny Rachitsky** (0:00)
Duolingo is a $14 billion company. It's hitting all-time highs, too. It just keeps going up. I think it doubled in value in the past six months. Streaks is the most impactful feature.

**Jackson Shuttleworth** (0:08)
We have right now over 9 million users with a year plus streak. If you look at the numbers, I think it's been our biggest growth lover. What Duolingo really focuses on is, how do we help users build habits around language learning? Getting user come back the next day is the biggest problem to solve.

**Lenny Rachitsky** (0:24)
Let's get into the mother load of learnings from the journey of streaks, talk about the key lessons, insights, and also wrong turns along the way.

**Jackson Shuttleworth** (0:30)
I'd say test everything. We've run in the last four years over 600 experiments on the street. So every other day, we've actually set up really good infrastructure for copy testing. We used to say, continue our standard CTAs, continue. And we changed that to commit to my goal. And it was a massive win.

**Lenny Rachitsky** (0:48)
There's so much human psychology that you all learn through all these experiments of just how to motivate people, what motivates, what demotivates.

**Jackson Shuttleworth** (0:55)
Let's say that you played a mobile game, or that you've done it for 3,000 days in a row. I don't know, maybe that hits a little bit different than you've learned Spanish for 3,000 days in a row.

**Lenny Rachitsky** (1:07)
Today, my guest is Jackson Shuttleworth. Jackson is a group product manager at Duolingo, leading the retention team. This is a different kind of episode that I'm experimenting with, where we spent the entire conversation focused on the journey and lessons of a single feature. In this case, Duolingo Streaks. Duolingo is a $14 billion business. Just over the past 6 months, they doubled in value. They're hitting all-time highs in usage and market cap. They're also one of the very few successful and also the single biggest consumer app business in the world. And as you'll hear from Jackson, the Streaks feature is the single most impactful feature that most contributed to this growth and success. In other words, you could argue this one feature created billions of dollars of value, which to me means it is worth studying in depth. In our conversation, Jackson shares the history of the Streaks feature, all the biggest wins and wrong turns they've taken along the way, what he and his team have learned about what works and doesn't work with a Streaks mechanic, and also how they set up their teams to operate in a way that allows them to run over 600 experiments on this product and continue to find big wins. I hope to do more episodes like this on features and products that you'd love to hear more about. So, leave a comment either on YouTube or on Substack and tell me which product or feature you'd love to see me cover. And if you enjoy this podcast, don't forget to subscribe and follow it in your favorite podcasting app or YouTube. It's the best way to avoid missing future episodes and it helps the podcast tremendously. With that, I bring you Jackson Shuttleworth.
Jackson, thank you so much for being here and welcome to the podcast.

**Jackson Shuttleworth** (2:48)
Yeah, thank you. Long time listener, first time caller.

**Lenny Rachitsky** (2:50)
So I appreciate it. So this is going to be a really interesting conversation. I've never done an episode like this before, where we basically spent like an hour, an hour and a half going into one feature of one product. But this is a very special feature. It's a very special product. Have you ever spent like an hour, an hour and a half just talking about this one feature with anyone?

**Jackson Shuttleworth** (3:13)
Well, internally, so when we onboard new folks to the team, I actually just did this with somebody that joined the team recently, where we spent, and I was like, hey, let's spend an hour just talking about this streak. We got through an hour and I got through about 30 percent of what I wanted to share. There's just so much, we'll talk about this, but there's so much that we've learned over the years. But never anything externally like this. I think we've shared bits and pieces of learnings, but this will be like the mother load of learnings, hopefully. There you go, of how Duolingo built the streets.

**Lenny Rachitsky** (3:42)
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