# Duolingo: how they nailed their product and became the #1 education app

> Learn how Duolingo builds on its mission, design and data to craft their product to perfection. Includes examples of their most notable A/B tests.

Source: https://blog.salesflare.com/duolingo-iconic-product-e3df449017df
Language: en
Published: 2018-08-02  ·  Updated: 2026-06-29

---
<!-- QUARANTINED — not auto-converted.
     Medium import: .graf markup (one of the 50 identified in FINDINGS)
     Body below is the chrome-stripped source HTML, awaiting hand conversion. -->

<header></header>
<h2>Iconic Products episode 008</h2>

<figure id="08bf" class="graf graf--figure graf-after--h4">
<div class="aspectRatioPlaceholder is-locked">
<p><img decoding="async" class="graf-image alignnone" src="https://cdn-images-1.medium.com/max/800/0*Sv34Fa2E0360PEhZ.jpg" alt="duolingo logo" width="796" height="419"></p>
</div>
</figure>
<p id="b135" class="graf graf--p graf-after--figure">Every single morning, before heading to <a class="markup--anchor markup--p-anchor" href="https://salesflare.com">Salesflare</a>, I shower, get dressed, <em class="markup--em markup--p-em">do my daily Duolingo courses</em>, eat breakfast and walk the dog.</p>
<p id="ca1a" class="graf graf--p graf-after--p">Yup, <strong class="markup--strong markup--p-strong">Duolingo</strong> is part of my daily routine. And it is for (probably about 10–20) millions of other daily active users.</p>
<p id="c427" class="graf graf--p graf-after--p">It’s a very impressive feat for an app to pull this off. Especially if the app is all about learning a foreign language. That doesn’t sound too exciting, right? 😏</p>
<p id="f59e" class="graf graf--p graf-after--p">Duolingo actually <strong class="markup--strong markup--p-strong">makes language learning fun</strong>, and maybe even slightly <strong class="markup--strong markup--p-strong">addictive</strong>. 😬</p>
<p id="4b5a" class="graf graf--p graf-after--p">Is that even possible? How is that possible?</p>
<p class="graf graf--p graf-after--figure graf--trailing">We’ll get into the <strong class="markup--strong markup--p-strong">how</strong> after exploring the <strong class="markup--strong markup--p-strong">why.</strong> 👇</p>

<hr class="section-divider">

<h2 id="59ab" class="graf graf--h3 graf--leading">Duolingo’s mission: making language education personalized, fun and universally accessible</h2>
<p id="2fc8" class="graf graf--p graf-after--h3">Faced by the <strong class="markup--strong markup--p-strong">inequalities</strong> of traditional education, especially in his hometown of Guatemala city, Duolingo’s co-founder Luis von Ahn, felt like something needed a change. 🧐</p>
<p id="7c98" class="graf graf--p graf-after--p">He figured that, particularly in poorer countries, <strong class="markup--strong markup--p-strong">education was broken</strong>. People who have money can get top education, while people who don’t have money barely know how to read and write. And because of that, don’t make any money. A vicious circle. 😔</p>
<p id="3957" class="graf graf--p graf-after--p">Luis saw there was language learning software out there, like Rosetta Stone, but it was prohibitively expensive, and it therefore didn’t help to close the education gap.</p>
<p id="87cd" class="graf graf--p graf-after--p">That’s when Duolingo was born, promising <strong class="markup--strong markup--p-strong">free language learning</strong> to everyone. Accessible to everyone who wants to learn. ✨</p>

<figure id="1bb4" class="graf graf--figure graf--layoutOutsetCenter graf-after--p">
<div class="aspectRatioPlaceholder is-locked">
<p><img decoding="async" class="graf-image alignnone" src="https://cdn-images-1.medium.com/max/1000/1*WPf_4tpQiJF7Rv6rwlQUMA.png" alt="duolingo CTA" width="1000" height="370"></p>
</div>
</figure>

<p id="f683" class="graf graf--p graf-after--figure">Based on its mission, Duolingo has been attracting users, employees and investors ever since.</p>
<p id="a309" class="graf graf--p graf-after--p">Of course, to survive, Duolingo had to <strong class="markup--strong markup--p-strong">make money</strong> in some place. They chose to do this based on ads, monthly subscriptions that remove the ads, <a href="https://userpilot.com/blog/in-app-marketing-guide-for-product-marketers/">in-app</a> purchases and the Duolingo English Test.</p>
<p id="ffa5" class="graf graf--p graf-after--p">And besides making it universally accessible, they also focused on making the learning personalized and fun. 😍</p>
<p id="5729" class="graf graf--p graf-after--p">They believed that software was perfectly fit to offer a <strong class="markup--strong markup--p-strong">personalized</strong> experience to every single language learner.</p>
<p id="f618" class="graf graf--p graf-after--p graf--trailing">And that language learning should be less boring and more like a <strong class="markup--strong markup--p-strong">fun</strong> game. Who’d want to come back to a language learning app otherwise? 😉</p>

<hr class="section-divider">

<h2 id="cca3" class="graf graf--h3 graf--leading">A product organization, focused on design and&nbsp;data</h2>
<p id="e632" class="graf graf--p graf-after--h3">Universally accessible, personalized and fun. Sounds great. 👍</p>
<p id="5185" class="graf graf--p graf-after--p">Now how do you make that happen?</p>
<p id="3627" class="graf graf--p graf-after--p">Duolingo’s strategy is to relentlessly improve its<strong class="markup--strong markup--p-strong"> product design</strong> to incite the <strong class="markup--strong markup--p-strong">right</strong><strong class="markup--strong markup--p-strong"> user behavior</strong> based on <strong class="markup--strong markup--p-strong">data</strong>. 👈</p>
<p id="54f5" class="graf graf--p graf-after--p">And they mean it. More than 3/4 of Duolingo’s team works on engineering, design, product or research.</p>
<figure id="4613" class="graf graf--figure graf-after--p">
<div class="aspectRatioPlaceholder is-locked">
<p><img decoding="async" class="graf-image alignnone" src="https://cdn-images-1.medium.com/max/800/1*qi9Zp7GYyo_rmmEmdC8KQg.png" alt="chart of different jobs, one goal" width="800" height="437"></p>
</div>
</figure>
<p id="0ed0" class="graf graf--p graf-after--figure">This is in stark contrast with the other big language learning software player out there: Rosetta Stone. Only slightly more than 1/4 of its team works in these same departments (based on LinkedIn Premium data).</p>
<p id="e295" class="graf graf--p graf-after--p">It’s the classic battle: <strong class="markup--strong markup--p-strong">product organization</strong> v.s. marketing-sales organization.</p>
<p id="70f0" class="graf graf--p graf-after--p">And if you investigate Rosetta Stone v.s. Duolingo growth, Duolingo’s product strategy proves to be superior. 💪</p>
<p id="a438" class="graf graf--p graf-after--p">They get more interest in searches according to Google.</p>
<figure id="52be" class="graf graf--figure graf-after--p">
<div class="aspectRatioPlaceholder is-locked">
<p><img decoding="async" class="graf-image alignnone" src="https://cdn-images-1.medium.com/max/800/1*lvk4bt5aExncJ9-2ClNuxQ.png" alt="comparing duolingo to rosetta stone in interest over time" width="800" height="423"></p>
</div><figcaption class="imageCaption">Interest shown on Google search for Duolingo and Rosetta&nbsp;Stone.</figcaption></figure>
<p id="bacf" class="graf graf--p graf-after--figure">And grow their company at a much higher rate according to LinkedIn.</p>
<figure id="097b" class="graf graf--figure graf-after--p">
<div class="aspectRatioPlaceholder is-locked">
<p><img decoding="async" class="graf-image alignnone" src="https://cdn-images-1.medium.com/max/800/1*GDG9qPqXGLoQpT41OKvRKg.png" alt="total employee count" width="800" height="392"></p>
</div><figcaption class="imageCaption">Rosetta Stone actually shrunk by 4% in the last year…</figcaption></figure>
<figure id="b32e" class="graf graf--figure graf-after--figure">
<div class="aspectRatioPlaceholder is-locked">
<p><img decoding="async" class="graf-image alignnone" src="https://cdn-images-1.medium.com/max/800/1*g8RBZPtCNWQ25HViUY4HrQ.png" alt="total employee count 2" width="800" height="392"></p>
</div><figcaption class="imageCaption">… while Duolingo grew by&nbsp;33%.</figcaption></figure>
<p id="d4dc" class="graf graf--p graf-after--figure">As a mathematician and computer scientist, Duolingo’s co-founder Luis von Ahn did not always believe in the power of <a href="https://www.superside.com/blog/product-page">product design</a>.</p>
<p id="5ffc" class="graf graf--p graf-after--p">But now, when asked for the most life changing book he’s ever read, he’d tell you it’s “The Design of Everyday Things” by Don Norman. Since he’s read the book, he’s <strong class="markup--strong markup--p-strong">obsessed with how products are designed</strong>.</p>
<p id="0b2c" class="graf graf--p graf-after--p graf--trailing">And as a team lead by scientists, Duolingo doesn’t just improve design based on personal feelings. It uses <strong class="markup--strong markup--p-strong">data as its guiding star</strong>. 🌟</p>

<hr class="section-divider">

<h2 id="27e8" class="graf graf--h3 graf--leading">Three goals, three Duolingo teams: learning, growth and monetization</h2>
<p id="0acc" class="graf graf--p graf-after--h3">For Duolingo, the <strong class="markup--strong markup--p-strong">right</strong><strong class="markup--strong markup--p-strong"> user behavior</strong> means:</p>
<ul class="postList">
<li id="9c04" class="graf graf--li graf-after--p"><strong class="markup--strong markup--li-strong">Learning</strong>: people are more successful at learning</li>
<li id="9f50" class="graf graf--li graf-after--li"><strong class="markup--strong markup--li-strong">Growth</strong>: more people learn</li>
<li id="68ec" class="graf graf--li graf-after--li"><strong class="markup--strong markup--li-strong">Monetization</strong>: more revenue is generated to support its cause</li>
</ul>
<p id="5995" class="graf graf--p graf-after--li">That’s why Duolingo decided to create <strong class="markup--strong markup--p-strong">three teams</strong> to work on these three goals: a learning team, a growth team and a <a href="https://optad360.com/services/mobile-app-monetization/">monetization</a> team. 💡</p>
<p id="dd71" class="graf graf--p graf-after--p graf--trailing">Each team is responsible to improve the <strong class="markup--strong markup--p-strong">metrics</strong> linked to its specific goal by organizing <strong class="markup--strong markup--p-strong">product experiments</strong>.</p>

<hr class="section-divider">

<h2 id="a7b4" class="graf graf--h3 graf--leading">5 Duolingo product experiments</h2>
<p id="603c" class="graf graf--p graf-after--h3">The Duolingo homepage already gives a good idea of some of the ways its product is built to incite the right user behavior.</p>
<figure id="342c" class="graf graf--figure graf-after--p">
<div class="aspectRatioPlaceholder is-locked">
<p><img decoding="async" class="graf-image alignnone" src="https://cdn-images-1.medium.com/max/800/1*1xURC-G51XkVPnp-KmLoog.png" alt="gamification poured into every lesson" width="800" height="364"></p>
</div><figcaption class="imageCaption">Screenshot from the Duolingo homepage.</figcaption></figure>
<p id="97fc" class="graf graf--p graf-after--figure">The fact that the software doesn’t even use “hearts” anymore, and doesn’t mention <a href="https://certifier.io/blog/free-digital-badge-templates">badges</a> or its in-app coach “Duo”, is a clear example of how quick and often Duolingo runs product experiments to improve the product.</p>
<p id="202a" class="graf graf--p graf-after--p">Here’s <strong class="markup--strong markup--p-strong">5 notable experiments</strong> and the concrete impact they had. 👇</p>
<h3 id="b507" class="graf graf--h4 graf-after--p">1/ Delayed&nbsp;signup</h3>
<p id="3d36" class="graf graf--p graf-after--h4">The Duolingo team found that by allowing users to sign up later and experience some Duolingo lessons first, it could boost the amount of <strong class="markup--strong markup--p-strong">daily active users by 20%</strong>. 💥</p>
<p id="03bd" class="graf graf--p graf-after--p">Based on these experiments the team introduced “<strong class="markup--strong markup--p-strong">soft walls</strong>”. Those are optional pages that ask people to sign up, but still allow them to hit “Later”.</p>
<p id="d8fa" class="graf graf--p graf-after--p">Finally, after a series of lessons, there’s a “<strong class="markup--strong markup--p-strong">hard wall</strong>” that requires users to sign up. 🛑 The team found that the performance of this wall was actually also improved by the presence of the “soft walls” as users were already primed to sign up.</p>
<p id="456b" class="graf graf--p graf-after--p">In the process of introducing the “soft walls”, Duolingo made a mistake it later had to correct: the team created a big red “Discard my progress” button. What it found later is that this button actually invited people to click on it instead of scaring them from clicking. Replacing it afterwards with a <strong class="markup--strong markup--p-strong">more subtle grey “Later” button</strong> made performance shoot up.</p>
<figure id="9779" class="graf graf--figure graf-after--p">
<div class="aspectRatioPlaceholder is-locked">
<p><img decoding="async" class="graf-image alignnone" src="https://cdn-images-1.medium.com/max/800/0*hMqE78GPCcVTj0GI.jpg" alt="save your duolingo progress by signing up" width="640" height="514"></p>
</div>
</figure>
<p id="eead" class="graf graf--p graf-after--figure">The team was able to improve daily active users <strong class="markup--strong markup--p-strong">by another 8.2%</strong> with these subsequent experiments. An extremely significant amount. 😲</p>
<h3 id="3f93" class="graf graf--h4 graf-after--p">2/ Streak</h3>
<p id="3e34" class="graf graf--p graf-after--h4">Another important product aspect the Duolingo team experimented with a lot, is the concept of the “streak”, which it borrowed from the gaming industry.</p>
<p id="def6" class="graf graf--p graf-after--p">That means: if a user uses Duolingo for x consecutive days he or she builds up a streak. Users start feeling invested and they try not to break this streak. They <strong class="markup--strong markup--p-strong">reward persistence</strong>. 🎁</p>
<p id="0d5a" class="graf graf--p graf-after--p">I’m personally on a 152 day streak right now and it’s my best motivation to keep going. 💪</p>
<figure id="b537" class="graf graf--figure graf-after--p">
<div class="aspectRatioPlaceholder is-locked">
<p><img decoding="async" class="graf-image alignnone" src="https://cdn-images-1.medium.com/max/800/1*6a6_XYSXAiLmAgnwS-HJAw.png" alt="jeroen corthout's duolingo streak" width="625" height="141"></p>
</div><figcaption class="imageCaption">Yup, proud of it&nbsp;😏</figcaption></figure>
<p id="de37" class="graf graf--p graf-after--figure">The <strong class="markup--strong markup--p-strong">power of the streak</strong> on retention is so strong that the Duolingo team spends a lot of time optimizing it. It mainly makes it harder to lose the streak and make it easier to get it back by doing some exercises.</p>
<p id="1d55" class="graf graf--p graf-after--p">The team introduced “weekend amulets”, “streak repair”, “streak freeze”, … so that people can make up for their human failures. Introducing the amulet alone was responsible for a 4% increase in 14 day retention. ✨</p>
<figure id="3a4d" class="graf graf--figure graf-after--p">
<div class="aspectRatioPlaceholder is-locked">
<p><img decoding="async" class="graf-image alignnone" src="https://cdn-images-1.medium.com/max/800/1*3R-HMIHt3y7adCFvzTIZpQ.png" alt="power-ups in duolingo" width="800" height="354"></p>
</div>
</figure>
<h3 id="6d02" class="graf graf--h4 graf-after--figure">3/ Notifications</h3>
<p id="7d4f" class="graf graf--p graf-after--h4">On top of that, the team was able to improve conversions over notifications by around 5% just by changing the <strong class="markup--strong markup--p-strong">copy</strong> and by testing <strong class="markup--strong markup--p-strong">different timings</strong>.</p>
<p id="5fdf" class="graf graf--p graf-after--p">One of the most famous copy experiments is this <strong class="markup--strong markup--p-strong">passive aggressive notification</strong>: “Hi! It’s Duo. These reminders don’t seem to be working. We’ll stop sending them for now.”</p>
<figure id="1f75" class="graf graf--figure graf-after--p">
<div class="aspectRatioPlaceholder is-locked">
<p><img decoding="async" class="graf-image alignnone" src="https://cdn-images-1.medium.com/max/800/0*XurmOc1NYkOsT0Vp.jpg" alt="duolingo reminder notifications" width="270" height="187"></p>
</div>
</figure>
<p id="c151" class="graf graf--p graf-after--figure">In terms of timing, the team found that <strong class="markup--strong markup--p-strong">23.5 hours</strong> after their past learning session was the best moment to remind people to do their next session, as people usually learn at the same moment of the day.</p>
<h3 id="959e" class="graf graf--h4 graf-after--p">4/ Badges</h3>
<p id="5636" class="graf graf--p graf-after--h4">A classic <strong class="markup--strong markup--p-strong">gamification</strong> aspect the Duolingo team added is badges.</p>
<p id="4ff1" class="graf graf--p graf-after--p">Badges display the <strong class="markup--strong markup--p-strong">user behavior</strong> Duolingo wants to promote. This includes: spending lingots (Duolingo’s virtual currency), starting wagers, keeping streaks, learning during weekends, being active in Duolingo’s built-in language clubs, …</p>
<figure id="afeb" class="graf graf--figure graf-after--p">
<div class="aspectRatioPlaceholder is-locked">
<p><img decoding="async" class="graf-image alignnone" src="https://cdn-images-1.medium.com/max/800/1*3oV1l3PsU043LiQrfFf9OA.png" alt="duolingo achievements" width="800" height="756"></p>
</div>
</figure>
<p id="6052" class="graf graf--p graf-after--figure">The first version of the badges system by itself (even without badge tiers, i.e. the stars in the above screenshot) already increased <strong class="markup--strong markup--p-strong">daily active users by 2.4%</strong>.</p>
<p id="f04d" class="graf graf--p graf-after--p">But it also <strong class="markup--strong markup--p-strong">stimulated very specific positive behavior</strong>: it increased purchases from the Duolingo store by 13% and increased the amount of friends added by 116%.</p>
<h3 id="85eb" class="graf graf--h4 graf-after--p">5/ In-app&nbsp;coach</h3>
<p id="b07f" class="graf graf--p graf-after--h4">One of the more <strong class="markup--strong markup--p-strong">controversial</strong> experiments within the Duolingo team was the introduction of the in-app coach called “Duo”, the <strong class="markup--strong markup--p-strong">supportive owl mascot</strong>. Some team members loved it, some disliked it and found it annoying.</p>
<figure id="364f" class="graf graf--figure graf-after--p">
<div class="aspectRatioPlaceholder is-locked">
<p><img decoding="async" class="graf-image alignnone" src="https://cdn-images-1.medium.com/max/800/0*4udf9h-kWVsYXTWj.jpg" alt="duolingo shop" width="800" height="1422"></p>
</div><figcaption class="imageCaption">Duo can even change clothes. What’s not to like?&nbsp;😏</figcaption></figure>
<p id="a2e1" class="graf graf--p graf-after--figure">Personal tastes aside, the guiding data star is always right. 🌟</p>
<p id="6eed" class="graf graf--p graf-after--p graf--trailing">The introduction of Duo <strong class="markup--strong markup--p-strong">improved 14 day retention by 7.2%</strong>. Almost as big a success as the badges. 🚀</p>

<hr class="section-divider">

<h2 id="0369" class="graf graf--h3 graf--leading">Duolingo keeps lining up product experiments</h2>
<p id="f369" class="graf graf--p graf-after--h3">Duolingo understands that stopping their improvement process means standing still. And standing still means failing in the end.</p>
<p id="4df7" class="graf graf--p graf-after--p">On the other hand, there’s an <strong class="markup--strong markup--p-strong">infinite amount</strong> of product experiments one can run and mindlessly starting experiments can prove to be a total waste of time.</p>
<p id="c706" class="graf graf--p graf-after--p">That’s why the Duolingo team diligently keeps track of all possible product experiments, prioritizes them, and then plans them in accordingly.</p>
<p id="13ee" class="graf graf--p graf-after--p">To <strong class="markup--strong markup--p-strong">keep track</strong>, Duolingo adds the list of experiments to JIRA. <em class="markup--em markup--p-em">(Note: Use whatever works. At Salesflare, we use GitHub for this instead of JIRA.)</em></p>
<p id="3b0b" class="graf graf--p graf-after--p">To <strong class="markup--strong markup--p-strong">prioritize</strong>, they have 2 simple cost-benefit prioritization rules:</p>
<ol class="postList">
<li id="56dc" class="graf graf--li graf-after--p">What’s the <strong class="markup--strong markup--li-strong">potential impact</strong> of the experiment? <em class="markup--em markup--li-em">The Duolingo team even decided that experiments with an impact of below 1% are not worth it.</em></li>
<li id="0207" class="graf graf--li graf-after--li"><strong class="markup--strong markup--li-strong">How long will it take</strong> to run the experiments?</li>
</ol>
<p id="5a8b" class="graf graf--p graf-after--li">Finally, when planning, they make a consistent choice to not ignore the small experiments in favor of the big ones. <strong class="markup--strong markup--p-strong">They believe that it’s the succession of an enormous amount of tiny improvements that leads to big results.</strong></p>

<hr class="section-divider">

<p id="24e1" class="graf graf--p graf--leading">Way to go, Duolingo! 🙌 Keep going strong on your awesome mission.</p>
<p id="8c90" class="graf graf--p graf-after--p graf--trailing">The Salesflare team loves you. 😍</p>

<hr class="section-divider">

<p id="cefa" class="graf graf--p graf--leading graf--trailing"><em class="markup--em markup--p-em">Want to check out more Iconic Products? </em><a class="markup--anchor markup--p-anchor" href="https://blog.salesflare.com/iconic-products"><em class="markup--em markup--p-em">Read the entire series here!</em></a> 📲</p>

<hr class="section-divider">

<p><em>We hope you liked this post. If you did, spread the word!</em></p>
<p>👉<em> You can follow @salesflare on</em> <em><u><a href="https://twitter.com/salesflare">Twitter</a></u></em>, <em><u><a href="https://www.facebook.com/salesflare/">Facebook</a></u></em> <em>and</em> <em><u><a href="https://be.linkedin.com/company/salesflare">LinkedIn</a></u>.</em></p>
---

## Related

- [Typeform: Turning forms into human conversations](https://blog.salesflare.com/iconic-product-typeform-e17f49419c56.md)
- [How Intercom became a unicorn product](https://blog.salesflare.com/how-intercom-became-a-unicorn-product-b952bb8575c5.md)
- [The keys to Trello’s incredible growth](https://blog.salesflare.com/the-keys-to-trello-incredible-growth-e7229c3fe2b9.md)
- Previous: [Be in control of your CRM](https://blog.salesflare.com/be-in-control-of-your-crm-deadb33c43d0.md)
- Next: [David Darmanin of Hotjar](https://blog.salesflare.com/david-darmanin-hotjar-5b489a00dc28.md)
