# reCAPTCHA and Duolingo: Luis von Ahn (2020)

- Show: [How I Built This](https://hardwarepodcasts.com/podcast/how-i-built-this)
- Published: 2023-12-18
- Length: 1h 07m
- Page: https://hardwarepodcasts.com/podcast/how-i-built-this/2023-12-18-recaptcha-and-duolingo-luis-von-ahn-2020

## Summary

Luis von Ahn, co-founder of Duolingo, explains how he invented CAPTCHA to solve Yahoo's spam problem and later created reCAPTCHA to digitize books by leveraging human typing. He then pivoted to Duolingo, partnering with co-founder Severance Hacker to build a free language learning platform that initially attempted to monetize through user-generated translations for clients like CNN and BuzzFeed. When that model proved unsustainable, von Ahn adopted a freemium model with ads and subscriptions, eventually taking the company public with a valuation reaching $9 billion.

## Chapters

- [0:00](https://hardwarepodcasts.com/podcast/how-i-built-this/2023-12-18-recaptcha-and-duolingo-luis-von-ahn-2020#t=0) Introduction: Luis von Ahn and the origins of CAPTCHA
- [3:43](https://hardwarepodcasts.com/podcast/how-i-built-this/2023-12-18-recaptcha-and-duolingo-luis-von-ahn-2020#t=223) Childhood in Guatemala and early interest in machines and math
- [9:02](https://hardwarepodcasts.com/podcast/how-i-built-this/2023-12-18-recaptcha-and-duolingo-luis-von-ahn-2020#t=542) Inventing CAPTCHA to stop Yahoo spam bots
- [15:30](https://hardwarepodcasts.com/podcast/how-i-built-this/2023-12-18-recaptcha-and-duolingo-luis-von-ahn-2020#t=930) The ESP Game and Google's acquisition of image labeling tech
- [21:42](https://hardwarepodcasts.com/podcast/how-i-built-this/2023-12-18-recaptcha-and-duolingo-luis-von-ahn-2020#t=1302) Creating reCAPTCHA to digitize the New York Times archive
- [30:24](https://hardwarepodcasts.com/podcast/how-i-built-this/2023-12-18-recaptcha-and-duolingo-luis-von-ahn-2020#t=1824) Working at Google and meeting co-founder Severance Hacker
- [40:15](https://hardwarepodcasts.com/podcast/how-i-built-this/2023-12-18-recaptcha-and-duolingo-luis-von-ahn-2020#t=2415) Founding Duolingo and the initial translation-based business model
- [52:52](https://hardwarepodcasts.com/podcast/how-i-built-this/2023-12-18-recaptcha-and-duolingo-luis-von-ahn-2020#t=3172) Pivoting to a freemium model with ads and subscriptions
- [1:01:54](https://hardwarepodcasts.com/podcast/how-i-built-this/2023-12-18-recaptcha-and-duolingo-luis-von-ahn-2020#t=3714) Product philosophy, gamification, and going public

## Topics

- [Starting a product company](https://hardwarepodcasts.com/topic/starting-a-company)
- [Validation & product-market fit](https://hardwarepodcasts.com/topic/validation-and-product-market-fit)
- [Pricing, margins & unit economics](https://hardwarepodcasts.com/topic/pricing-and-unit-economics)
- [Connected products & IoT](https://hardwarepodcasts.com/topic/connected-products-and-iot)
- [Crowdfunding & preorders](https://hardwarepodcasts.com/topic/crowdfunding)

## Most relevant to

early-stage companies, companies scaling up

## Mentioned

- Yahoo (company)
- CAPTCHA (product)
- reCAPTCHA (product)
- Google (company)
- Duolingo (product)
- CNN (company)
- New York Times (company)
- Facebook (company)
- Union Square Ventures (company)
- Rosetta Stone (product)

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- [159: Build a Community to Sell Your New Product Invention](https://hardwarepodcasts.com/podcast/product-startup/2023-01-18-159-build-a-community-to-sell-your-new-product-invention) (Product Startup)
- [Arduino's Invisible Touch with Massimo Banzi](https://hardwarepodcasts.com/podcast/the-amp-hour/2026-06-17-arduinos-invisible-touch-with-massimo-banzi) (The Amp Hour)
- [S1E50 Turning Personal Challenges into New Technology | Robert Chappell](https://hardwarepodcasts.com/podcast/being-an-engineer/2020-11-13-s1e50-turning-personal-challenges-into-new-technology-robert-chappell) (Being an Engineer)
- [Founder Feature: Daniela Suarez of iCalm](https://hardwarepodcasts.com/podcast/the-startup-cpg-podcast/2024-11-01-founder-feature-daniela-suarez-of-icalm) (The Startup CPG Podcast)

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