Duolingo

Duolingo is the world's most popular language-learning app, offering gamified lessons in over 40 languages. Their mobile engineering team has been a pioneer in adopting Kotlin Multiplatform and SwiftUI, serving over 100 million monthly active learners worldwide.

11 articles · iOS, Android, Kotlin Multiplatform

Website Tech Blog

Duolingo App Store

Duolingo Play Store

iOS Jun 24, 2026

How We Automated iOS Unit Test Generation with AI

iOS Jul 10, 2025

How we used Macros to Promote MVVM architecture adoption

Kotlin Multiplatform Jul 3, 2025

Duolingo + KMP: A Case Study in Developer Productivity

Android Jun 11, 2025

Duolingo's Android Performance Case Study and DAU Growth

Android May 4, 2025

How We Slashed Android Startup Time by 30% with Baseline Profiles

iOS / Android Feb 7, 2025

How we reduced manual regression tests by 70% using AI tools

iOS / Android Dec 18, 2024

How we sped up Android and iOS builds by 68% on CI

iOS / Android Nov 8, 2024

How server-driven UI keeps our shop fresh

iOS / Android Mar 1, 2024

How dogfooding helps us build a better Duolingo

Android Aug 26, 2021

Android App Excellence: Duolingo

iOS Jan 7, 2015

Real World Swift