Industry Leaders on the KotlinConf’25 Stage: What Global Brands Built With Kotlin

Daria Voronina

The Kotlin ecosystem continues to grow among the world’s most recognized brands, including Meta, AWS, Duolingo, Uber, and others. At KotlinConf 2025, these companies took the stage to share practical, real-world engineering stories.

KotlinConf is where developers can learn directly from the teams building products at global scale. Software engineers showcase how they are tackling challenges in navigation, performance, cross-platform architecture, build tooling, and large-scale migrations. These sessions offer rare, firsthand insights into how industry leaders use Kotlin to solve complex problems in production.

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Here’s a look at some of the standout talks from KotlinConf’25 and the global brands behind them.

Real-world Kotlin use at scale

From navigation systems and build tools to AI-driven migrations and cross-platform architectures, global brands are using Kotlin to solve engineering challenges at massive scale.

1. AWS

Blueprints for Scale: What AWS Learned Building a Massive Multiplatform Project | Matas Lauzadis, Ian Botsford

The AWS team shared firsthand insights from designing, developing, and scaling the AWS SDK for Kotlin – a massive multiplatform project spanning over 300 services and targeting eight distinct platforms. They discussed the challenges they faced, the best practices they adopted, and the strategies that succeeded (and failed) at AWS scale.

Level up your KMP expertise with our workshop on seamless code sharing ➡️ Learn more

2. Duolingo

Duolingo + KMP: A Case Study in Developer Productivity | John Rodriguez, Johnny Ye

Duolingo ships weekly to more than 40 million daily active users across 176 countries, and Kotlin Multiplatform is playing a growing role in how they move fast. In this talk, the team discussed how they delivered features like Video Call, Math, and Adventures across Android, iOS, and web, which upcoming projects may benefit from KMP, and the challenges faced and lessons learned along the way.

3. Google

Deploying Kotlin Multiplatform at Google Workspace | Jason Parachoniak, Troels Lund

The Google Workspace team discussed the bugs, performance issues, and areas for potential optimization while rolling out Kotlin Multiplatform for certain users. The session included real comparisons with Objective-C, insights into the fixes they implemented, and a Q&A session with the developers who worked on the project.

4. Meta

Build your Kotlin and Android apps with Buck2 | Sergei Rybalkin

Meta announced that Buck2, its large-scale open-source build system, now supports Kotlin and Android. The talk explored building an app from scratch and advanced Buck2 capabilities like remote execution, source-only ABI, and build tool API integrations.

5. Umain, McDonald’s App

Leveraging KMP for navigation in the McDonald’s app | Cas van Luijtelaar, Anthony Bassey

The team behind the McDonald’s app revealed how they extended Kotlin Multiplatform beyond the domain layer to handle navigation on both Android and iOS. The talk covered how they approached cross-platform navigation, the challenges they overcame, and what the architecture looks like today.

Explore how to build reusable, cross-platform UIs with Compose Multiplatform in our hands-on workshop ➡️ Learn more

6. Uber

Large Scale Changes with AI – Migrating millions of lines of Java to Kotlin at Uber | Ty Smith

Uber has one of the world’s largest Android codebases, and while Kotlin is now first-class, millions of lines of Java still need to be migrated. In this talk, the team outlined the tooling, AI-driven workflows, and processes they’ve developed to safely migrate production code at scale. They covered motivations, challenges in large monorepos, data generation for AI models, agentic systems for deterministic migrations, risk mitigation strategies, PR management, and where this technology is heading next.

Explore agentic AI development in our Kotlin workshop using JetBrains’ Koog framework ➡️ Learn more

7. X (formerly Twitter)

One Codebase, Three Platforms: X’s Experience with Kotlin Multiplatform | Arkadii Ivanov, Eric Denman

At X, a small team used Kotlin Multiplatform to rebuild a core feature for a multi-million-user platform. Their talk covered the highs and lows of adopting KMP in a real-world project. The speakers provided a rundown of their development process, architectural decisions, libraries used, cross-platform UX considerations, and the challenges of gaining buy-in across iOS and web teams. Watch the recording for a practical look at the lessons learned and how KMP transformed their cross-platform strategy.

Connect with global brands at the flagship Kotlin event of the year

KotlinConf is where the global Kotlin community comes together to share real engineering breakthroughs, practical lessons, and the ideas shaping the future of the language. At KotlinConf’26, you’ll meet the teams behind products used around the world, learn directly from the people pushing Kotlin forward, and take home knowledge you can apply immediately.

If you want to sharpen your skills, explore emerging tooling, and connect with the companies driving innovation in Kotlin, this is the place to be.

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