When comparing cross-platform technologies it’s interesting to see which apps you already know use what technology and what we can learn from their approaches. Here’s an overview of popular apps using Kotlin Multiplatform (KMP) and resources they’ve shared about it.
The materials I’ve found particularly interesting I’ve marked with a star ⭐ emoji, so keep an eye out for those. Be aware that resources written before the introduction of KMP Beta (October 2022) may refer to outdated issues like coroutine «» async/await interoperability, areas which have been greatly improved by now. Resources marked with a ▶️ play emoji are videos.
If you search for 2021 or 2022 on this page, you’ll find that many companies were already using KMP in production before it reached even beta. With the promotion to stable planned for this year, there’s no doubt about Kotlin Multiplatform’s readiness for production use.
📃 There are many more apps & companies using KMP, this is just a hand-picked list of the ones I personally found the most interesting. I also excluded some companies that talked about their KMP efforts at events, but haven’t published anything about it online yet.
📈 All download numbers mentioned here are from Android only and captured in July, 2023. Usage numbers from iOS, web and possibly desktop are not included.
Kotlin Multiplatform Mobile (KMM) is an older name. It used to mean the Android & iOS specific parts of KMP, but JetBrains now says there’s no need to differentiate those front-ends from desktop, web and also back-end. It’s all called KMP from hereon!
Let’s start with some enormous apps. McDonald’s (300M+) and Deezer both obtained over a hundred million downloads on Android alone. Cash App and Careem are following their trail, having achieved more than 50 million downloads each.
There is one software name on this page that’s not currently using KMP, but is still migrating towards. That name is Google Workspace, which exists of Google Docs, Slides, Sheets, Drive and Meet. The existing apps have billions of downloads and Google is in the process of migrating from their in-house J2ObjC transpiler to KMP.
- Mobile multiplatform development at McDonald’s — 2023, architectural overview
- Scale McDonald’s with KMM — ⭐▶️ video, 2023, architectural overview, interop, state management, journey from trying KMP to scaling it to the full app
- Cash App KMP case study — 2021
- Weird and Ambitious Multiplatform Things — ⭐▶️ video, 2022, Cash App’s multiplatform journey, iOS interop, developer collaboration, libraries, advice on starting with KMP
- Careem KMP case study
- Kotlin Multiplatform in Google Workspace — ▶️ video, 2023, migration from Java»Obj-C transpilation to KMP
- Kotlin Multiplatform success stories — ▶️ video, 2022, Baidu, Deezer, Shopify (who uses KMP in a React Native app)
Next up we have Memrise, Quizlet, 9GAG, Kuaishou, VMware, Meetup, Todoist and FootballCo’s GOAL apps.
- Memrise case study — 2021, sharing between Android, iOS and web (JS), Compose & SwiftUI on top of it.
- Adopting Kotlin Multiplatform Mobile (KMM) on 9GAG App — ⭐ 2022, architectural overview, comparison with Flutter, steps towards KMP.
- Kuaiying | Kotlin Multiplatform Mobile — ⭐ 2022, write-up on advantages, stability, performance and pain points.
- VMware case study — 2019, C++ interoperability.
- The Multiplatform Revolution: How Meetup® Adopted KMM — ▶️ video, 2023, benefits, iOS adoption, advice on starting/using/convincing management.
- Meetup with KMM Libraries — ⭐▶️ video, 2023, Meetup’s journey to KMP, lessons learned, recommended libraries, moving to one shared library between four apps.
- Why iOS Developers at Todoist Wanted Kotlin Multiplatform — ▶️ video, 2022.
- Testing on Kotlin Multiplatform and a Strategy to Speed Up Development Time — 2023, mocking, asserting, test set-ups and more.
- Calling Kotlin Multiplatform Coroutines from Swift with the help of KMP-NativeCoroutines — ⭐▶️ video, 2023, comparing default suspend/async interop, manual wrappers and using the KMP-NativeCoroutines library.
This category includes PowerSchool, Down Dog, Shopify (couldn’t find a resource online), GetYourGuide, Autodesk, Polarsteps (no resource available yet), TeamSnap and last but not least: my own app Notes for Android! I haven’t written much about it yet, but I’ve been sharing code between Android and web (JS) since the beginning of 2022. Expect more articles about that in the future.
- Chalk (now PowerSchool) case study — based on alpha version, pains and gains
- Autodesk case study — Android, iOS and Windows
- GetYourGuide: Building Bridges with Kotlin Multiplatform Mobile (KMM): How we added KMM to our established App — ⭐▶️ video, 2023, tips on integrating with iOS developers, lots of tips & tricks and practical advise.
- Down Dog case study — 2021, back-end (JVM) to front-end (Android, iOS, JS), native UI on top of it
- TeamSnap: Setting up a KMP shared library — 2023, extensive example of creating, testing and publishing a KMP library to be consumed on Android and iOS.
More apps from big companies
Last but not least, here’s a bunch of apps that are either targeted at a limited audience or that I couldn’t find clear usage numbers for. These are: Meetup for Organizers, Netflix Studio, Worldline, Philips HealthSuite, Baidu Wonder, Leroy Merlin and Forbes.
- Netflix Android and iOS Studio Apps: now powered by Kotlin Multiplatform — 2020, small write-up with some used libraries mentioned
- Adopting Kotlin Multiplatform Mobile (KMM) at Meetup — 2021, architectural overview, iOS cooperation, libraries used. Note: this is an older resource, see higher up the page for a 2023 video podcast from Meetup.
- Kotlin Multiplatform: The Best Choice — ⭐ 2022, from Worldline, extensive overview of other cross-platform technologies, compilation background, architecture overview, team organisation, costs breakdown (compared with native and other cross-platform technologies)
- Philips HealthSuite case study — 2021, API design for shared code through a client SDK
- Baidu case study — ⭐ 2022, technology advantages, interesting examples of where they’re using expect/actual, debugging, multithreading issues (fixed since KMP beta)
- Leroy Merlin Case Study: Building Customer-Facing Flagship App with Kotlin Multiplatform Mobile — 2021, time savings thanks to KMP, hiring advantages, adoption tips and tricks
- Forbes Mobile App Shifts To Kotlin Multiplatform — ⭐ 2023, great writeup on the business advantages of using KMP
Any big name you think should be added to this post? Feel free to let me know.
- 2023-08-01 added GetYourGuide’s Droidcon 2023 talk recording + FootballCo app and resources.
- 2023-08-02 added TeamSnap’s blogpost + new Meetup video (thanks to Fred Porciúncula for suggesting!)
- 2023-11-14 added Forbes