Building KMP Libraries: The RevenueCat Story

Sebastian and Márton discuss building KMP libraries with Jay Shortway, the author of RevenueCat’s Kotlin Multiplatform SDK for in-app purchases.

Resources:

• RevenueCat KMP SDK
• How we built the RevenueCat SDK for Kotlin Multiplatform
• Hybrid SDK Architecture at RevenueCat
• ttypic/swift-klib-plugin on GitHub
• RevenueCat/purchases-kmp on GitHub
• Consider moving `Instant` and `Clock` to the standard library · Kotlin/kotlinx-datetime
• RevenueCat openings

Hosts:

• Sebastian Aigner – Website | Bluesky
• Márton Braun – Website | Bluesky

Guest:

• Joop Korteweg – Twitter

Timeline:
(0:00) Intro
(0:44) What’s RevenueCat
(4:00) In-app purchases are hard
(7:22) The multiplatform SDK
(12:44) The demand for KMP
(16:30) Hiring and team structure
(18:42) SDKs for any framework
(21:27) Building on native SDKs
(23:45) Improving iOS linking
(24:54) The SDK is on GitHub
(26:05) Benefits of building on native
(28:18) Designing a common API
(33:21) Add-on modules for SDKs
(37:30) Instant in the standard library
(38:04) Returning results from the API
(39:53) API design decisions
(44:57) Codegen opportunities
(45:48) The best things about KMP
(47:07) KMP improvements wishlist
(48:28) The KMP journey
(49:45) Wrap-up