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

Sebastian and Pamela discuss what it means to be an expert in Kotlin Multiplatform, with the help of a panel of experts! Learn about why it's interesting to dive deep into a certain technology, recommendations on how to learn advanced topics, and general advice on how to get the most out of using KMP.

SKIE

KMP libraries:

• whyoleg/cryptography-kotlin

Interesting code to explore:

• JetBrains/kotlin
• Kotlin/kotlinx-datetime
• Kotlin/kotlinx-io
• Kotlin/kotlinx.coroutines
• Cartesian product by Jake

• Get an invite!

Ecosystem wishlist:

• wasmJs support in SQLDelight
• Compose Multiplatform support in MapLibre

Learning resources:

• Kotlin Multiplatform build setup from scratch with Sebastian Sellmair
• KEEP - Kotlin Evolution and Enhancement Process
  • HexFormat proposal and discussion
  • Uuid proposal and discussion

More KMP experts:

• Kevin Galligan
  • Bluesky
  • Twitter
• Russell Wolf
  • GitHub
  • Twitter
  • multiplatform-settings
• Jesse Wilson
  • GitHub
• Sebastian Sellmair
  • Twitter
• Salomon Brys
  • Twitter

Hosts:

• Sebastian Aigner
  • Website
• Pamela Hill
  • Blog
  • Bluesky

Guests:

• Jake Wharton
  • Website
• John O'Reilly
  • Website
  • KMP samples on GitHub
• Konstantin Tskhovrebov
  • Mastodon
• Tadeas Kriz
  • Mastodon
  • Bluesky

(0:00) Introductions

(1:40) Why be a KMP expert?

(9:14) First steps to being an expert

(16:38) Respecting each platform

(24:04) Libraries for KMP

(27:45) Advanced learning resources

(38:18) Ecosystem wishlist

(43:03) Exercising your KMP skills

(48:15) Shoutouts to other experts

(51:34) Wrap-up

Sebastian introduces the new co-host of the podcast, in a special episode recorded on location at droidcon New York! Joined by Russell Wolf, author of the multiplatform-settings library, we discuss the conference, different code sharing approaches for Kotlin Multiplatform, and how to build great multiplatform libraries.

Hosts:

Guest:

Timestamps