Lisa works on the Dev Craft team at Instagram that embarked on a journey to bring Kotlin to the Instagram for Android code base a little over three years ago. Now, nearly half of the large codebase is migrated and over 80% of newly committed code is in Kotlin. Tune in to hear what the unique challenges of bringing a new language to an existing app are and what it means for build speed, IDE experiences and developer happiness. Got feedback? Send it to us on Twitter (https://twitter.com/metatechpod), Instagram (https://instagram.com/metatechpod) and don’t forget to follow our host @passy (https://twitter.com/passy and https://mastodon.social/@passy). Fancy working with us? Check out https://www.metacareers.com/. Links Meta Engineering Blog: How Meta brought AV1 to Reels - https://engineering.fb.com/2023/02/21/video-engineering/av1-codec-facebook-instagram-reels/  Source-only ABIs for Java - https://engineering.fb.com/2017/11/09/android/rethinking-android-app-compilation-with-buck/ Timestamps Intro 0:06 Intro Lisa 1:27 Dev Craft at Instagram 3:03 Building DevX Partnerships 3:56 The History of Kotlin at Instagram 6:22 Declarative UI 18:29 Build Speed Challenges 20:25 Source-Only ABIs 23:19 IDE Performance 26:19 Kotlin at IG in 2023 27:15 Outro 32:02 Bloopers 33:07