Things I learned about SoundCloud

At Mobile@Scale 2016

Bohdan Orlov

Badoo

SoundCloud

• 175+M Montly active users
• 20 mobile engineers
• 2 apps (iOS, Android and React Native)

Find way to share

• BFF - mobile oriented API
• Skippy - C++ audio playback library
• Ideas and experience - priceless

Lava layers

"Successive, well intentioned , changes to architecture throughout the lifetime of the project can lead to a fragmented and hard-to-maintain codebase"

Android

• Vertical approach
• Feature by feature
• Iterative using features flags

iOS

• "Big bang" approach
• Dispose legacy code (from agency)
• Write new code applying "architecture"

Confront technical debt.

Pros

• nice architecture
• got rid of legacy
• dramatically reduced crash rate 

Cons

• No releases during conversion
• Some of existing features had to be dropped

Rewriting iOS app

Team organisation

• Tried Feature Teams
• Engineers feelt isolated
• Reverted *

* but will try again

Other things

• Core Data

• Reactive Cocoa

• Dependency inversion (?)

• Release trains with feature flags

• CocoaPods based feature separation (failed)

Don't do

well intentionedpremature

changes