How We Reduced Our iOS App Launch Time by 60%

DoorDash cut their iOS app launch time by 60%. Here's how they did it with three targeted optimizations that any mobile team can learn from.

Filip Busic from DoorDash's iOS performance team breaks down their systematic approach to eliminating startup bottlenecks. Using performance profiling tools, they identified three critical areas where architectural decisions were silently killing launch speed.

Key Takeaways

• Replaced String(describing:) with ObjectIdentifier for 22% faster startup
• Eliminated AnyHashable conversions for 29% improvement in launch time
• Deferred third party framework initializers to save 200ms at startup

The third optimization involved a clever trick to bypass dyld's module initializers without losing compiler safety.