After years of running React Native with JSC, switching to Hermes was a game-changer.

The startup time improvement alone — going from ~2.5s to ~0.8s cold start on mid-range Android devices — justified the migration. But the real wins were in memory consumption.

Hermes uses bytecode precompilation, which means your JS bundle gets compiled at build time rather than runtime. This eliminates the JIT compilation overhead and results in:

• 30-50% reduction in memory usage
• Consistent performance across device tiers
• Smaller APK sizes (bytecode is more compact)

The tradeoff? Some advanced JS features need polyfills, and debugging requires Hermes-specific tools. But with Flipper integration, the DX is solid.

For MedGulf's 100K+ user base spanning budget to flagship devices, Hermes was the clear choice. The crash rate on Android dropped by 40% after migration.

If you're still on JSC — make the switch. Your users (and your crash analytics) will thank you.