If you design for mobile, you design for both iOS and Android. Here's everything you need to know about the key design decisions.

**Navigation patterns**

iOS lives in tabs at the bottom. Android lives in navigation drawers and bottom navigation. The key insight: both platforms have converged on bottom navigation as the primary pattern for consumer apps, but the back button behaviour is fundamentally different.

**Type scale**

iOS uses San Francisco. Android uses Roboto. Neither can be overridden meaningfully. Design your type hierarchy to work with the system font, not against it.

**Gesture navigation**

iOS has had gesture navigation since 2017. Android has had it since 2019. Both platforms have effectively eliminated the navigation bar for most use cases. Design for swipe-from-edge navigation on both.

**The home indicator (iOS) and navigation bar (Android)**

Both platforms have a persistent element at the bottom of the screen. Account for it in every full-screen experience. Ignoring it produces janky UIs that clip content.

**Material You vs Human Interface Guidelines**

The philosophical difference: Material You is more prescriptive and component-driven. HIG is more principle-driven. Material You assumes you're using Android's components. HIG assumes you're building native.

**The practical advice**

Design for one platform first and adapt. Start with iOS if your target demographic is urban, premium. Start with Android if your target is broader Indian market (75%+ of Indian smartphones are Android).