Interview Questions › Product Design

Design an indoor navigation app for mega shopping malls

Design a mobile indoor navigation and shopping companion app for massive multi-level shopping centers (200+ stores across 4 floors) that guides shoppers directly to stores, restrooms, and their parked car.

Context

GPS satellite signals do not penetrate concrete mall structures, leaving shoppers lost, wandering multiple floors, and struggling to find specific brand stores or their parked vehicle.

Clarifying questions to ask first

• How does the app detect floor level transitions? (Barometric pressure sensors + BLE beacon triangulation).
• Can users search for specific items or stores only? (Stores, categories, restrooms, ATMs, and baby changing stations).

How to approach it

1. Understand Shopper Frustrations: Multi-floor confusion, broken physical directory kiosks, cannot locate restrooms/elevators with strollers, forgetting where the car is parked in massive multi-story garages
2. Technical Positioning Architecture: BLE Beacons + Wi-Fi RTT + AR Visual Inertial Odometry for sub-meter multi-floor indoor positioning
3. Design Core Feature Suite:
4. 1. AR Live View Walking Arrows (Look through phone camera to see floating 3D arrows directing you to Zara on Floor 3)
5. 2. "Accessible Stroller / Wheelchair Route" (Navigates exclusively via elevators, skipping escalators and stairs)
6. 3. "Smart Multi-Store Route Planner" (Calculates the most efficient walking path to visit 4 stores without backtracking)
7. 4. 1-Tap "Find My Parked Car" Navigation

Framework: Shopper Journey & Lost Navigation Pain Points -> Indoor Positioning Tech (BLE/AR) -> Feature Design (AR Live View, Floor Selector, Stroller Mode) -> Parked Car Locator -> Metrics

Sample answer

• 2D flat maps fail when navigating 5 floors; AR camera arrows overlaying the physical mall corridor make wayfinding effortless
• Forgetting where the car is parked is the #1 exit frustration

1. MVP: Multi-floor searchable directory, AR camera walking directions, step-free accessibility toggle, real-time parking spot pin, and promotional store discount pins along walking route

Executive design: An AR-powered indoor mall navigator providing multi-level 3D camera wayfinding, step-free accessible routes, multi-store trip optimization, and parked car return guidance.

What interviewers look for

• Indoor Multi-Floor Positioning Architecture
• AR Camera Wayfinding UX
• Accessibility & Stroller Routing Modes
• Multi-Store Trip Optimization