💡 Geofence-Triggered At-the-Market Experience

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Summary

When a customer physically arrives at a farmers market, the app automatically detects proximity via geofencing and switches to a dedicated "Market Day" view showing real-time vendor check-in statuses, live vendor map positions, and walking directions to followed vendors. This transforms the in-market experience from passive browsing to active, confidence-backed navigation.

Market Signal

80% of new hyperlocal apps in 2026 use geofencing as a baseline feature. No farmers-market-specific competitor connects geofence arrival to a live vendor coordination layer — Seen Markets offers a static "digital guide" but not real-time check-in data at arrival. The hyperlocal delivery segment grows at 18–22% CAGR driven by proximity-triggered UX patterns.

User Signal

The existing Pre-Trip Confidence Dashboard idea (#371) addresses pre-trip planning but stops at the market entrance. Customers need the confidence signal to continue during the visit — especially at large markets with 30+ vendors. The PRD already requires expo-location for radius search (FR21, FR22), making geofencing a natural extension of existing architecture.

Technical Opportunity

expo-location + Expo TaskManager support hardware-accelerated geofencing out of the box with minimal battery impact. The architecture already has Firebase Realtime paths (/markets/{marketId}/vendors/{vendorId}/status) for live vendor data. The geofence simply triggers a UI mode switch to surface data that's already flowing. React Context can manage the "at-market" state toggle.

Assessment

Dimension	Score	Rationale
Feasibility	high	expo-location geofencing API is mature; Firebase Realtime paths already exist; no new backend infrastructure needed
Impact	high	Transforms the in-market experience; drives repeat usage; differentiates from every competitor in the space
Urgency	med	Valuable for Growth phase when market count increases; pilot markets can validate with manual mode switch first

Adversarial Review

Strongest objection: Users may deny location permissions, and geofencing requires background location access which iOS gates behind a secondary permission prompt.

Rebuttal: The feature gracefully degrades — without location, users can manually select a market to enter "Market Day" view. The value proposition for the permission prompt is clear and immediate ("See live vendor statuses when you arrive"). Battery impact is negligible because hardware geofencing monitors boundary crossings, not continuous GPS.

Suggested Next Step

Create a UX spike story for the at-market mode transition: define the geofence radius (recommended: 200m), the UI state switch, and the data requirements for the market-day view. Validate with expo-location geofencing API on both iOS and Android.