Kolkatar Durga Puja — Pandal Guide & Route Planner for Kolkata

Overview

A map-first Android app for finding and planning Durga Puja pandal visits across Kolkata — about 1,020 pandals, metro-aware route planning, offline maps, and community photos, built solo in about three weeks ahead of the festival.

Problem

During Durga Puja, millions of people try to see as many pandals as they can across Kolkata in a few nights. Information is scattered across social posts and word of mouth, crowds make every wrong turn expensive, and mobile data gets unreliable exactly when you need directions. Visitors needed one place to discover pandals, plan an order, and follow it on the night.

Implementation

• Built the app in Flutter with Riverpod and GoRouter, a Drift/SQLite cache, and vector PMTiles maps that keep working offline in packed crowds.
• Imported about 1,020 pandals with zones, categories, nearest metro station, and nearby toilets, hospitals, pharmacies and police from OpenStreetMap.
• Self-hosted OSRM on a Greater Kolkata extract for real road distances, powering a route planner with ordered stops, presets, and a step-by-step "next stop" view.
• Designed photo contributions with on-device metadata stripping, presigned uploads to a private Cloudflare R2 bucket, and Gemini-assisted checks that auto-approve clean photos and queue the rest for moderation.
• Backed it with a Fastify + TypeScript API on Neon Postgres/PostGIS, passwordless email OTP, and a Next.js admin panel with live activity over WebSockets, photo moderation, and push campaigns.
• Put social features — private Squads with opt-in live location, Pujo Photo Bingo, and Pujo Wrapped — behind server-side kill switches so behaviour could change during the festival without shipping a new build.

Outcome

Shipped to Google Play production before Puja 2026, about 105 commits in roughly three weeks. The release policy froze app builds during the festival while server-side flags and the admin panel kept the experience tunable live.