Multi-Store Grocery App — Flutter Source Code

How the multi-store architecture works

This is the section that justifies the price step from $1,500 single-store to $3,000 multi-store. Everything below is built in. No custom engineering required to turn it on.

Per-store data model. Every store is a first-class entity with its own inventory table, price list, operating hours, slot capacity, delivery zone polygon, staff roster, commission rate, and payout schedule. Two stores in the same chain can run different prices for the same SKU, different operating hours, and different commission rates without forking the codebase. The customer app reads the right values based on the store the customer is ordering from — no overrides, no hardcoded chain-level defaults.

Multi-zone delivery engine. Delivery zones are stored as MongoDB 2dsphere polygon-defined zones. Each zone is attached to one or more stores. When a customer enters a delivery address, the backend uses $geoIntersects to find which zones cover that point, then surfaces only the stores that deliver into that zone. Each zone has its own fee structure (flat, distance-based, or surge-tiered), its own slot capacity, and its own availability hours. A dark-store operator running 12 warehouses across a metro can map non-overlapping zones per warehouse; a franchise chain can let two nearby stores both serve an overlapping zone with the closer store winning the order.

Store-level pricing and inventory. Each store manages its own stock through the store app. Out-of-stock items hide automatically in the customer app for that store only, while neighbouring stores in the same chain stay live. Promotional pricing is store-scoped or platform-scoped: a chain can run a regional coupon across all 30 stores or a single-store flash sale, and the customer app applies the right discount based on which store the cart is sourced from.

Zone-routed shopper-picker dispatch. Shopper-pickers are assigned to one or more zones. When an order comes in, the backend matches it to a shopper inside that zone. No shopper sees orders outside their assigned zones, and the routing layer never dispatches a shopper from one zone to a store in another. This matters operationally: shopper retention drops fast when the app sends them across the city for a low-margin order.

Per-store commission terms. Every store has its own commission rate (5–15%) and payout cadence. The admin panel calculates payouts per store per period, exports per-store statements, and supports franchise reporting where each franchisee sees only their own performance. Cross-store reporting at the admin level surfaces total platform revenue, order volume, and gross margin across the entire network.

Cross-store reporting at admin level. The multi-store admin dashboard rolls up data across every store: total orders, gross merchandise value, average order value, shopper utilisation by zone, refund rate per store, and CPG ad performance. Operators can scope reports by store, by zone, by category, or by date range. Per-store views drill into a single location’s P&L without leaving the dashboard.

None of this exists in the $1,500 single-store sibling. That product assumes one inventory table, one price list, one zone, and one commission relationship; adding a second store requires custom engineering. This build is the right tier the moment you have a second store on the roadmap.

Why $3,000 versus $1,500 single-store

The price step is honest scope, not branding. The $1,500 single-store grocery app ships three apps (customer, driver, web storefront) and one admin against a single-store data model. This $3,000 build ships three Flutter apps (customer, store-operator, shopper-picker) and a multi-store admin against a per-store data model with MongoDB 2dsphere zones, store-scoped inventory and pricing, zone-routed shopper dispatch, per-store commission engine, and cross-store reporting. Roughly 40% more backend surface and a different data model, not a feature flag flipped on top of the single-store product.

Pick the $1,500 sibling if you operate one location today and one location next year. Pick this $3,000 build the moment you have a second location on the roadmap. The cost of retrofitting multi-store onto a single-store codebase later (backfilling per-store inventory tables, splitting the zone model, rewriting the admin) runs 4–6 weeks of engineering at $25/hr. Buying the right tier on day one is cheaper than re-platforming on day 180.

IFA’s grocery ladder is the only Flutter-native three-tier stack we know of in this category: $1,500 single-store, $3,000 multi-store, custom from $40,000 to $80,000+. Most competitors sell either a single SaaS subscription (Deonde at $49/month forever, no source code) or a single readymade tier without an upgrade path. Three tiers means you buy the right size today and have a documented migration path when you grow.

Customisation services — $25/hr

Source code is yours after purchase. Our team handles post-purchase customisation at $25/hr or a fixed-bid quote against a defined scope. Typical multi-store customisation requests:

• Per-store POS integration. Square, Shopify POS, Lightspeed, or bespoke REST connectors. 2–4 weeks per connector depending on whether the source system pushes updates or needs polling.
• Custom zone configuration. Bespoke zone-pricing logic (time-of-day surge per zone, weather-aware delivery fees, capacity throttles per shopper supply).
• Franchise reporting templates. Per-franchisee P&L exports, royalty calculation engines, custom commission tiers.
• Subscription membership tier. BigBasket BB Now or Instacart Plus-style monthly membership — recurring revenue add-on, typically 3–4 weeks of work.
• Additional payment gateways. PayPal, Adyen, MercadoPago, or region-specific rails.
• Advanced analytics. Cohort retention by store, shopper lifetime value, zone-level unit economics.

Fixed-bid quotes start at $2,000. Hourly engagements bill weekly. Contact our team with your scope and we will come back with a quote inside one business day.