Restaurant mobile app: real-time menu, booking, loyalty

A restaurant loses up to 12% of orders because of an outdated menu: a guest selects a dish that is already on the stop-list. Each lost order costs an average of $25, so reducing cancellations by 20% saves $5 per order. Order cancellation means frustration and lost revenue. The cause is an architecture where the stop-list does not sync with the client in real time. We design so that when the kitchen changes something, the app instantly hides the unavailable dish. For this we use WebSocket for the stop-list, menu cache with a short TTL, and forced refresh when the cart opens. Our restaurant mobile app development ensures accuracy. Assess your project — get a consultation.

How to implement real-time menu without delays?

Two approaches. Static menu — JSON loaded at startup, cached for 24 hours. Simple, works offline. But the stop-list lags, possible orders of unavailable items. Dynamic menu — request before every action, always up-to-date, but slower and requires internet. Compromise (our choice): cache for 5–15 minutes and refresh the cart with availability check for each item. Stop-list — a separate endpoint /menu/stop-list, updated via WebSocket. Compared to traditional polling, WebSocket reduces stop-list update latency by 10 times, ensuring accuracy under 500 ms. Unavailable dishes shown with a "Temporarily unavailable" label — this reduces cancellations by 20% according to our data. Our digital menu for restaurant includes this feature.

Table booking: from floor plan to reminder

Floor plan — SVG or Canvas with clickable tables. Each table stores capacity and status (free/occupied/reserved). Status updates via WebSocket or polling every 30–60 seconds. Booking form: date, time, number of guests, name, phone. After confirmation — SMS and push notification with details. One hour before the visit — reminder push. Cancellation via the app, slot automatically freed. The table booking app reduces no-shows by 15%.

Pre-order and delivery: two scenarios

Takeaway mode — user orders in advance, specifies ready time. Statuses: received → preparing → ready. Push on each status. Delivery — separate logic: zones (polygon on map), minimum amount, cost calculation. Integration with Places API for address autocomplete. The pre-order food app allows customers to schedule orders. Our restaurant delivery app includes zone-based pricing.

Why should a loyalty program be built from the first release?

Accumulated points are the foundation of retention. Scheme: X points for Y rubles, spend no more than N% of order. Balance on the home screen. QR code for offline visits: a unique QR (JWT-signed with timestamp to prevent reuse) generated in the app, the cashier scans — points are credited. Push campaigns: "Your points expire in 30 days", "You haven't visited us in 2 weeks — here's a promo code". Segmentation via FCM Topic subscriptions. Lack of loyalty reduces LTV by 25–30% — proven on projects. A loyalty program increases average check by 20%. Order development — we include loyalty in the MVP. Our restaurant loyalty program is customizable.

POS integration

POS systems: iiko, r_keeper, Poster. Each has a REST API for order transmission. For example, iiko API: we send an order with modifiers, get orderId, track status — the chef sees the order on the kitchen screen. If integration is not in the first version — sync via a tablet app for staff with notifications. POS integration restaurant systems like iiko and r_keeper cost from $5,000. iiko mobile app integration ensures seamless order sync.

Apple's App Store Review Guidelines (4.2) mandate that push notifications must be for user interaction only, which we comply with. Push notifications restaurant campaigns improve retention.

Stack and architecture: Flutter vs native

Flutter with BLoC for order state (predictable states, easy to test). dio + retrofit for API, hive for menu cache, flutter_local_notifications + FCM for notifications. Native development — if deep integration with NFC or Bluetooth printer is needed. Flutter development is 2 times faster than native for similar features. Our cafe mobile app solution is customizable for coffee shops. Contact us — we'll select the stack for your project.

Development process

1. Menu and order flow design (wireframes)
2. Catalog and cart development (MVP)
3. Booking, loyalty, payment integration
4. POS integration (if in scope)
5. Testing all scenarios
6. Publication in App Store and Google Play

MVP costs start at $15,000. Total project cost typically ranges from $25,000 to $50,000.

What's included in development

• Requirements analysis and prototyping (wireframes)
• MVP development: menu, cart, online payment, push notifications
• POS integration (iiko, r_keeper, Poster)
• Loyalty program (points, QR, push campaigns)
• Design system for iOS and Android
• Testing and publication in App Store / Google Play
• API documentation and staff training
• 1 month post-release support

Our team's experience — 30+ projects in the restaurant industry. We guarantee quality and adherence to deadlines. As a leader in app development restaurant services, we deliver results. Get a consultation — we'll evaluate your project and propose an architecture that eliminates sync issues.

Payments in Mobile Apps: In-App Purchase, StoreKit 2, Google Billing, Stripe, RevenueCat

In every monetization project, we balance App Store and Google Play policies, PCI DSS requirements, and purchase verification logic on the backend. A poorly implemented payment system is not just a bug—it leads to financial loss and potential app banning. Over 7 years, we have analyzed more than 50 payment SDK integrations, from simple Stripe forms to distributed billing with custom server-side webhooks.

In-App Purchase: Two Platforms, Two Different APIs

If your app sells digital content or subscriptions, Apple and Google require you to use their payment systems. This is non-negotiable: violating App Store rule 3.1.1 or Google Play Developer Policy results in app removal. Physical goods and offline services are a different story.

StoreKit 2 (iOS 15+)

StoreKit 2 is a complete overhaul of the original StoreKit with async/await API. Product.products(for:), product.purchase(), Transaction.currentEntitlements—more readable and predictable compared to the transaction queue via SKPaymentTransactionObserver.

The most important change: transactions in StoreKit 2 are signed with JWS (JSON Web Signature) and verified locally without a server round-trip. Transaction.verificationResult returns .verified(Transaction) or .unverified(Transaction, VerificationError). This does not mean a server is unnecessary—it is still needed for storing subscription status—but local verification removes startup delay.

StoreKit.AppTransaction verifies the actual app download from the App Store. Required for paid downloads or non-renewing purchases.

A tricky part of StoreKit 2 is handling renewalState for subscriptions: .subscribed, .expired, .inBillingRetryPeriod, .inGracePeriod, .revoked. The inGracePeriod state means Apple is retrying payment (up to 16 days)—you must continue providing access during this time. Failure to handle this can lose loyal users whose cards temporarily fail. Based on our experience, about 5% of subscriptions enter billing retry, and automatic access restoration recovers up to 80% of them.

Google Play Billing Library (v6+)

Google Billing is more complex than StoreKit in terms of scenario handling. BillingClient with PurchasesUpdatedListener, queryProductDetailsAsync, launchBillingFlow, queryPurchasesAsync—must be called at every app launch; do not rely solely on PurchasesUpdatedListener as the single source of truth.

Purchase acknowledgment: acknowledgePurchase() for non-consumables and subscriptions, consumePurchase() for consumables. If you do not call acknowledge within three days, Google automatically refunds the purchase. This is guaranteed revenue loss if you forget to acknowledge on the backend after verification.

ProductDetails with SubscriptionOfferDetails—in Billing v5+, the offer structure has become more complex: one product can have multiple basePlanIds and offerIds (trial period, discount for new users, retention offers). BillingFlowParams.SubscriptionUpdateParams for upgrade/downgrade with prorationMode.

Why Is Server-Side Verification Mandatory?

Never trust only client-side code when unlocking paid content. Client-side verification can be bypassed by modifying the app.

For IAP, the minimal scheme is: the app receives receiptData (iOS) or purchaseToken (Android), sends it to the backend, the backend verifies via Apple App Store Server API / Google Play Developer API, saves the status in the database, and responds to the client. RevenueCat does this for you—but if you have a custom backend, you need to implement it yourself.

Webhooks are more important than they seem. Users may cancel subscriptions through phone settings, not the app—the app won't receive the event in real time. Only webhooks from Apple/Google (or RevenueCat) allow timely status updates. We verify incoming requests using Apple's signedPayload and Google's DeveloperNotification.

How Does RevenueCat Simplify Integration?

Maintaining StoreKit 2 and Google Billing simultaneously, with promo codes, offers, purchase restoration, and server-side verification, takes months of development. RevenueCat handles most of this layer.

RevenueCat is not just a payment SDK. It offers:

• A unified API for iOS and Android (and Stripe for web)
• Server-side verification and subscription status storage
• Webhooks for events (purchase, renewal, cancellation, billing issue)
• Analytics for cohorts, MRR, churn
• A/B testing of offers via Experiments

Purchases.configure(withAPIKey:) at startup, Purchases.shared.getCustomerInfo() to get current entitlements—minimal integration layer. Purchases.shared.purchase(package:) instead of directly calling StoreKit/Billing.

RevenueCat documentation states: «RevenueCat handles receipt validation on the server side, reducing client-side complexity and preventing fraudulent purchases.»

Limitations of RevenueCat: it is paid (free up to $2.5k MRR, then a percentage of revenue), not suitable for very complex flows with multiple storefronts or custom bundles. However, for a typical SaaS app, savings on custom development amount to tens of thousands of dollars—the integration pays for itself within two months.

Stripe in Mobile Apps

Stripe is used for physical goods, services, and B2B payments where IAP is not required by platform policy.

Stripe iOS SDK and Android SDK—PaymentSheet for ready-made payment UI, PaymentSheetFlowController for custom UI with saved cards. Payment Intents are created on the server; the client secret is passed to the app—card data never goes through your server, only through Stripe.

Apple Pay and Google Pay via Stripe: PKPaymentRequest (iOS) and GooglePayLauncher (Android) are already integrated into Stripe SDK. Apple Pay conversion rates are 1.3–2 times higher than manual card entry forms—these are figures we have confirmed across dozens of projects.

Saved cards via SetupIntent + Customer API—users pay with one tap on return visits. Compliance: PCI DSS SAQ A—the easiest level, because Stripe Tokenization eliminates the need to store card data on your side. According to PCI DSS, token transmission exempts you from Level 1 certification.

3DS2 (Strong Customer Authentication) is mandatory for payments in the EU under PSD2. Stripe handles it automatically via PaymentIntent.confirmPayment, but you need to correctly handle the .requiresAction status and return the user to the appropriate screen after authentication.

What Is Included in the Work (Deliverables)

Process and Timeline

We start by clarifying the business model: subscriptions, one-time purchases, consumables, freemium. The architecture depends on this. Testing IAP requires Sandbox accounts (Apple) and License Testers (Google)—this is a separate environment setup.

Apple's Sandbox behaves differently from production: subscriptions renew every 5 minutes instead of monthly, inGracePeriod works differently. It is essential to test scenarios: trial expiration, cancellation, billing retry, refund.

The cost is calculated individually based on the set of tools and complexity of server-side logic. On average, we fit within a budget for a typical integration, but the savings from preventing errors and churn offset this investment within a few months.

Get a consultation for your project—contact us. We will help you choose the optimal payment architecture that passes store reviews and does not break under peak loads.