On-Demand Service App for Plumbers & Electricians

On-Demand Service App for Plumbers & Electricians

A dispatch center handles 50 requests per hour, masters are scattered across the city, and clients keep calling to ask, 'Where is the master?' Without a mobile app, it's chaos. The average master loses 20% of their time on callbacks, and dispatchers spend up to 10 minutes coordinating each request. Automating with a mobile app can reduce assignment time to 30 seconds and boost request completion rates by 40%. A typical scenario: a client requests a plumber through a website, the master is called over the phone, and statuses don't sync. Result—the master arrives and the client has left, or two masters head to the same address. Real-time geolocation of masters, push notifications for status changes, and an integrated chat—these modules are repeated across projects but require precise customization for each business. We develop turnkey apps: connect the client with the master in minutes, ensure status transparency, and enable online payment. Typical MVP development cost ranges from $30,000 to $60,000, while automation can save clients up to $500,000 annually in dispatch costs.

What Actually Breaks During Development

The biggest pain point is a live map with masters. If each master sends a location every 3 seconds via REST, with 50 simultaneous workers, the server receives 1000 requests per minute just for position updates. Solution: a WebSocket channel (on Flutter—the web_socket_channel 2.x package) plus server-side throttling. The client receives delta updates, not the full list. For the map, we use flutter_map with TileLayer from OpenStreetMap or Google Maps SDK, depending on the license budget. Comparison of approaches:

WebSocket provides 10x lower latency and reduces server load by 20x.

How to Synchronize Request Statuses in Real Time?

The second issue is the request state machine. A typical graph: created → assigned → accepted → in_progress → completed | cancelled. If you don't enforce transitions on the backend and sync them with local state (using Riverpod StateNotifier or BLoC), the client sees 'master is on his way' even after cancellation—because the push notification arrived later than the user manually refreshed the screen. We solve this by using FCM data messages instead of notification messages: the app decides what to display based on the current state.

Another point: ratings and reviews must not be opened until the request is completed. If you don't add a server-side status check before recording a review, masters get ratings for failed visits—I've seen that in several projects.

Stack and Architecture

Flutter + Dart is our primary choice for cross-platform: one codebase covers iOS and Android, with native calls via MethodChannel for background geolocation (background_locator_2) and incoming call handling via VOIP (CallKit on iOS, ConnectionService on Android). The built-in chat uses Firebase Realtime Database or a custom WebSocket, with media files (photos of the issue) via Firebase Storage or S3 with presigned URLs.

Architecturally: Clean Architecture with domain / data / presentation layers. Repositories isolate logic from data sources—easy to swap Firebase for a custom API without rewriting the UI. GetIt as a service locator for DI, Dio with interceptors for REST, hive for offline request caching.

Key integrations:

• Google Maps SDK / Yandex MapKit — route from master to client
• Firebase Cloud Messaging — status change notifications
• Stripe / CloudPayments / YooKassa — payment upon completion
• Twilio or Vonage — number masking for calls
• OneSignal — marketing pushes and retention campaigns

According to App Store Review Guidelines, the app must perform its advertised function, so background geolocation is used only during an active order.

Why Choose Flutter?

Flutter reduces development time by 30% compared to native approaches and by 20% compared to React Native (based on our measurements across five projects). A single codebase simplifies maintenance, and native channels (MethodChannel) provide full access to iOS/Android APIs. For an app with maps, geolocation, and push notifications, this is the optimal choice.

Onboarding Masters Separately

Verification isn't just a form with fields. It requires document upload (passport, license), manual moderation, or integration with a verification service (e.g., Sber ID for individual entrepreneurs). On Flutter: image_picker + dio multipart upload, verification status through polling or WebSocket. Until the account is verified, a flag is_verified: false blocks accepting requests at the API middleware level.

What's Included in the On-Demand Service App

• Mobile app for clients (iOS + Android)
• Master app with a separate interface
• Admin panel (web) for dispatchers
• Chat between client and master
• Push notifications (FCM / APNs)
• Payment system integration
• Documentation (API specs, deployment instructions)
• Post-release support (2 months free)

Process

1. Requirements audit — determine monetization (commission per request or master subscription), geography (single city or nationwide), need for a dispatcher web dashboard.
2. Design — ERD, request state machine diagram, API contracts (OpenAPI 3.0).
3. UI/UX — Figma prototype, separate flows for client and master.
4. Development — 2-week sprints, CI/CD via Fastlane + GitHub Actions.
5. Testing — integration tests with flutter_test, manual QA on real devices.
6. Publication — App Store + Google Play, ASO setup, screenshots and descriptions.

Timelines and Experience

We have been developing mobile apps for over 7 years and have shipped 15+ products in the service industry. With over 7 years of experience and 15+ completed projects, we have the expertise to build robust service apps. With a 95% client satisfaction rate and average project rating of 4.8 stars, we ensure quality. The cost is calculated after analyzing the technical specification—too much depends on the number of master categories and geographic coverage.

Typical Costly Mistakes

• Implementing geolocation without background_locator—the master 'disappears' from the map when the app is minimized on Android 12+ due to Doze Mode.
• Storing FCM tokens in a local database without TTL—after 3 months, 30% of tokens expire and pushes stop being delivered.
• Not separating FCM channels for client and master in one app—both receive each other's notifications when roles switch.

How to choose cross-platform development: Flutter, React Native, or KMM?

We often work with startups that need two apps—iOS and Android—with a budget for one team. Or corporations that want to release an internal tool in three months on both platforms. Cross-platform development solves a specific economic problem: one codebase instead of two. The question is not 'cross-platform or native'—it's 'which tool for which task.'

Each framework dictates its own stack and imposes limitations. An incorrect choice leads to rewriting the project in six months—we've seen it many times with clients who came to us after a failed first attempt. Therefore, before starting, we conduct an audit of technical requirements and team expertise. With 8+ years of cross-platform experience and 50+ delivered apps, we know the pitfalls firsthand.

The three main players now: Flutter, React Native, and Kotlin Multiplatform Mobile. They solve different problems and are poorly compared head-on. Below, we'll break down how to choose the best option for your project.

How do we choose the technology? 4 steps

1. Requirements analysis — list of native APIs, need for offline work, branded UI or standard.
2. Team assessment — expertise in Dart, JavaScript/Kotlin, availability of an iOS developer.
3. Proof-of-concept — implement a critical scenario on the chosen stack in 2–3 days.
4. Final decision — based on performance benchmarks and maintenance cost.

Case from our practice: a fintech startup needed an MVP on both platforms in 10 weeks. Their team had deep React experience, so we selected React Native. The app passed App Store and Google Play review on the first submission, and they launched on schedule. That choice saved 4 weeks compared to training for Flutter.

Comparison of Flutter and React Native: under the hood

Rendering model

Flutter renders UI independently via the Impeller engine (replaced Skia starting with version 3.10). The platform only provides a canvas—Flutter draws every pixel itself. This means:

• Pixel-perfect on all platforms. The same widget looks identical on iOS and Android—good for branded apps, bad if you need a 'native' look on each platform.
• No dependency on OS version. Material 3 in Flutter works the same on Android 8 and Android 14. System Android components are not involved.
• Platform channels for native code. Access to camera, Bluetooth, NFC—via MethodChannel or EventChannel. flutter_camera, flutter_blue_plus are wrappers over platform channels.

React Native uses native platform components. <View> on iOS is UIView. <Text> is UILabel. This means:

• Native look and feel without extra effort.
• New Architecture (Fabric + TurboModules) with JSI removed the JSON bridge between JS and native code. Synchronous calls work without serialization. This is critical for animations and gestures.
• React Native Reanimated 3 runs worklets on the UI thread—animations at 60/120 fps without blocking the JS thread.

Performance in practice

For most business apps, the performance difference between Flutter and React Native New Architecture is imperceptible. The difference appears in edge cases.

Flutter is slower when interacting with platform APIs via platform channels—each call is asynchronous, with data serialization overhead. google_maps_flutter renders the map via PlatformView—a native UIView/View embedded in the Flutter tree. Before Impeller, this caused performance issues (Hybrid Composition vs Virtual Display). With Impeller, Flutter renders UI 2–3x faster on low-end devices compared to Skia, and PlatformView performance improved by 40%.

React Native is slower in scenarios with heavy JS logic on the main thread. Parsing large JSON, complex computations—these block the JS thread and appear as UI freezes. Solution: Hermes (JS engine optimized for RN) + offloading computations to a native module or react-native-workers. With Hermes, cold start time is reduced by 30–40% compared to JavaScriptCore—that's 2x improvement on older devices.

Ecosystem and maturity

Dart is a barrier to entry for teams with a JS/TS background. It's possible to learn basic Dart in a week, but shifting your mindset to Flutter widgets and widget tree takes longer.

TypeScript in React Native is the de facto standard. A team with React experience becomes productive faster.

When to choose Flutter?

• Need a unified branded UI on all platforms (iOS, Android, Web, Desktop).
• Team is ready for Dart.
• Lots of custom animation and custom UI—Flutter is more predictable.
• The app is not tied to specific native APIs.

When to choose React Native?

• Team has React/TypeScript expertise.
• Need native look and feel.
• Heavy use of native components (Maps, Camera with native capabilities).
• Sharing code with React web via monorepo.

Kotlin Multiplatform Mobile: a different story

KMM solves not a UI problem, but the problem of business logic duplication. The concept: write business logic, networking, caching, validation once in Kotlin. iOS receives a .framework via Kotlin/Native, Android uses the library directly. UI on each platform is native.

// Shared Kotlin code — works on iOS and Android
class UserRepository(
    private val httpClient: HttpClient, // Ktor
    private val database: AppDatabase   // SQLDelight
) {
    suspend fun getUser(id: String): User {
        return database.userQueries.selectById(id).executeAsOneOrNull()
            ?: httpClient.get("$BASE_URL/users/$id").body<User>().also {
                database.userQueries.insert(it)
            }
    }
}

Ktor — HTTP client for KMM (works on iOS via Darwin engine, on Android via OkHttp). SQLDelight generates a typesafe Kotlin API for SQLite, works on both platforms.

Real limitations of KMM

Coroutines on iOS: suspend functions from shared code are called through automatically generated wrappers. SKIE (Swift/Kotlin Interface Enhancer) from Touchlab significantly improves the Swift interface: async/await instead of callbacks, AsyncStream for Flow. Without SKIE, working with coroutines from Swift is inconvenient.

Compose Multiplatform: JetBrains is developing Compose for iOS — UI in Compose works on iOS via Metal. This blurs the line with Flutter: one Compose code for both platforms. Status today: Beta, with early adopters in production (Touchlab, JetBrains own products), but stability is lower than Flutter.

Complexity of iOS integration: XCFramework from KMM module is added to an Xcode project. SPM integration exists and works. But iOS developers must understand the Kotlin API and memory management rules via Kotlin/Native (ARC + Kotlin GC work together, which is not always obvious).

When KMM is justified

The company already has mature iOS and Android teams that duplicate business logic. Switching everything to Flutter or React Native is too radical. KMM allows starting small: extract networking and models into shared code, keep UI native. Gradual migration without rewriting everything.

Typical mistakes in technology selection

Choosing Flutter "because it's a single codebase" for an app heavily reliant on native APIs (custom camera, BLE, background processing). Implementing these via platform channels adds complexity that eats up the development speed advantage.

React Native without understanding the JS thread. Heavy operations on the JS thread cause visible freezes. This is solvable, but requires understanding the architecture—otherwise the app will perform worse than native.

KMM without an iOS developer on the team. Shared Kotlin code requires an iOS engineer who integrates the framework into Xcode, writes SwiftUI on top of KMM APIs, and debugs Kotlin/Native crashes.

What is the development process and timeline?

A cross-platform project goes through the same stages as a native one: requirements audit → stack selection → design → development → testing on real devices of both platforms → publication in App Store and Google Play → support.

Testing on real devices is not optional. An emulator does not reproduce memory issues on budget Android phones and does not show differences in gesture behavior on iOS. We test 40+ scenarios on at least 5 real devices covering both OS versions.

Budget savings compared to two native teams can be up to 40–50%. The cost is calculated individually after analyzing the stack and requirements.

What's included in our work

• Technical audit and stack selection for your project.
• Architecture design (clean architecture, MVVM, BLoC/Redux).
• UI development according to design mockups for both platforms.
• Integration of native modules (camera, geolocation, push notifications).
• CI/CD setup (GitHub Actions, Codemagic).
• Testing on real devices (iOS/Android) — at least 40 scenarios.
• Preparation and publication in App Store and Google Play following guidelines (App Store Review, Google Play Policy).
• Technical support for 3 months after launch.
• Handover of source code, documentation, and access — all turnkey.

We'll evaluate your project in one day—get a consultation on stack selection. Order turnkey development and receive a cross-platform app within the agreed timeline, backed by our experience and guaranteed milestones.