Expert Professional Solutions
Cross-Platform Mobile App Engineering | React Native & Expo
Investment RangeCustom Project Based Scope
Building high-performance, offline-first native mobile applications from a unified codebase.
Building individual apps for iOS and Android doubles code maintenance overhead and fragments product deployment. I engineer high-performance cross-platform mobile apps utilizing modern Expo ecosystems while retaining the ability to write custom native bridges (Swift, Kotlin) for deep device-level hardware mapping. My systems feature robust offline-first caching architectures built on C++ speed layers like MMKV and local SQLite configurations, keeping interfaces completely responsive under any network constraint. From advanced push notification delivery pipelines via Firebase Cloud Messaging to secure biometric authorization (FaceID/TouchID) and rigorous App Store / Google Play runtime compliance compliance, I cover the entire publishing path.
Key Technologies & Platforms Used
React NativeExpo WorkflowTypeScriptMMKV StorageSQLiteFirebase FCMApp Store ConnectGoogle Play Console
Scope of Deliverables
- Custom cross-platform mobile application development using React Native & Expo
- Native platform modules bridging for specialized iOS & Android hardware access
- High-speed, offline-first architectures utilizing MMKV & SQLite caching
- Secure biometric authentication integration (FaceID, TouchID, Android Fingerprint)
- Interactive push notification infrastructure using Firebase Cloud Messaging (FCM)
- Advanced performance tuning, main-thread fluid animations, and memory leak resolution
- Complete app store submission management for Apple and Google platforms
Let’s Build Something Exceptional Together
Every project I take on is managed and delivered using high-performance engineering workflows and industry-standard project frameworks. I don't just write code; I establish production-grade technical scaffolding that ensures your application is scalable, maintainable, and built to last.
Engineering Workflows & Delivery Guarantees:
- •Transparent Asynchronous Execution: Active project tracking via Jira & Linear with structured, data-driven sprint cycles.
- •Rigorous MVP Prioritization: Enforcing strict MoSCoW parameters to maximize features while eliminating budget waste.
- •Industrial-Grade Automation: Event-driven backend workflows and custom API integrations built on FastAPI, Node.js, and Python.
- •Modern Elite Stack Integration: Type-safe, ultra-fast applications engineered with Next.js, React, Node.js, and Python.
- •Full IP Ownership: You retain 100% ownership of the GitHub repositories, containerized Docker environments, and cloud infrastructure setups created.
Frequently Asked Questions
Get technical answers to common questions about this service, operational workflows, and delivery mechanics.
When do you choose an Expo workflow over a Bare React Native project structure?
I utilize modern Expo Config Plugins, which eliminate the need to maintain separate, complex iOS and Android native folders manually. This approach lets me write custom native code safely while leveraging Expo's fast build pipelines, automated over-the-air (OTA) updates, and streamlined upgrade paths.
Why do you use MMKV storage for local application caching instead of traditional AsyncStorage?
AsyncStorage relies on asynchronous bridge serialization, which can cause noticeable interface lag when parsing large datasets. In contrast, MMKV is written in C++ and interfaces directly with your JavaScript context using JSI (JavaScript Interface). This delivers read and write operations that are up to 30 times faster, keeping your application responsive.
How do you guarantee smooth 60FPS scrolling performance when rendering large data lists?
I utilize optimized listing solutions like `FlashList` from Shopify, which recycle item views to minimize memory layout overhead. I ensure that layout components avoid inline function allocations, wrap complex sub-views in `React.memo`, and move heavy data filtering tasks off the main interface thread onto background execution layers.
What is your approach to handling seamless over-the-air (OTA) application updates in production?
I implement Expo Updates to push urgent bug fixes and content updates directly to users' devices without waiting for app store review cycles. However, native runtime changes-such as adding a new hardware plugin-still go through the standard App Store and Google Play submission pipelines to prevent application crashes.
How do you implement secure biometric user authentication on iOS and Android devices?
I utilize the `expo-local-authentication` module to interface directly with iOS FaceID/TouchID and Android biometrics systems. The application requests hardware authentication from the OS kernel, receiving a cryptographically verified success token without ever accessing or storing the user's private biometric data directly.
How do you prevent UI layouts from shifting across different mobile screen sizes and aspect ratios?
I build responsive layouts using relative flexbox dimensions combined with device safe-area insets. I avoid hardcoded pixel heights, use scalable font sizing units, and test UI components across a wide range of simulated device profiles to ensure consistency on both compact phones and large tablets.
What is your workflow for configuring push notification categories and interactive button actions?
I link your application with Firebase Cloud Messaging (FCM) and Apple Push Notification service (APNs) through unified notification managers. I define specific interaction channels and payload categories, allowing users to trigger background API actions directly from their lock screen notification banners.
How do you diagnose and resolve memory leaks in production React Native applications?
I identify memory issues by profiling active application execution using Flipper and the Chrome Developer Tools allocation timeline. I look for uncleaned global event listeners, unresolved promise chains, and lingering component timers, refactoring those hooks to release memory correctly when components unmount.
What steps do you take to secure sensitive API access tokens stored on mobile devices?
Sensitive credentials, access tokens, and private user keys are never saved in standard plaintext storage. Instead, I utilize the `expo-secure-store` utility, which encrypts data before saving it into the device's secure hardware layer-specifically iOS Keychain and Android KeyStore.
How do you ensure application compliance with strict Apple App Store Review guidelines?
I run apps through an internal pre-review checklist before submission. I verify that the app includes explicit privacy policy links, configures necessary data tracking permission prompts (like App Tracking Transparency), provides clear test credentials for app reviewers, and handles missing network connections gracefully without throwing unhandled exceptions.
Client Success & Feedback
Read feedback and ratings from verified client projects delivered on Upwork, Fiverr, and directly.
Fiverr Verified
“Bhalli's offline-first setup works flawlessly. Our active users log workouts entirely offline, and their progress data syncs perfectly to our databases the split-second they reconnect.”
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