📱 Mobile Applications
Mobile App Developer
Build a high-performance mobile app on iOS and Android. PWA and React Native specialist: native interface, push notifications, API backend, offline sync. Car Maintenance, Fishing Log and Vinyl Tracker are among my achievements.
💡 Mobile Applications — En bref
- ⏱ Timeline : From a few days to a few weeks depending on project complexity
- 🔧 Stack : React Native, PWA, iOS, Android, Service Workers
- ✅ References : Car Maintenance, FrenchRDV, Steam Slop Cleaner
- 🌍 Area : Paris, Lyon, Marseille and all of France (100% remote possible)
- 📬 Quote : Free, response within 24h
Mobile App Expert
Developing a mobile app in 2026 means choosing between several paradigms: PWA (Progressive Web App) for maximum reach without an app store, React Native for cross-platform iOS/Android from a single codebase, or Flutter for native performance. Xavier Kain masters these three approaches and supports startups, SMEs and large enterprises in choosing the right technology for their budget, timeline and audience.
My mobile apps include offline-first PWAs (accessible without internet, installable on the home screen), React Native apps with push notifications (Firebase Cloud Messaging), geolocation and in-app payments (Stripe), and React admin dashboards to manage data. I also support teams in publishing on the Apple App Store and Google Play Store.
Mobile App Services
PWA iOS & Android
iOS & Android Progressive Web Apps: installable from Safari or Chrome without app stores, offline-first operation via Service Workers, native push notifications, camera and GPS access, and cloud sync when connection is restored. Development cost up to 3x lower than a classic native app.
React Native
Cross-platform React Native applications: a single codebase for iOS and Android, near-native performance (60 fps), smooth navigation and natural animations. Published on App Store and Google Play with Over-The-Air (OTA) updates via Expo to fix bugs without re-submitting to stores.
API Backend
Robust API backend for mobile apps: REST or GraphQL architecture, JWT authentication with refresh tokens, MySQL or PostgreSQL database, real-time synchronisation via WebSockets, and push notifications via Firebase Cloud Messaging (FCM). Scalable from 100 to 100,000 users.
Micro-SaaS app
Micro-SaaS from A to Z: conversion-oriented landing page, Stripe integration with recurring subscriptions and customer portal, secure user space with custom analytics dashboard, and retention mechanisms (push notifications, gamification). Car Maintenance, Fishing Log and Vinyl Tracker are concrete achievements.
Projects in this sector
Micro-SaaS applications designed and developed from scratch.
What clients say
“I had the opportunity to work with Xavier Kain as a UI designer and everything went perfectly. I particularly appreciated his speed of execution and responsiveness.”
“Excellent experience with Xavier for our company website redesign: responsiveness, professionalism and a touch of creativity!”
“We used Xavier's services for our website redesign and were delighted!”
Frequently asked questions
PWA or native app, which to choose?
A PWA is less expensive to develop and doesn't require app stores. It suits most use cases (tracking, management, content). A native app (React Native) is preferable for games, augmented reality or when App Store/Google Play distribution is strategic.
How long to develop a mobile app?
A simple PWA (CRUD + authentication + payment) is delivered in 6 to 10 weeks. A more complex cross-platform React Native app takes 3 to 6 months depending on features. I adopt an MVP approach to deliver a functional version quickly and iterate.
Can a PWA be published on the Apple App Store?
A PWA can be installed directly from Safari on iOS without going through the App Store (via "Add to Home Screen"). For App Store/Google Play distribution with all native features, React Native or an encapsulation solution is needed.
What is the difference between a PWA and a native iOS/Android app?
A PWA (Progressive Web App) installs from the browser without going through the stores, updates instantly and works on all platforms. A native app (Swift/Kotlin or React Native) offers full access to hardware APIs (camera, GPS, sensors), better performance and a smoother user experience for intensive use.
Can my application work offline?
Yes, offline mode is possible with two approaches: a PWA using Service Workers to cache resources and data, or a React Native app with a local SQLite database (via Expo SQLite or WatermelonDB). The synchronisation strategy with the server is then essential.
Do I need to publish on the App Store and Google Play Store?
Only for native applications. Publishing on the stores involves fees ($99/year for Apple, $25 once for Google) and a validation process. A PWA does not require going through the stores: it is accessible from the browser and can be installed directly on the home screen.
Your mobile app project?
Response guaranteed within 24h. Free and no-obligation quote.
Start your project →