Mobile · React Native, Flutter, iOS, Android

Mobile apps that ship, get reviewed, and stay running

React Native with Expo, Flutter, or fully native Swift and Kotlin when the use case demands it. Fastlane CI, push notifications, offline first storage, in app purchases, and App Store and Play Store submission included. AI accelerated build, human reviewed at every merge.

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RG INSYS builds production mobile apps for B2B and consumer clients across the UK, US, UAE, and India. We pick the right tool, not the trendy one, and we treat the unglamorous parts of mobile, store submission, push reliability, offline sync, IAP, accessibility, as first class engineering, not afterthoughts.

What we deliver: A shipped iOS and Android app on your developer accounts, Fastlane CI, push notification pipeline, offline storage with sync, in app purchases where relevant, and store listings.
Typical timeline: 8 to 16 weeks for a first release. Retained engineering thereafter for iteration and platform updates.
Pricing from: $18,000 fixed price for a focused first version, or $4,500/month retained engineering.
Stack: React Native + Expo, Flutter, Swift (iOS), Kotlin (Android), Firebase, RevenueCat, Sentry, Fastlane.
Compliance-ready for: GDPR, HIPAA, COPPA, ATT (App Tracking Transparency). WCAG 2.2 AA accessibility.

What's included

Everything you need, end to end

📱

Cross platform or native

React Native + Expo for most apps, Flutter when custom UI matters more than ecosystem maturity, native Swift and Kotlin for apps with heavy on device ML, AR, or hardware integration. We choose during architecture, not by reflex.

🛬

App Store and Play Store

Provisioning, signing, store listings, screenshots, privacy declarations, ATT and Play Data Safety forms, first review cycle. We have shipped through both stores enough times to know which rejections are coming before reviewers find them.

🚀

Fastlane CI

GitHub Actions plus Fastlane for both platforms. Beta builds to TestFlight and Google Play Internal Testing on every main merge. Phased rollouts, crash gates via Sentry, and hot fixes via Expo updates where the architecture allows.

🔔

Push that actually arrives

APNs and FCM through a single orchestration layer. Topics, segments, scheduled and triggered sends. Quiet hours, opt in tracking, delivery receipts. Bad push UX kills retention, we treat it as a product surface.

📴

Offline first storage

Realm, WatermelonDB, or SQLite with a sync layer, chosen by data shape. Conflict resolution defined per entity, not hoped for. The app works on the underground; writes reconcile cleanly when the network returns.

💰

In app purchases done right

RevenueCat for IAP and subscriptions across both stores. Entitlements verified server side, refunds and family sharing handled, grace periods configured. Stripe added for web only purchases when the product spans both surfaces.

Our method

How a mobile build actually unfolds

Scope and choose stack

One week. We decide React Native, Flutter, or native based on UI fidelity, hardware needs, hireability, and time to market. Output: a written architecture document and a fixed price quote.

Foundation and pipeline

Sprint 1. Project skeleton, design system, Fastlane CI, crash reporting, analytics, and a clickable build on TestFlight by end of week two.

Build features

Fortnightly sprints, demos on real devices. AI scaffolds screens and API integration; senior engineers handle navigation, performance, native modules, and accessibility.

Submit and harden

Store submission, first review cycle, phased rollout, and a 30 day post launch stabilisation. Crash free sessions above 99.5% is the launch quality bar.

Our tech stack for mobile

The right stack is the one your engineers can maintain a year from now without us. We deliberately bias toward boring, well documented tools and away from anything that requires a custom build of itself. Native code lives behind clean module boundaries so a future team can swap layers without a rewrite.

React Native + Expo Flutter Swift (iOS native) Kotlin (Android native) TypeScript Firebase (FCM, Auth, Crashlytics) RevenueCat (IAP) Realm / WatermelonDB / SQLite Fastlane GitHub Actions Sentry PostHog (mobile analytics)

Proof

A representative case study

EdTech · Cross Platform App UK based learning platform, React Native + Expo

A learning platform shipped to App Store and Play Store in 12 weeks, offline first lessons and in app subscriptions

A UK EdTech client needed an iOS and Android companion app to their web LMS, with offline lesson playback, in app subscriptions, and weekly push reminders. RG INSYS shipped React Native + Expo with WatermelonDB for offline content, RevenueCat for IAP, and Fastlane on GitHub Actions for CI. First store releases live in 12 weeks; crash free sessions stayed above 99.7% through the first quarter.

12 wksTo both stores

99.7%Crash free sessions

1 codebaseiOS + Android

IAPSubscriptions live

Read full case study →

Pricing

Transparent pricing

From $18,000 build

Or $4,500/month on a retained engineering model. Fixed price for first release, retainer for everything after.

Architecture sprint: $2,000 (credited to build)
8 to 16 week first release: from $18,000
Ongoing retainer: from $4,500/month
Dedicated mobile engineer: from $2,400/month

Full pricing & engagement models →

Transparent. No hidden fees. Free 48-hour estimate.

FAQ

Common questions

React Native, Flutter, or native?

For most B2B and content heavy apps, React Native + Expo is the right default: one codebase, fast iteration, and easy hiring. Flutter is excellent when you need high fidelity custom UI on both platforms. Native Swift or Kotlin is reserved for apps with heavy on device ML, ARKit/Core ML, advanced background processing, or hardware integration.

Do you submit the app to the stores for us?

Yes. We handle Apple App Store and Google Play submission end to end: provisioning profiles, signing, store listings, screenshots, privacy declarations, App Tracking Transparency configuration, and the first review cycle. You retain the developer account in your name.

How do you handle push notifications?

Firebase Cloud Messaging for Android and APNs for iOS, usually orchestrated through a single backend service (OneSignal or in house). Topic, segment, and per device sends. Quiet hours, opt in tracking, and delivery receipts are wired in from day one for compliance.

What about offline support?

Offline first is a deliberate design choice, not an afterthought. We use Realm, WatermelonDB, or SQLite with a sync layer, depending on data shape. The app stays usable on the underground, and writes reconcile cleanly when the network returns.

Can you build in app purchases and subscriptions?

Yes. RevenueCat is our default for IAP and subscriptions across both stores. We wire entitlement checks server side, never trust the client, and handle refunds, grace periods, and family sharing. Stripe is added for web only purchases when the app supports both surfaces.

How do you handle CI and releases?

Fastlane on GitHub Actions for both iOS and Android. Beta releases via TestFlight and Google Play Internal Testing on every merge to main. Phased rollouts and crash gating via Sentry or Crashlytics. Hot fixes through Expo updates where applicable to skip the store review queue.

Do you cover accessibility?

Yes. iOS VoiceOver and Android TalkBack support, dynamic type, sufficient contrast, and large touch targets are part of the definition of done. WCAG 2.2 AA is the floor for UK and EU clients.

What is the typical timeline and cost?

8 to 16 weeks for a first release depending on scope, integrations, and store readiness. Fixed price from $18,000 for a focused first version, or $4,500/month retained engineering for ongoing work.