Mobile App Development Agency New York

2,000+

brands shipped

55+

countries served

14 wk

MVP to store

48 h

scoped quote

Mobile app developers design and engineer applications that run natively on iOS and Android devices, or cross-platform through frameworks like React Native and Flutter. We build the whole stack: UI, authentication, offline caching, push notifications, in-app purchases, deep links, background sync, analytics, and the CI/CD pipeline that ships updates to both stores.

Mobile platforms are moving targets. Apple ships a new iOS every September with API deprecations and changing App Store rules. Google does the same on Android. A mobile app developer keeps the app shipping through all of it, not just writing code once.

The work breaks into six categories: mobile-first UI and UX design, native or cross-platform engineering, backend APIs (often on our SaaS stack), release engineering, retention instrumentation, and post-launch optimization.

in short

Mobile app developers ship iOS (Swift), Android (Kotlin), or cross-platform via React Native and Flutter, end-to-end.
Native: day-zero new-API access and 60fps edge cases. React Native: 14-20 weeks vs 28-36, single team, OTA updates via EAS.
Eight-layer stack: backend, offline data, state, auth, in-app billing (StoreKit 2, Play Billing, RevenueCat), push, analytics, CI/CD.
Five retention levers ship into every build: onboarding TTV, activation event, notification cadence, habit loops, cohort reporting.
Three engagement shapes: a 14-week MVP (single platform or React Native), a production build across both platforms with retention instrumentation, or an enterprise build with SOC 2 / HIPAA. Contact for a 48-hour scoped quote.

When to hire mobile app developers.

Six signals indicate native or React Native: offline-first behavior, device hardware access (camera, BLE, NFC, HealthKit), push notifications for retention, App Store discovery, in-app purchases via StoreKit or Play Billing, and long session length. Three or more signals? Build mobile. Fewer? Consider a PWA.

01

Your product needs offline-first behavior

Fitness trackers, field-service tools, travel apps, logistics, note-taking. Web can approximate this with service workers; native does it cleanly with Core Data, Room, or SQLite and built-in background sync.
02

You need device hardware access

Camera (not file upload, real camera), microphone with low-latency capture, accelerometer, GPS with background tracking, BLE peripherals, NFC, biometric auth, HealthKit, Google Fit.
03

Push notifications are your retention engine

Web push is dying. Apple restricts it, Safari on iOS cripples it, notification permissions collapse every year. If your retention strategy runs on notifications, a native app buys you a 30-50 percentage point edge on deliverability.
04

Your users expect the App Store as a discovery channel

Consumer-first categories: fitness, meditation, finance, productivity, dating, utilities. Users search the App Store before Google. No app presence equals no shot.
05

In-app purchases or subscriptions are central

Apple IAP via StoreKit 2, Google Play Billing, RevenueCat for cross-platform reconciliation. Subscription products (fitness, creator tools, dating) live and die by native billing UX.
06

Session length is your primary engagement metric

Social, streaming, reading, gaming. 20-minute sessions on a mobile browser fight battery drain, tab switches, and notifications from other apps. Native wins every benchmark on sustained engagement.

§ 03 · the platforms

Four platforms. Senior on each.

We're senior on all four: iOS (Swift + SwiftUI), Android (Kotlin + Jetpack Compose), React Native, and Flutter. Cross-platform builds use Expo for managed workflow and EAS Build. Senior engineers, no juniors swapped mid-project.

Fig. 1 · mobile platforms · iOS + Android + React Native + Flutter

apple

iOS native

Swift 6, SwiftUI, UIKit bridging, Core Data, StoreKit 2, HealthKit, ARKit, Live Activities, WidgetKit, App Intents.

· Minimum: iOS 16
· Xcode 16, Swift Concurrency
· TestFlight → App Store

google

Android native

Kotlin, Jetpack Compose, Room, Hilt, WorkManager, CameraX, Play Billing, Material 3, Adaptive Layouts.

· Minimum: API 26 (Android 8)
· Android Studio Meerkat, KMP-ready
· Internal → Closed → Open → Production

cross-platform

React Native

RN 0.77+ with New Architecture, Expo EAS, Reanimated 3, MMKV, React Query, Zustand, React Navigation 7.

· TypeScript strict mode
· Over-the-air updates via EAS
· Native modules in Swift/Kotlin

cross-platform

Flutter

Flutter 3.x, Dart 3, Riverpod, go_router, drift, Firebase, Impeller renderer, Material and Cupertino.

· Strict null safety
· Shorebird for code push
· Native platform channels

Native vs. React Native.

React Native launches both platforms in 14-20 weeks with one team. Native (Swift + Kotlin) takes 28-36 weeks across two teams but gives day-zero API access and peak performance. We make this call in week one based on your actual constraints. Choosing wrong costs a quarter or a bad user experience.

Factor	Native (Swift + Kotlin)	React Native
Build cost (both platforms)	1.6, 2.0×	1.0× baseline
Performance ceiling	Highest (60fps at edge cases)	Excellent for 95% of apps
Time to ship both platforms	28-36 weeks	14-20 weeks
Native APIs at launch (iOS/Android)	Day-zero	1-3 months lag
Team size (for parity)	2 teams (iOS + Android)	1 team
OTA updates	Store review each time	EAS Update (JS changes)
Complex camera / AR / ML	Best	Possible via native modules
Right call when	Apple-grade UX, heavy hardware, sub-1% performance edge matters	Content apps, SaaS companions, consumer MVPs, time-to-market

We build both. The call comes out of the Discover week , not from a sales deck.

§ 05 · the full stack

The app, end to end.

Eight layers, one team: backend APIs, offline data (Core Data, Room, SQLite), state management, authentication (Apple Sign In, passkeys, biometric), billing (StoreKit 2, Play Billing, RevenueCat), push messaging (APNs, FCM, OneSignal), analytics (Amplitude, PostHog, Firebase), and release (Fastlane, GitHub Actions, EAS Build).

backend

API + server

Node.js, FastAPI, Supabase, Firebase, tRPC. GraphQL or REST depending on call patterns.

data

Local + offline

Core Data, Room, SQLite via drift, MMKV, WatermelonDB. Offline-first architecture by default.

state

State management

SwiftUI Observation, Compose State, Zustand, Riverpod, React Query. Minimal reactivity, maximum clarity.

auth

Authentication

Apple Sign In, Google Sign In, passkeys, magic links, biometric guard. Clerk, Auth0, or custom per project.

payments

In-app billing

StoreKit 2, Play Billing, RevenueCat, Stripe (non-IAP flows). Subscription receipts and webhook reconciliation.

retention

Push + messaging

APNs, FCM, OneSignal, Braze, Customer.io. Silent push, rich media, scheduled local notifications.

analytics

Instrumentation

Amplitude, Mixpanel, PostHog, Firebase Analytics. Sentry or Crashlytics for stability.

release

CI / CD

Fastlane, GitHub Actions, Bitrise, EAS Build. Automated testing, code-signing, screenshots, store deploy.

§ 06 · the unfair advantage

We don't just ship apps. We engineer retention.

Five retention levers ship into every build: onboarding under 60 seconds, an activation event that predicts Day-30, tuned notification cadence, habit loops, and weekly cohort reporting. Most agencies ship and leave. Day-7 retention drops to 12% and growth stalls. We engineer the loop from day one.

lever · 01

Onboarding time-to-value

First moment of utility < 60 seconds from install. Cut every screen between open and win.

lever · 02

Activation event

One named event that predicts Day-30 retention. Instrument it. Optimize the funnel to it.

lever · 03

Notification cadence

Right moment, right channel, right frequency. Over-push and users disable. Under-push and they forget.

lever · 04

Habit loops

Streaks, daily rituals, progressive unlocks, social proof. The difference between a tool and a habit.

lever · 05

Cohort reporting

Weekly cohort review. Retention curves by acquisition source. Winners scale, losers get cut.

benchmark

22% → 38%

Day-7 retention lift

A typical Day-7 retention audit, shipped over 90 days. We find the activation event, fix the onboarding funnel, tune the notification cadence, add a habit loop, and wire cohort reporting. You keep the work. Your team runs the loop from week 13.

Start a retention audit

§ 07 · the process

From brief to App Store in 14 weeks.

Longer than web because of App Store review, TestFlight, and phased rollout. Faster than industry average because we start building in week 3, not week 5. Discover (1 week), Design (2 weeks), Build (6 weeks), Testing (2 weeks), Launch (3 weeks).

week 1 · discover

Brief, personas, activation event

Goals, constraints, user research synthesis, platform decision (native vs RN), tech spike if required. Activation event and Day-7 target set here.
week 2, 3 · design

Flows, visual system, high-fi screens

User flows, wireframes, Figma design system, 15-25 high-fidelity screens, prototype for usability testing, App Store preview comps.
week 4, 9 · build

Engineering, APIs, payments, instrumentation

Weekly demos. Backend + mobile in lockstep. Analytics events wired as features ship, not at the end. Crash reporting and observability from day one.
week 10 · internal

Internal TestFlight + Play Internal Testing

Our team and yours on both platforms. Dogfooding. Bug triage. Performance profiling on real devices (iPhone 11 through 17 Pro, Pixel 6 through 10).
week 11 · external

External TestFlight + Closed Beta

Up to 10,000 testers on iOS, staged rollout on Android. Feedback collection, session recording, analytics review, last-mile polish.
week 12 · store

App Store + Google Play submission

App Store Connect setup, Play Console setup, screenshots, previews, privacy manifests, data-safety form, App Tracking Transparency copy. Review turnarounds typically 24-72 hours for first pass.
week 13 · launch

Phased rollout + launch-day monitoring

1% → 5% → 20% → 50% → 100% over 5 days. Crash rate, ANR rate, session duration, and activation funnel watched in real time. Rollback plan staged.
week 14+ · optimize

Retention loops + monthly reviews

Day-7 cohort analysis, activation funnel tuning, notification experiments, habit-loop A/B tests, App Store keyword optimization, ratings and reviews management.

Three engagement tiers.

Three engagement shapes with fixed scope: a 14-week MVP (one platform or React Native), a production build (both platforms with retention instrumentation), or an enterprise build (SOC 2, SSO, HIPAA, MDM). Fixed-price quote in 48 hours. Senior delivery. Clear scope before the invoice.

mvp

Mobile MVP

14 weeks

Single platform (iOS, Android, or RN cross-platform). Core flows, auth, payments, push, analytics, CI/CD. Ready for real users. Fixed-price quote in 48 h.

Start an MVP

most picked

production

Production build

iOS + Android

Both platforms. Native or RN. Deep integrations, custom backend, full design system, retention instrumentation, launch playbook. Fixed-price quote in 48 h.

Start a production build

enterprise

Enterprise engagement

SOC 2 / HIPAA

Multi-app ecosystem. SOC 2 posture, SSO, advanced security, HIPAA if needed, MDM, offline-first architecture, multi-region deployment. Fixed-price quote in 48 h.

Scope an engagement

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Mobile app developer FAQ.

Direct answers on what mobile app developers do, app build costs, timelines, the native-vs-RN call, App Store and Play submission, retention audits, and design coverage. Canonical references at developer.apple.com and developer.android.com.

What do mobile app developers do?

Mobile app developers build applications for iOS and Android natively or cross-platform via React Native and Flutter. The scope: product discovery, UI/UX, native or RN code, backend APIs, push notifications, payments, analytics, CI/CD, store submissions, and post-launch retention work.

How much does a mobile app cost to build?

Cost depends on scope: one or both platforms, native or React Native, backend depth, retention instrumentation, and compliance needs (SOC 2, HIPAA). An MVP is 14 weeks on one platform. Production covers both. Enterprise adds compliance and multi-app architecture. We send a fixed-price quote within 48 hours of your brief.

How long does it take to build a mobile app?

14 weeks from brief to App Store for an MVP: Discover (1 week), Design (2 weeks), Build (6 weeks), Internal TestFlight (1 week), External TestFlight (1 week), App Store review (1 week), Launch and optimize (1 week). Production builds take 20-28 weeks.

Should I build native or React Native?

React Native for content apps, standard UI, and React-familiar teams. Native (Swift + Kotlin) for day-zero access to new features (HealthKit, ARKit, Live Activities), deep hardware access, or first-party UX. We recommend the choice in week one based on your real constraints.

Do you handle App Store and Google Play submission?

Yes. We handle App Store Connect, Google Play Console setup, screenshots, previews, privacy manifests, data-safety forms, ATT copy, phased rollout, and review responses. Most of our MVPs pass first submission.

Can you help improve retention on an existing app?

Yes. Day-7 retention audit: funnel instrumentation, notification cadence, onboarding time-to-value, activation metric, cohort analysis. Output is a 90-day plan targeting a named lift (e.g. Day-7 from 22% to 38%) with engineering budget.

Do you provide mobile app design as well as development?

Yes. Mobile UI/UX is core to every build. See our UI/UX design service: user research, information architecture, flows, visual system, high-fidelity screens, prototypes, and handoff-ready design system.

§ 10 · mobile development in 2026

What changed for mobile builds.

Three shifts changed the mobile landscape in 2026. React Native 0.74+ is now production-grade for commerce and content. Apple raised iOS 17 as the minimum for new apps. Android 15 and Material 3 Expressive reset the design language expectations.

The cross-platform versus native choice is now a real trade-off. React Native's new architecture closed the performance gap with native. Native still buys you deep platform features, instant new API access, and predictable review timelines. Choose based on whether you need platform depth or broad reach.

Android's Material 3 Expressive codifies new tokens and motion rules. Apps not using the new language look outdated on day one. For Shopify stores or headless commerce, React Native plus Shopify's mobile SDK is the fastest path to both platforms.

What this means for your project: in 2026, default to React Native for commerce, content, and most B2C apps; pick native (Swift, Kotlin) only when the differentiator is platform-specific (ARKit, CameraX, Live Activities, on-device ML). Budget for a six-month post-launch retention sprint; the App Store install is not the win.

Related reading + work: See our native versus hybrid mobile framework, the Shopify mobile app builders comparison, and our iOS development, Android development, and React Native development pages for adjacent work.

related · services

SaaS Development Web Development UI/UX Design Brand Identity Growth Strategy Paid Acquisition Flutter Development

ready for the store

Brief us. Ship to the App Store in 14 weeks.

One business day. A senior mobile developer reviews the brief, writes the plan, sends it back. If we're not the right fit, we say so , and often point you to a better option.

Start an app project See our work