Mobile App Development
Native-feeling iOS, Android, and React Native apps engineered for retention. Senior mobile engineers, pixel-perfect motion, ship-ready in 12–20 weeks.
01 — Approach
How we engage.
Mobile app development that feels native, ships fast, and stays maintainable.
SimplyRem builds iOS, Android, and React Native apps for product teams who care about how an app feels in the hand — the gesture latency, the spring of a transition, the calm of a well-considered empty state. Every engagement is led by a senior mobile engineer with shipped App Store and Play Store apps to their name. No outsourced subcontractors. No half-finished hand-offs.
What we build
- Consumer iOS & Android apps — social, lifestyle, and on-demand apps designed to retain users past day-30.
- Field & logistics apps — offline-first React Native apps with WatermelonDB sync, on-device OCR, and Bluetooth peripheral integrations.
- Fintech & payments apps — KYC flows, biometrics, Apple Pay / Google Pay, PCI-aware architectures and hardened release pipelines.
- Companion apps for SaaS platforms — slim React Native or native apps that extend a web product into the user's pocket.
- Health, fitness & wellness apps — HealthKit, Google Fit, sensor integrations, and ATT/privacy compliance done properly.
- B2B field-service & enterprise apps — MDM-friendly builds, SSO, and CI/CD pipelines your IT team will sign off on.
Why teams choose our mobile app development services
- Native performance, even on React Native. 60fps animations with Reanimated, lazy-loaded screens, JSI-bridged modules where it counts.
- Senior-only delivery. A staff-level mobile engineer owns the project from kickoff to App Store submission — no juniors quietly billed at senior rates.
- Offline-first by default. Sync, conflict resolution, and graceful degradation are designed in from week one, not bolted on at the end.
- Design that respects each platform. iOS feels like iOS, Android feels like Android. Editorial-trained designers, motion designed alongside layout.
- Submission & review handled. We manage the App Store and Google Play review process — privacy nutrition labels, screenshots, App Privacy report, and rejection appeals included.
- Stay-on retainers. Most clients keep us on after launch to ship monthly releases, tune crash-free rates, and absorb new OS versions.
Native vs. React Native — what should you choose?
We are agnostic, and we will tell you honestly. Native (Swift / Kotlin) is the right call when you depend on a rapidly-evolving platform API, push the GPU hard, or need every millisecond of battery. React Native is the right call when 70–90% of the codebase is product-shaped (forms, lists, navigation), you want one team shipping two platforms, and you can absorb a thin native module layer where the rendering or performance demands it. Most of our engagements over the last three years have been React Native with a small Swift/Kotlin module pocket — but we ship pure native builds whenever the brief points there.
Our mobile app development process
1. Discovery (1–2 weeks)
We audit competitive apps, interview your users, and prototype the riskiest interactions in code — not Figma — so you know in week two whether the gesture, the animation, or the offline flow can actually be built the way it was sketched.
2. Design & architecture (2–3 weeks)
High-fidelity prototypes with motion specified frame-by-frame, plus a written architecture: data flow, sync strategy, navigation graph, deep-link map, analytics taxonomy, and a release plan covering beta, phased rollout, and rollback.
3. Engineering in fortnightly increments
You see a working build on TestFlight and Play Internal Track every two weeks. Crash-free rate, install-success rate, and key user flows are reviewed at every sprint — not just at launch.
4. Hardening & submission
Accessibility pass to WCAG 2.2 AA, App Store / Play Store review prep, privacy manifests, data safety forms, App Tracking Transparency handling, and a documented release runbook for your team.
5. Stewardship
Monthly retainers covering OS upgrades (iOS 18 → 19, Android 15 → 16), library churn, A/B tests, App Store optimisation, and the slow steady work of pushing crash-free rate from 99.4% to 99.9%.
The mobile app development stack we ship
- Cross-platform: React Native (bare or Expo), TypeScript, Reanimated, Gesture Handler, Reanimated Skia for custom rendering.
- Native iOS: Swift 5/6, SwiftUI, Combine, Core Data, CloudKit, WidgetKit, App Intents.
- Native Android: Kotlin, Jetpack Compose, Room, WorkManager, Hilt, Material 3.
- Sync & data: WatermelonDB, Realm, SQLite, GraphQL with Apollo, offline mutation queues.
- Backend & infra: Node.js / Rust APIs, Firebase, Supabase, AWS Amplify when it earns its keep.
- Release engineering: Fastlane, EAS, GitHub Actions, Sentry, Firebase Crashlytics, Detox & Maestro for E2E.
Who we work with
Our mobile app development clients are typically Series A–C startups with a senior product owner, or product teams inside established brands who need an outside studio to ship a flagship app the internal team cannot prioritise. We do our best work when the brief is ambitious — retention, performance, motion quality — and the people on the other side care about craft as much as we do.
Engagement models & pricing
- Fixed-scope build — $90k–$400k+, three to six months. Best for a flagship iOS / Android launch or a single-platform pilot.
- Cross-platform sprint — $150k–$300k, four to five months. React Native build covering iOS and Android from one codebase.
- Embedded squad — monthly retainer, two to four engineers. Best for ongoing product evolution alongside your internal mobile team.
- Discovery sprint — $25k, two weeks. A de-risking exercise that produces a prototype, architecture, and a fixed quote.
We are booking new mobile engagements one quarter at a time. Tell us what you are building — we respond to every brief within one business day.
02 — What's included
Every engagement ships with.
Senior lead
A 10+-year practitioner who stays on the work, end-to-end.
Design system
A scalable foundation, not screen-by-screen one-offs.
Production deploys
Fortnightly increments to a staging URL.
Documentation
Runbooks, ADRs, and onboarding materials.
03 — Process
Four phases. Always.
Discovery
1–2 weeks. Audit, listen, scope.
Design
2–4 weeks. Prototypes you can click.
Build
6–16 weeks. Two-week cadences.
Stewardship
Ongoing. Continuity beats handoff.
04 — Common questions
Frequently Asked Questions
How much does mobile app development cost?
A flagship iOS or Android app from SimplyRem typically lands between $90,000 and $400,000 for a fixed-scope build, depending on complexity, integrations, and whether it is single-platform or cross-platform. Two-week discovery sprints start at $25,000. We publish honest ranges because we would rather discuss budget on the first call than weeks into a proposal cycle.
How long does it take to build a mobile app?
A typical first release ships in 12–20 weeks. Cross-platform React Native builds usually fall around 16 weeks; native iOS-only or Android-only builds at the same scope are slightly faster. We work in two-week sprints with a TestFlight / Play Internal Track build at the end of every sprint, so you see real product fortnightly.
Should I build a native app, React Native app, or Flutter app?
We are agnostic and will tell you honestly. Native Swift or Kotlin is the right call when you push the GPU hard, depend on cutting-edge platform APIs, or need maximum battery efficiency. React Native is the right call when most of the app is product-shaped (forms, lists, navigation) and you want one team shipping two platforms. We use Flutter rarely — happy to discuss the trade-offs.
Do you handle App Store and Google Play submission?
Yes. Every engagement includes App Store and Play Store submission — privacy nutrition labels, App Privacy report, data safety forms, screenshots, ASO copy, and rejection appeals. We have been through every common review failure mode and most uncommon ones.
Can your mobile apps work offline?
Yes — offline-first is our default. We use WatermelonDB or Realm with conflict-resolving sync engines, optimistic mutations, and graceful degradation. We have shipped apps for logistics, field service, and remote-area healthcare that work for days without connectivity.
Do you build the backend API as well as the mobile app?
Yes, when needed. We are a full-stack studio — see our web application development services. About half of our mobile engagements include a custom backend (Node.js, Rust, or Python), and the other half integrate with an existing API the client already owns.
Will the app be accessible and privacy-compliant?
Yes. We ship to WCAG 2.2 AA by default, support Dynamic Type, VoiceOver, TalkBack, and Reduce Motion. App Tracking Transparency, privacy manifests, and platform privacy disclosures are handled as part of submission — not "phase two".
Do you offer ongoing app maintenance after launch?
Yes. Most mobile clients keep us on a monthly retainer covering OS upgrades, library churn, A/B testing, crash-rate tuning, App Store optimisation, and new feature rollouts. Mobile is never "done" — and we price the ongoing work accordingly.
05 — Selected work
Related projects.
— From the journal