Mobile app development / iOS · Android · Cross-platform / Building apps since 2017

Mobile App Development Company That Ships.

Apps people actually keep on the home screen.

We're a mobile app development company specialising in native iOS app development, Android app development, and cross-platform mobile apps. Built for user retention, App Store approval, and revenue from day one. Every app ships to the stores on the first review, runs smooth on the cheapest phone, and earns back its build cost inside the first year.

Build an app — from healthcare app development to fintech — that users love and the business grows with
Transform the idea into a high-performance mobile experience
Launch on App Store & Play Store on the first review — transparent mobile app development cost, fixed-price from day one
Active users
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Today · Monday
Almost there.
8.4K
Steps today
Active min
42
Heart rate
68 BPM
Start workout
App rating
4.8/5
Years building mobile
12+ yrs
Apps shipped
300+
App store rating
4.8/5.0
Avg D30 retention
87%
Starting at
$15K
Single platform MVP
Most projects
$25K–$60K
Custom dual-platform apps
Enterprise
$75K+
Complex integrations & compliance
Every project
Fixed price
Quote in 24 hrs · No surprises
Get a quote →
01 / How we build

iOS, Android & Cross-Platform App Development — Three paths. One team.

We don't have a religion about native vs. cross-platform — we have a decision tree. Performance-critical or hardware-heavy? Native. Standard CRUD + speed-to-market? Cross-platform. We'll tell you which on the first call.

Pillar 01

Native iOS

Swift and SwiftUI when the experience matters more than the timeline. Custom animations, hardware integration, HealthKit, ARKit — everything Apple lets you reach.

  • Swift · SwiftUI · UIKit
  • Apple SDKs & frameworks
  • First-try App Store review
Pillar 02

Native Android

Kotlin with Jetpack Compose for modern Android, or the classic XML stack when the legacy demands it. Built for the diverse Android ecosystem, not just the latest Pixel.

  • Kotlin · Jetpack Compose
  • Material 3 design
  • Multi-device, multi-API
Pillar 03

Cross-platform & hybrid

Our React Native development and Flutter app development services deliver both stores at once without two codebases. We keep 80%+ shared code, drop to native for the parts that need to be felt.

  • React Native · Flutter
  • One team, two stores
  • 30–40% faster to ship
02 / Services

Mobile App Development Services — Six services. One studio.

Full-lifecycle mobile app development servicesiOS app development, Android, and cross-platform app development. One team, no handoffs — the engineer who wrote the API also briefs the screen.

Pull-to-refresh that doesn't stutter, haptics that feel native, gestures that match system conventions. Built in Swift — not approximated.

Swift SwiftUI UIKit Core Data HealthKit · ARKit WidgetKit
What you get
  • Native iOS app
  • TestFlight beta program
  • App Store submission
  • Full source code ownership

Android is the harder platform — three OEMs, five form factors, ten years of API surface. We build with Kotlin and modern architecture (Jetpack, Compose, Hilt) so the app feels current today and is still maintainable in 2030.

Kotlin Jetpack Compose Material 3 Room · Hilt Java (legacy)
What you get
  • Native Android app
  • Play Store closed beta
  • Play Store publishing
  • Multi-device QA matrix

2026 cross-platform is not 2018 cross-platform. New Architecture in React Native, Skia and Impeller in Flutter — performance is finally on par for 90% of apps. We pick the framework based on the team, the integrations, and what your future hires will actually want to maintain.

React Native Flutter Expo Xamarin (legacy) Native modules
What you get
  • iOS + Android in one build
  • Shared business logic
  • Native modules where needed
  • OTA update pipeline

Most apps die from a thousand small slownesses, not one big bug. We profile the cold start, audit the bundle, fix the dropped frames, and bring the install size down. The result: an app that feels new on a three-year-old phone.

Cold-start profiling Bundle audit Memory leaks Image pipeline Lazy loading
What you get
  • Performance audit doc
  • Cold-start < 2s
  • 60fps scroll baseline
  • Crash-free rate > 99.5%

Mobile apps are the easiest attack surface in your stack. Tokens in plain text, keychain misuse, unverified deep links — every audit catches at least one. We build security in from sprint one: encrypted storage, certificate pinning, biometric auth, jailbreak detection, OWASP MASVS-compliant.

Encryption at rest Certificate pinning Biometric auth HIPAA · GDPR · SOC 2 OWASP MASVS
What you get
  • Threat model doc
  • Pen-test ready build
  • Compliance package
  • Privacy nutrition labels

Beautiful is the baseline; usable is the bar. Our designers ship in Figma with motion specs, prototype every flow with real data, and run usability testing before a single line is written. Platform conventions where they matter — distinctive brand where it doesn't.

Figma · Auto Layout Motion specs Apple HIG Material 3 Usability testing
What you get
  • Wireframes & flows
  • Hi-fi Figma file
  • Interactive prototype
  • Design system handoff
03 / Tech stack

Mobile App Tech Stack — The tools we actually use.

No "and many more." Our React Native development, Flutter app development, and native stack — narrow on purpose. Every framework on this list has shipped at least three production apps from our team in the last 18 months — selected through rigorous code review, benchmarking, and real-world load testing. Our product roadmap approach means your tech stack is chosen for where you're going, not just where you are today.

iOS

Apple

SwiftUI for new iOS app development builds, UIKit when the legacy demands it.

Swiftv5.10
SwiftUIiOS 16+
UIKitlegacy
Core Datastorage
Android

Google

Kotlin-first with Jetpack Compose; Java for legacy codebases.

Kotlinv2.0
Jetpack ComposeM3
Javalegacy
Room · Hiltcore
Cross-platform

Hybrid

React Native or Flutter; framework choice is a one-call decision.

React Native0.74
Flutterv3.22
ExpoSDK 51
Xamarinlegacy
Backend

Cloud

Firebase for speed, AWS for scale, Node when we own the API.

FirebaseAuth · FS
AWSLambda · S3
Node.jsv20 LTS
Supabasewhen fit
04 / App types

What we've shipped.

300+ custom mobile app development projects across a dozen verticals — each with its own platform fit, compliance regime, and definition of "done." Here's where we've done it most.

01Healthcare & telehealth
02Fitness & wellness
03Fintech & banking
04Ecommerce & D2C
05Real estate & proptech
06Edtech & learning
07Logistics & field ops
08SaaS companion apps
09On-demand & marketplaces
10Social & community

Healthcare apps

HIPAA-grade telehealth, patient portals, and clinician tools — passed App Store review on the first try.

Fitness & wellness

HealthKit-integrated trackers, on-demand class apps, sleep and recovery tools with retention as the north star.

Fintech & banking

KYC flows, biometric auth, double-entry ledgers, push notifications regulators actually approve.

Ecommerce & D2C

Headless storefronts, Apple Pay & Google Pay, push-to-cart retention loops, and live commerce features.

05 / Process

Our App Development Process — Four steps. No mystery.

Custom mobile app development from MVP to enterprise. Every mobile application development project runs in two-week agile development sprints with live device demos at each milestone — faster time to market, no black boxes with a live demo at the end of each. No surprise scope, no surprise invoices, no theatrics — just shipping.

01
Week 1–2

Discovery & strategy

We analyze your requirements, audience and business goals, then write a mobile strategy that commits to platform, framework and MVP app development scope. Most clients start with an MVP app development engagement and scale from there.

Deliverables
  • Product brief
  • Tech architecture doc
  • Roadmap + sprint plan
02
Week 3–5

Design & prototyping

Wireframes → hi-fi Figma → interactive prototype. Tested on real users before a line of Swift or Kotlin gets written.

Deliverables
  • Wireframes + flows
  • Hi-fi Figma prototype
  • Design system
03
Week 6–14

Development & testing

Two-week sprints. CI/CD, automated tests, dedicated QA. You see it running on a real device every other Friday.

Deliverables
  • Bi-weekly demo builds
  • TestFlight + closed beta
  • Automated QA matrix
04
Week 14+ · Ongoing

Launch & support

We handle App Store and Play Store submissions, write the listing copy, and stay on for maintenance. Monthly performance reports, quarterly feature releases.

Deliverables
  • Store submission package
  • Monthly maintenance
  • Quarterly feature releases
06 / Best practices

How We Build Mobile Apps — Three rules we won't break.

After 300+ apps, three principles have stayed constant. If a project goes wrong, it's almost always because one of these slipped — so we make them non-negotiable.

Rule 01

Native performance first

Cold-start under two seconds, scroll at 60fps, no jank on a three-year-old phone. Native performance, offline support, and push notifications that actually deliver — these are the numbers your users feel, and the difference between a 4.8 and a 3.2 App Store rating.

Rule 02

One codebase when possible

Scalable architecture from day one. Cross-platform isn't a compromise in 2026 — it's a 40% timeline savings and one team to maintain. We default to React Native or Flutter and drop to native only where it earns its keep.

Rule 03

Platform-native UX

Apple HIG on iOS, Material 3 on Android. The shared 80% of the design stays consistent; the platform-specific 20% follows local conventions. Users notice the difference — even when they can't name it.

07 / Case studies

A few of the things we've shipped.

Mobile, web, SaaS — across healthcare, fintech, ecommerce and real estate. Same team, end to end.

Featured Healthcare Mobile + Web
Telehealth
Healthcare · Mobile + Web · HIPAA

HIPAA-grade telehealth, from idea to App Store in 14 weeks.

A multi-state telehealth provider needed a clinician-facing iOS app, a patient-facing web app, and the SEO pipeline to fill them. One team, one roadmap — native iOS in Swift, React web app, Epic EHR integration, PHI-compliant data architecture.

14wks
Idea → live
4.9
App Store rating
3.2×
Patient signups
1st
App Store submission
Swift / SwiftUI React HIPAA Epic EHR FHIR R4 AWS HealthLake
D2C Ecommerce
D2C
D2C · Headless Commerce · Paid Social

Headless storefront + paid social, built for scale.

Replatformed a $4M/yr D2C brand to a headless React Native storefront, rebuilt the Meta and Google funnels, and stood up the email/SMS retention engine. LCP dropped from 6.2s to 2.1s on mobile — conversion followed.

2.1s
LCP mobile
+38%
Conversion rate
5.4×
ROAS (paid)
$4M
Annual revenue
React Native Next.js Shopify Storefront API Meta Ads Klaviyo
Real Estate Multi-tenant SaaS
Real
Real Estate · Multi-tenant SaaS · iOS + Android

A listings & lead-gen SaaS that onboards agents in a day.

Multi-tenant SaaS with white-label mobile storefronts, lead routing, local SEO baked in, and a paid funnel that pays back inside the first month. React Native for cross-platform parity, Node.js backend, Stripe billing from day one.

800+
Active tenants
28days
Payback period
94%
Y1 retention
1day
Onboarding time
React Native Node.js PostgreSQL Stripe AWS
Fintech Compliance-first
Fintech
Fintech · Compliance-first · iOS + Android

KYC, ledger, dashboards — compliance-first, fast second.

Built the KYC onboarding flow, double-entry ledger, and customer dashboards for a regulated fintech startup — passing the first compliance audit on the first sitting. Flutter for cross-platform, Python/FastAPI backend, 99.99% ledger accuracy in production.

1st
Compliance audit pass
99.99%
Ledger accuracy
9mo
Idea → regulated launch
1st
App Store submission
Flutter Python / FastAPI PostgreSQL Stripe KYC APIs
08 / Said about us

Mobile App Development Reviews — What people actually say.

A 4.8 average across 300+ shipped apps, and a list of clients who came back for the second, third and fourth product. Here are a few of the words they sent in.

First mobile app that passed App Store review on the first try in my career. The clinical UX work alone was worth the engagement.
DK
David Klein
CTO · Healthcare provider
They shipped a React Native app that genuinely feels native on both stores. The handoff was so clean our internal team picked it up in a week.
AR
Anjali Rao
Head of Product · Fintech
Bi-weekly demos on a real device, every other Friday, for six months. That alone is worth twice what most agencies charge. The app is great too.
MS
Maya Suresh
Founder · D2C wellness
09 / FAQ

Mobile App Development FAQ — Quick answers.

The questions founders ask on the first call. If yours isn't here, message us — there's a real person reading.

Native iOS, native Android, and cross-platform with React Native or Flutter. MVP to enterprise. If it ships on the App Store or Play Store, we've built one.

Performance budgets set in week one, tracked every sprint. Cold-start under 2s, 60fps scroll, profiled on a three-year-old phone — not a flagship.

Yes — end-to-end. Strategy, design, development, QA, store submission, and post-launch support. One team owns the outcome.

iOS: Swift, SwiftUI, UIKit. Android: Kotlin, Jetpack Compose, Java for legacy. Cross-platform: React Native, Flutter, Xamarin. Backend: Firebase, AWS, Node.js, Supabase. We pick the stack that fits the project, not the other way around.

Encryption at rest and in transit, certificate pinning, biometric auth, jailbreak detection, secure enclave usage on iOS, Keystore on Android. Compliance built in: HIPAA, GDPR, SOC 2, PCI as needed. Every project ships with a threat model and pen-test-ready build.

Four phases: Discovery & strategy → Design & prototyping → Development & testing → Launch & support. Two-week sprints with a real-device demo at the end of each. Bi-weekly invoices match bi-weekly demos.

Yes. We write the listings, prepare the screenshots, run privacy nutrition labels, submit, and respond to reviewer feedback. First-try approvals are the standard outcome — not the lucky one.

30 days included on Basic, 90 on Professional, 12 months SLA on Enterprise. Monthly maintenance retainers thereafter — OS upgrade compatibility, security patches, analytics review, quarterly feature releases.

Basic: $15K+ (simple, single platform). Professional: $35K+ (both stores, feature-rich). Enterprise: $75K+ (complex, integrations, compliance). Custom scopes for anything outside that envelope. Every quote is fixed-scope, fixed-price.

Basic apps: 2–3 months. Professional builds on both stores: 4–6 months. Enterprise platforms with advanced integrations or compliance: 6–12 months. We commit to a timeline in week one and demo against it every two weeks.

Yes — payments (Stripe, Adyen, Apple Pay, Google Pay), social logins, analytics (Mixpanel, Amplitude, Firebase), CRMs (Salesforce, HubSpot), messaging (Twilio), maps, and whatever else your stack needs. SDK integrations are bread and butter.

Free 30-minute consultation. We'll discuss the idea, surface the real requirements, recommend a platform and framework, and send a fixed-scope quote within 48 hours. No NDA needed for a first call — pitch deck not required.

Free consultation · 30 minutes

Start Your App Development Project.

Tell us about your idea — native iOS, native Android, or cross-platform app development. As a dedicated app development company, a real human responds inside 24 hours, usually faster. We'll send back a platform recommendation, rough timeline, and a fixed-scope quote.

Or skip the form — Contact@siznex.com · +1 437 254 2512
Ready to build your app? Get a quote →