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Mobile app development, from idea to app store and beyond

CarrySo is a mobile app development company. We design, build, launch and maintain Android and iOS apps with Flutter, including SaaS mobile apps and MVPs, and we publish our own apps on Google Play, so we deal with the whole lifecycle ourselves, not only the build.

Primary technology
Flutter and Dart (one code base for Android and iOS)
Platforms
Android on Google Play (published); iOS and the App Store from the same code
Backend
Firebase (Firestore, Functions, Auth, Messaging, Crashlytics) and REST APIs
Engagements
New apps, SaaS mobile apps, MVPs, existing Flutter apps, maintenance
Discuss your app See our work

Services within mobile app development

Mobile app development is the umbrella. These pages cover each platform, product type and discipline in depth.

Platforms and technology

How the app is built and where it runs.

Flutter app development

Flutter app development for Android and cross-platform apps: architecture, state management, Firebase, on-device processing, testing and store release.

Android app development

Android app development with Flutter: apps built for real devices, published and maintained on Google Play, with Data safety, privacy policies and updates.

iOS app development

iOS app development with Flutter: iPhone and iPad apps from one code base, Apple Developer setup, TestFlight, App Store review, privacy labels and updates.

Cross-platform app development

Cross-platform mobile app development with Flutter: one code base for Android and iOS, native performance, shared tests, and lower build and maintenance cost.

Product types

What kind of app you are launching.

MVP app development

Launch a focused mobile MVP with Flutter: tight scope, real users on the app store, crash reporting and remote config, so you learn fast and iterate.

SaaS mobile app development

Mobile apps for SaaS businesses and mobile-first SaaS products in Flutter: subscriptions, auth, onboarding, dashboards, payments, push, APIs and admin panels.

AI app development

AI app development for mobile: on-device models for photo, video and text tasks, plus LLM-powered features through APIs, built into Flutter apps with Firebase.

Disciplines across the lifecycle

The work around the code: design, backend, release and upkeep.

Mobile app maintenance and updates

Mobile app maintenance for Flutter apps: crash monitoring, SDK and target API updates, Google Play policy compliance, update prompts and regular releases.

Mobile app UI/UX design

Mobile app UI/UX design that ships: user flows, wireframes, screens and a Flutter design system for Android and iOS, with onboarding, dark mode and accessibility.

Mobile app backend and API development

Backend and API development for mobile apps: Firebase (Auth, Firestore, Cloud Functions, FCM), REST API integration, security rules, admin panels and remote config.

App store deployment

App deployment to Google Play and the App Store: listings, screenshots, privacy policy, Data safety and privacy labels, signing, review, staged rollout and updates.

App rescue and existing app development

App rescue for Flutter apps: audit, stabilise and take over an existing mobile app, fix crashes and store issues, then add features on a sustainable footing.

What is mobile app development?

Mobile app development is the work of planning, designing, building, testing and publishing software for smartphones and tablets, and then keeping it working as operating systems, devices and store policies change.

A production app is more than screens. It needs local data storage, often a backend, push notifications, crash reporting, analytics, store listings, privacy disclosures and a way to push updates. We plan for all of these from the first scope document.

What we build

  • Android apps built with Flutter and published on Google Play
  • iOS apps from the same Flutter code base, released through the App Store
  • Cross-platform apps that share one code base between Android and iOS
  • SaaS mobile apps: subscriptions, accounts, dashboards, push notifications and admin panels
  • AI-powered apps: on-device models for media tasks and LLM features through a secure backend
  • MVPs that test a product idea with the smallest useful feature set
  • Offline-first apps that keep working without a connection
  • Media and utility apps that process images, video and documents on the device
  • Firebase-backed apps with remote configuration, push notifications and crash reporting

Who we build mobile apps for

We work with people who need a mobile app to exist, work reliably and keep improving, rather than a prototype or a slide deck.

  • Founders validating a product idea with a focused MVP on the app stores
  • SaaS businesses that need a mobile app for their existing web product, or a mobile-first SaaS product
  • Companies and teams that need a custom Android or iOS app for customers or staff
  • Owners of existing Flutter apps that need maintenance, new features or a rescue (see app rescue)
  • Publishers of consumer utility and media apps, the category our own products live in

Flutter, native or React Native: which should you choose?

For most new business apps that need Android and iOS, Flutter gives the best balance of speed, cost and quality, and it is what we specialise in. Native development still makes sense when an app depends heavily on platform features that arrive in Kotlin or Swift first.

How the three common approaches compare
FlutterNative (Kotlin + Swift)React Native
Code basesOne Dart code baseTwo: one per platformOne JavaScript/TypeScript code base
UI renderingDraws its own widgets, so the UI is consistent across platformsPlatform UI toolkitsPlatform components driven from JavaScript
Release buildsCompiled ahead of time to native machine codeCompiled nativelyJavaScript engine plus native modules
Best fitMost business apps, MVPs, custom UI, media toolsDeep platform integrations, OS-specific featuresTeams already invested in React

What our mobile apps can include

Capabilities from Flutter apps we have built
CapabilityHow we build it
UI and UXFlutter widgets, Material design, responsive layouts, dark themes, localisation (for example English, Spanish and Urdu in MetaClean)
State managementGetX, Riverpod or Bloc, chosen to fit the app's complexity
Offline dataIsar, Hive, Drift or SQLite for local storage; shared preferences for settings
On-device processingImage processing, FFmpeg video encoding, and on-device ML background segmentation, run in background isolates
Backend and APIsFirebase (Cloud Firestore, Cloud Functions, Storage) and REST API integration
Push notificationsFirebase Cloud Messaging with device registration and scheduled local notifications
Security and privacyBiometric lock (local_auth), secure storage, on-device processing so user files are never uploaded
QualityUnit and widget tests, Firebase Crashlytics crash reporting
MonetisationGoogle Mobile Ads with remotely controlled frequency limits
Release managementStore listings, Data safety forms, hosted privacy policies, soft and forced update prompts

The mobile app development lifecycle we follow

Every project, including our own products, moves through the same stages. Each stage links to the service page that describes it in depth.

  1. Idea

    You bring the problem, the audience and the business case. We ask what success looks like at launch and a year later.

  2. Discovery

    A written scope: who the app is for, the core workflow, integrations, platforms and the release target. This is where most cost decisions are made.

  3. UI/UX design

    User flows, wireframes and screens that follow Material on Android and feel native on iOS, designed as a Flutter theme rather than throwaway mock-ups.

  4. MVP

    The smallest version real users can install and rely on, built on the same architecture the full product will use.

  5. Development

    Flutter build in short iterations with test builds on real Android and iOS devices, so you see a working app early.

  6. API and backend

    Firebase or a REST API for accounts, sync, subscriptions, push notifications and an admin panel, added only where the product needs it.

  7. Testing

    Unit tests on parsers, repositories and controllers, widget tests, and release candidates checked on physical devices.

  8. App store

    Store listings, screenshots, privacy policy, Data safety and privacy labels, signing, review and staged rollout on Google Play and the App Store.

  9. Launch

    Crash reporting, analytics and remote configuration are live from day one, so the first week's problems are visible and fixable.

  10. Maintenance

    Crash fixes, SDK and target API updates, store policy deadlines and regular releases, run the same way we run our own apps.

  11. Scaling

    New features, more platforms, subscriptions and performance work as usage grows, without rebuilding the app.

Publishing and maintenance are part of the job

Because we publish our own apps, we build for what happens after launch. Every app we ship uses our in-house Flutter growth package. It reads configuration from Firestore, shows soft or forced update prompts, registers devices for push notifications and limits ad frequency, all without a new store release.

Our admin tooling checks each app's Google Play listing every night and flags apps whose last release is getting old, so no app is left to drift out of date.

Apps we've built

These are CarrySo's own products, published on Google Play under our developer account. Figures are taken from Google Play when this site was built; each card links to the case study.

Frequently asked questions

How long does it take to build a mobile app?

It depends mostly on scope: the number of distinct screens and flows, whether a backend is needed, and how many integrations there are. A focused MVP with one core workflow is far faster to ship than a multi-role platform. We give a timeline in the written scope after discovery, and we release early test builds so progress is visible.

How much does mobile app development cost?

Cost follows scope and complexity: number of features and screens, custom UI and animation, backend and admin needs, third-party integrations, supported platforms, and ongoing maintenance. We don't publish fixed prices, because two apps with the same name can differ by months of work. Share your idea through the contact form and we'll reply with questions and then an estimate.

Do you build iOS apps?

We build with Flutter, which compiles the same code base for iOS and Android. Our published portfolio is currently on Google Play. For an iOS release we add Apple Developer Program setup, iOS device testing and App Store review to the plan explicitly.

Can you take over an existing Flutter app?

Yes. We start with a code review covering architecture, dependencies, test coverage, crash reports and store policy status. Then we propose a plan to stabilise the app before adding features.

Do you publish the app to the store for us?

Yes. Store preparation is part of every project: listing text, screenshots, the privacy policy, the Data safety form, signed release builds and handling review feedback.

Guides on this topic

Mobile app development

How Much Does It Cost to Build a Mobile App?

What drives the cost of a mobile app: scope, backend, integrations, design, platforms and maintenance. How to estimate your app and what an honest quote includes.

MVP

How Long Does It Take to Build an MVP App?

A realistic MVP timeline for a mobile app: what fits in weeks, what pushes it to months, and how to scope a Flutter MVP that ships to real users fast.

Tell us what you want to build. We'll reply by email with questions, and then with a proposed scope and estimate.

Start a project Email carrysoofficial@gmail.com