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Devsinn Technologies

Mobile app development

iOS and Android apps from one codebase

We build mobile apps with Flutter and FlutterFlow, so you launch on both stores faster and maintain one app, not two.

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  • Fixed price in GBP
  • UK GDPR-aware
  • You own the code
Developers testing a mobile app on phones and laptops

In short

Mobile app development is building apps for iPhone and Android devices. Devsinn uses Flutter and FlutterFlow to ship both platforms from one codebase, which usually cuts build and maintenance cost. We fix the price in GBP after discovery, handle App Store and Google Play submission, and support the app after launch. You own the code.

What you get

  • Both stores, one build

    iOS and Android from a single Flutter codebase.

  • Launch sooner

    FlutterFlow speeds up screens without losing custom code.

  • Native feel

    Smooth performance, device features and offline support.

  • Store-ready

    Submission, reviews and release notes handled for you.

Flutter, FlutterFlow or native: which should you choose?

FlutterFlow is fastest for standard app screens and MVPs, and exports real Flutter code. Flutter suits most business apps that need custom logic, performance and long-term maintenance. Fully native Swift and Kotlin apps make sense only for heavy device-specific features, games or very demanding graphics. We recommend the cheapest option that meets your needs.

Comparing mobile app approaches
ApproachBest forRelative costOne codebase
FlutterFlowMVPs, standard business appsLowestYes
Flutter (custom code)Most business and consumer appsMediumYes
Native (Swift and Kotlin)Heavy device features, gamesHighestNo, two apps

How much does a mobile app cost in the UK?

A FlutterFlow MVP typically starts from £9,000 + VAT. A custom Flutter app for iOS and Android usually starts from £18,000 + VAT, depending on features, integrations and back end. We fix the price after discovery and quote store fees, hosting and maintenance up front so the total cost is clear.

Indicative mobile app costs (GBP, + VAT)
ScopeTypical priceTypical timeline
FlutterFlow MVPFrom £9,0005 to 8 weeks
Custom Flutter app (iOS and Android)From £18,0008 to 14 weeks
App with complex back end and integrationsFrom £30,0003 to 5 months
Maintenance and store updatesFrom £450 a monthOngoing

Do you need a mobile app or a web app?

Choose a mobile app when users return often, need push notifications, the camera, location or offline access, or expect to find you in the app stores. Choose a web app when users visit occasionally or mainly on desktop. Many businesses start with a web app and add mobile once usage proves it.

  • Field teams, drivers and engineers: usually mobile, often offline.
  • Customers booking or ordering repeatedly: mobile pays off.
  • Occasional self-service or desktop-heavy work: start with web.

What happens at App Store and Google Play launch?

We prepare store listings, screenshots, privacy labels and data safety forms, run TestFlight and internal testing, then submit for review. Apple and Google reviews usually take a few days. We handle any review feedback, and you publish under your own developer accounts, so the app stays in your name.

How do you keep the app working after launch?

Apple and Google update their operating systems every year, and apps need regular updates to stay compatible and secure. Our maintenance plan covers OS updates, crash monitoring, dependency and security updates, and small improvements, so the app keeps working and keeps its store ratings.

How it works

  1. Free 20-minute call

    Your users, must-have features and whether mobile is the right call.

  2. Roadmap and prototype

    Clickable prototype, scope and a fixed price.

  3. Build

    Weekly test builds on your own phone through TestFlight and Play testing.

  4. Launch

    Store listings, submission and a monitored release.

  5. Support

    OS updates, crash fixes and new features in planned releases.

What it costs

Indicative prices in GBP, excluding VAT. We fix the price in writing after a short scoping call. Full price guide

FlutterFlow MVP

From £9,000+ VAT

International: From $11,500

  • iOS and Android
  • Core screens and login
  • Store submission

Custom Flutter app

From £18,000+ VAT

International: From $23,000

  • Custom logic and integrations
  • Offline and device features
  • Admin panel where needed

Maintenance

From £450+ VAT

per month

International: From $575

  • OS and security updates
  • Crash monitoring
  • Small improvements

A good fit if you

  • Businesses with field staff, drivers or engineers
  • Brands whose customers book or order repeatedly
  • Founders validating an app idea with an MVP

Not the right fit if you

  • Apps that only duplicate a website with no extra value
  • 3D games or graphics-heavy apps (a games studio fits better)
  • Launches without budget for annual store and OS updates

Questions people ask

Still unsure? Ask us on a free 20-minute call.

Is FlutterFlow good enough for a real business app?

Yes, for many apps. FlutterFlow produces genuine Flutter code, supports custom functions and integrations, and suits MVPs and standard business apps well. For complex logic or heavy customisation, we export to Flutter and continue in code, so you are not trapped by the platform.

How long does it take to build a mobile app?

A FlutterFlow MVP usually takes five to eight weeks. A custom Flutter app takes eight to fourteen weeks, and larger apps with complex back ends three to five months. Add a few days for store review at launch. You get weekly test builds throughout.

Do we own the app and its code?

Yes. The code is assigned to you on payment, and the app is published under your own Apple and Google developer accounts. If we use FlutterFlow, the project sits in your account too, with the exported code in your repository.

Can the app work offline?

Yes. We can store data on the device and sync it when a connection returns, which suits drivers, engineers and staff in poor signal areas. Offline support adds some complexity, so we scope exactly which features need it during discovery.

Is the app UK GDPR compliant?

We build with UK GDPR in mind: minimal data collection, clear consent, secure storage, encrypted traffic and accurate App Store privacy labels. We document what data the app collects and why, so you can update your privacy notice. Your organisation stays in control as data controller.

What are the ongoing costs of a mobile app?

Expect Apple's developer fee of about £79 a year, Google's one-off registration fee, hosting for the back end, and maintenance. Our maintenance plans start from £450 + VAT a month and keep the app compatible with each new iOS and Android release.

Can you take over an app built by someone else?

Usually, yes. We review the code, build setup and store accounts first, then give you a plain-English report and a plan to stabilise or improve it. If a rebuild is cheaper in the long run, we say so and explain why.

Related

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