A mobile app is judged in seconds — and deleted just as fast. Billow designs and builds native and cross-platform mobile apps that are fast, intuitive and genuinely useful, from first sketch through app store launch and the support that keeps them there.
Mobile app development is the design, building and shipping of applications that run on smartphones and tablets — iOS and Android — covering UX, front-end and back-end development, API integration, testing, app store release and ongoing support. The bar is high: on a phone, an app has seconds to prove it’s worth keeping.
Mobile is unforgiving. Users expect apps to be fast, intuitive and reliable, and they’ll abandon anything that isn’t — a clunky flow, a slow screen, a crash — without a second thought. Building a mobile app that survives that scrutiny takes real design and engineering, not just porting a website into a smaller frame.
Billow builds mobile apps that earn their place on the home screen. We design the experience around how people actually use their phones, build native (Swift, Kotlin) or cross-platform (React Native, Flutter) depending on what fits, integrate the backends and APIs behind them, test thoroughly, and ship to the app stores — then keep the app current as devices and operating systems move on.
Our mobile app development services cover the whole build — design, development, release and the support that keeps the app healthy.
Design the experience around real user needs and mobile behavior — prototyped and validated before we build.
High-performance native apps in Swift and Kotlin, with full access to device features where it counts.
One codebase for both platforms with React Native or Flutter — faster and cost-effective for most apps.
The services, APIs and data behind the app — built and connected so the app actually does something.
Thorough testing across devices, and managed submission to the Apple App Store and Google Play.
Ongoing updates for new OS versions, devices, fixes and features — so the app keeps working and improving.
Users delete apps that are slow, confusing or unreliable without a second thought. We design and build for that scrutiny, so your app is one people keep and use.
We design around how people actually use phones — fast, intuitive flows that survive real-world use.
Native or cross-platform, chosen for your performance, budget and roadmap — not a one-size default.
Thorough QA across the devices your users carry, so launch day isn’t a bug hunt.
Ongoing support means your app doesn’t break with the next OS release or quietly fall behind.
We build native and cross-platform — recommending the right approach for your app, not forcing one.
SWIFT
Native iOS apps in Swift — fast, polished and fully at home on Apple devices.
Kotlin
Native Android apps in Kotlin — performant and consistent across the Android ecosystem.
REACT NATIVE · FLUTTER
One codebase for both platforms — faster and cost-effective, ideal for most apps.
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We design and prototype the experience — validating flows before a line of production code.
We build the app (native or cross-platform) and the backends and APIs behind it, in iterations.
We test across devices and ship to the App Store and Google Play — managing the release cleanly.
We maintain and improve the app — OS updates, fixes and new features — so it stays healthy.
Mobile app development is the process of designing, building and shipping applications that run on smartphones and tablets — iOS and Android. It spans the whole journey: user experience design, front-end and back-end development, integration with services and APIs, testing, app store release, and ongoing maintenance. The goal is an app that’s fast, reliable and genuinely useful on a small screen.
It depends on your needs. Native apps (Swift for iOS, Kotlin for Android) give the best performance and access to device features, but mean two codebases. Cross-platform frameworks (React Native, Flutter) build both platforms from one codebase — faster and cheaper, and excellent for most apps. We recommend the approach that fits your budget, performance needs and roadmap, rather than defaulting to one.
Yes. We build native iOS and native Android apps, and cross-platform apps that target both from a single codebase. Whichever route fits, we deliver a consistent, high-quality experience across the devices your users actually carry.
It depends on scope, but a focused first version (MVP) can often reach the app stores in a few months, with more complex apps taking longer. We work iteratively — designing and shipping a strong core first, then building on it — so you get something real in users’ hands sooner rather than waiting for everything at once.
Yes. Mobile apps need ongoing care — OS updates, new devices, bug fixes and new features. We provide maintenance and support that keeps your app compatible, secure and improving, so it doesn’t break with the next iOS or Android release or slowly fall behind.
Mobile apps are part of a wider application practice. These connect to them most closely.
The full practice this sits within — modernization, custom development, APIs, QA and product management.
Mobile is often one channel of a bigger custom build — web, mobile and APIs from one team.
Every app needs a backend — the APIs and integrations that power the app live here.
Tell us the app you have in mind — or the one that isn’t landing — and we’ll show you how we’d design and build it to earn a place on the home screen.
