Mobile App Development for UK Businesses: A Complete Guide

Mobile applications represent a significant investment for any UK business. Get it right and you've created a direct channel to your customers that drives engagement, loyalty, and revenue. Get it wrong and you have an expensive app that nobody downloads and fewer use.

This guide covers everything a UK business needs to know before commissioning a mobile app — from platform decisions to realistic budgets to the questions that determine whether your project succeeds.

iOS vs Android: Where Should You Start?

The UK smartphone market is split roughly 50/50 between iOS and Android, with iOS slightly dominant among higher-income demographics and Android stronger in the broader market.

For most UK business applications, the choice isn't either/or — you need both. The question is which to build first.

Start with iOS if: your target audience is higher-income professionals (banking, wealth management, premium B2C), your users are likely iPhone users (check your website analytics — what devices are your visitors using?), or you're targeting the US market alongside the UK.

Start with Android if: your app targets a broad consumer audience, you're building for markets where Android has higher penetration, or you're building for business or enterprise users who are on company Android devices.

In most cases, the recommendation is: build for both platforms simultaneously using a cross-platform framework (see below), which dramatically reduces the cost premium of supporting both.

Native vs. Cross-Platform: The Real Trade-offs

This is the most technically significant decision in mobile app development, and the answer has changed significantly over the last three years.

For most UK business mobile applications in 2026, React Native or Flutter is the right choice. The performance gap between cross-platform and native has narrowed significantly — both React Native and Flutter can achieve native-level performance for the vast majority of app types.

Native development only makes clear sense for: apps using cutting-edge platform features immediately on release, games with intensive rendering requirements, or apps with deep hardware integration (custom Bluetooth protocols, CoreML on-device, etc.).

React Native vs Flutter: Choosing Between the Two

If you've decided on cross-platform development, the next question is React Native vs Flutter:

React Native (Meta): Uses JavaScript/TypeScript, renders using native platform components. If you have a web application built with React, your team can share knowledge and potentially some code between platforms. Large ecosystem, mature tooling.

Flutter (Google): Uses Dart, renders using its own graphics engine (Skia/Impeller). Produces more visually consistent UIs across platforms. Currently seeing rapid adoption and has excellent performance characteristics.

Our current recommendation for most projects: React Native if your team has JavaScript/React experience, Flutter if starting from scratch with a team open to Dart. Both are production-ready and well-supported.

What Mobile Apps Cost in the UK

Mobile app costs are driven primarily by the number of screens, the complexity of backend integration, and whether you need custom design or can use a design system.

Note: these are build costs only. Add 15–20% per year for maintenance, plus ongoing infrastructure (APIs, databases, push notification services).

The cost difference between iOS-only and cross-platform (both iOS + Android) is roughly 30–40% — not double, because most of the logic and design work is shared.

The App Store and Play Store: What You Need to Know

Getting your app into the Apple App Store and Google Play Store involves review processes that can delay your launch if not planned for.

Apple App Store: review process takes 1–3 days for new submissions. Apple rejects approximately 30–40% of first submissions. Common rejection reasons: bugs (apps should be tested thoroughly before submission), privacy policy issues, misleading descriptions, and guideline violations. Budget 1–2 weeks of buffer in your launch plan for review iterations.

Google Play Store: review process is faster (typically same-day for established developer accounts) and rejection rates are lower. However, Google uses automated scanning that can flag certain permissions or code patterns, requiring justification.

Both stores require: a developer account (£25 one-off for Google, £99/year for Apple), privacy policy (mandatory for apps collecting any user data), app screenshots and descriptions in the store listing.

Common Mobile App Mistakes

Based on projects we've reviewed and inherited, these are the most common ways mobile app projects go wrong:

1. Designing for desktop first and adapting for mobile — mobile UX requires different design patterns from the start
2. Underestimating backend requirements — the backend API that your app calls is often as complex as the app itself, but frequently not scoped properly
3. Not testing on real devices across the market range — an app that works on the latest iPhone may have issues on older Android devices
4. Ignoring offline behaviour — mobile networks are unreliable; apps that don't handle connectivity loss gracefully create poor user experiences
5. Over-requesting permissions — users are increasingly privacy-aware; requesting camera, location, and contacts access without clear justification reduces install rates
6. Not planning for app updates — apps need updating as iOS and Android release new versions; budget for at least 2–3 update cycles per year

Technical Requirements Checklist for Commissioning a Mobile App

Before approaching a development agency, have answers to these questions:

• Which platforms are required at launch: iOS, Android, or both?
• What are the minimum supported OS versions? (Older OS = more testing, sometimes more development work)
• Does the app need to work offline? If so, which features?
• What external systems or APIs does the app need to integrate with?
• What authentication method will users use? (Email/password, social login, company SSO?)
• Does the app handle payments? (Apple and Google have strict rules about in-app payments)
• Does the app process personal or sensitive data? (GDPR implications)
• What analytics and user behaviour tracking do you need?