Mobile App Development Services in London

Mobile app development costs in the UK vary significantly based on complexity, platform, and features:

• Simple app (single platform, basic features, minimal backend): £3,000 to £10,000
• Mid-complexity app (iOS and Android, custom UI/UX design, API integrations, user accounts): £10,000 to £50,000
• Enterprise app (advanced security, multiple system integrations, admin dashboards, ongoing maintenance): £50,000 and above

Key factors that affect cost include the number of platforms (iOS only, Android only, or both), complexity of the design, number of features, backend infrastructure requirements, and whether ongoing maintenance is included.

Most professional agencies offer a free initial consultation and a detailed project scope document before any commitment is made.

Mobile app development timelines depend on the complexity of the project. A typical breakdown looks like this:

• Discovery and Planning: 1 to 2 weeks
• UI/UX Design: 2 to 4 weeks
• Development: 6 to 16 weeks depending on features and complexity
• Testing and Quality Assurance: 1 to 3 weeks
• App Store Submission and Launch: 1 to 2 weeks

As a general guide:

• A simple app can be built and launched in 6 to 10 weeks
• A mid-complexity app typically takes 3 to 5 months
• A large enterprise app can take 6 to 12 months or more

A reputable development agency will provide a detailed project timeline at the start of every engagement so you know exactly what to expect and when.

Native app development means building separate apps for each platform using platform-specific languages:

• iOS: Swift or Objective-C
• Android: Kotlin or Java

Native apps deliver the best performance, smoothest animations, and full access to device features like camera, GPS, biometrics, and push notifications. However, they require two separate codebases, which increases development time and cost.

Cross-platform development uses a single codebase that runs on both iOS and Android. Popular frameworks include:

• Flutter - known for near-native performance and expressive UI
• React Native - widely used, JavaScript-based, large developer community
• Xamarin - .NET based, preferred for enterprise applications

Cross-platform apps are typically 30 to 40% cheaper to build and maintain than two separate native apps. The trade-off is occasional limitations in accessing very platform-specific features, though these gaps have narrowed significantly in recent years.

Which is right for you? If budget and speed to market are priorities, cross-platform is usually the better choice. If performance and a premium user experience are critical - particularly for gaming, AR, or complex animations - native development is worth the extra investment.

Flutter is an open-source UI framework developed by Google that allows developers to build natively compiled apps for iOS, Android, web, and desktop from a single codebase using the Dart programming language.

Key reasons Flutter is widely used:

• Near-native performance - Flutter compiles to native ARM code, making it significantly faster than many other cross-platform frameworks
• Single codebase - one set of code runs on both iOS and Android, reducing development time and cost
• Rich UI components - Flutter has its own rendering engine (Skia/Impeller), giving developers full control over every pixel of the UI
• Hot reload - developers can see changes instantly without restarting the app, speeding up the development process
• Growing ecosystem - strong community support, extensive package library, and backed by Google

Flutter is particularly popular for startups and businesses that need a high-quality app on both platforms without the cost of building two separate native apps.

React Native is an open-source framework developed by Meta (Facebook) that allows developers to build cross-platform mobile apps using JavaScript and React.

Key differences between React Native and Flutter:

React Native is a strong choice when you want the app to feel native to each platform and your team already works in JavaScript. Flutter is preferred when you need a highly custom UI that looks identical across platforms and want better long-term performance for complex interfaces.

Publishing on both major app stores requires meeting specific technical and policy requirements:

Apple App Store:

• Requires an Apple Developer account - annual fee of £79 per year
• App must be reviewed and approved by Apple, which typically takes 1 to 3 business days
• Must comply with Apple's Human Interface Guidelines and App Store Review Guidelines
• Requires specific assets including app icons, screenshots for multiple device sizes, and a privacy policy

Google Play Store:

• Requires a Google Play Developer account - one-time registration fee of £19
• App review typically takes a few hours to 3 business days for new apps
• Must comply with Google Play's Developer Policy
• Requires a privacy policy, content rating questionnaire, and store listing assets

Common reasons apps get rejected:

• Incomplete or misleading app descriptions
• Privacy policy missing or insufficient
• App crashes or has major bugs during review
• Violates platform content or monetisation policies

A professional development agency will handle the full submission process, prepare all required assets, and ensure the app meets all technical and policy requirements before submission.

Yes - ongoing maintenance is essential for any mobile app. Here is why:

• Operating system updates - Apple and Google release major iOS and Android updates every year. Apps that are not updated to remain compatible will break or be removed from the app stores
• Security patches - new vulnerabilities are discovered regularly. An unmaintained app becomes a security risk for both your business and your users
• App store policy changes - both Apple and Google frequently update their developer policies, requiring app updates to remain compliant
• Bug fixes - issues that were not caught during testing often surface once real users interact with the app at scale
• Performance optimisation - as your user base grows, backend infrastructure and app performance need to be monitored and scaled accordingly
• Feature updates - user expectations evolve. Regular updates keep your app competitive and retain user engagement

As a general rule, budget approximately 10 to 20% of the original development cost per year for maintenance and updates. Many agencies offer monthly retainer packages that cover hosting, monitoring, updates, and priority bug fixes.