Mobile app development is the process of planning, designing, building, testing and publishing an application for Android phones, iPhones or both, then maintaining it after launch. A successful app solves one clear, repeated task for its users better than a website can, for example through offline access, notifications, the camera or location. Before committing to a build, it is worth confirming that the task genuinely needs an app, because a fast mobile website is cheaper to build and easier for customers to find.
App or mobile website: which do you need?
An app makes sense when people will use it often and it needs features a browser handles poorly. A mobile website or progressive web app is usually the better first step when people visit occasionally or mainly need information.
- Choose an app for frequent use such as ordering, booking, tracking or learning, and for features like push notifications, offline mode, payments stored on the device, the camera, GPS or Bluetooth.
- Choose a mobile website when customers mostly research, compare or enquire, and when being found through Google matters more than repeat use.
Native, cross-platform or hybrid
There are three main ways to build an app, and the choice affects cost, speed and long-term upkeep:
- Native apps are built separately for each platform, in Kotlin for Android and Swift for iOS. They give the closest fit with each operating system and the earliest access to new features, but you maintain two codebases.
- Cross-platform apps share one codebase for both platforms using frameworks such as Flutter or React Native. They suit most business apps and usually cost less to build and maintain.
- Progressive web apps are websites that can be installed on the home screen and work offline. They avoid app-store review but have more limited access to device features, especially on iPhones.
The stages of an app project
- Discovery: define the users, the core task and the one measure that shows the app is working, such as weekly active users or repeat orders.
- Scope a first version: a minimum viable product (MVP) with only the features needed for that core task.
- UX and UI design: wireframes and clickable prototypes, tested with real users before development starts.
- Development: the app itself, plus the backend, database, admin panel and APIs it relies on.
- Testing: functional, performance and security testing on a range of real devices and operating-system versions.
- Store submission: listings, screenshots, privacy declarations and review by Apple and Google.
- Launch and iteration: analytics, crash reporting and regular updates based on how people actually use the app.
App store requirements to plan for
Publishing has its own rules and costs, and they change over time. As of 2026:
- Developer accounts: Google Play charges a one-time registration fee of US$25, and the Apple Developer Program costs US$99 per year.
- Testing before launch on Google Play: new personal developer accounts created after 13 November 2023 must run a closed test with at least 12 testers, opted in continuously for 14 days, before applying for production access. Organisation accounts follow a different verification route.
- Target Android version: from 31 August 2026, new apps and updates submitted to Google Play must target Android 16 (API level 36) or higher, so older projects may need updating before they can ship.
- Privacy disclosures: both stores require a privacy policy and a declaration of what data the app collects, shown to users as Google Play’s Data safety section and Apple’s privacy labels.
- App review: both stores review every new app and update, and reviewers need a working demo login for any app that requires an account.
Registering the developer accounts in your business’s name, rather than the developer’s, keeps ownership of the app with you.
What affects the cost and timeline of an app
- The number of screens and user roles, such as customer, staff and admin.
- Backend complexity: user accounts, payments, real-time updates, chat or maps.
- Integrations with existing systems such as a CRM, ERP, POS or website.
- Whether you build native apps for both platforms or one cross-platform app.
- Design depth, accessibility requirements and the range of devices to support.
- Ongoing costs after launch: hosting, third-party services, operating-system updates and new features.
A useful quote separates the first version from later phases and states what post-launch support includes. A practical rule is to budget each year for maintenance, because both Apple and Google release new operating-system versions annually.
Measuring whether an app is working
Downloads alone say little. The metrics that show real value are:
- Retention: the share of users still active after 1, 7 and 30 days.
- Active users: daily and monthly active users, and the ratio between them.
- Core task completion: orders placed, bookings made or lessons finished.
- Stability: crash-free sessions and app-store ratings and reviews.
Getting people to install the app
An app needs its own marketing plan. App store optimisation (a clear title, keyword-relevant description, strong screenshots and steady reviews) helps people find it inside the stores, while your website, social media and paid campaigns bring in new users. Planning these channels before launch avoids an app that works well but that few people know exists.