Mobile resources for developers

A practical guide to building React Native apps the way the React Native and Expo docs recommend today. It covers project setup and upgrades, components and styling, lists, performance and threads, navigation and deep links, security and storage, accessibility, and testing and release, with short examples you can copy.

• Web
• Mobile
• Frontend

A mobile app security checklist for Android, iOS, Flutter and React Native apps, organised by the eight OWASP MASVS categories. Every check says how much it matters and how to verify it on a real build, using platform tools or the techniques in the OWASP Mobile Application Security Testing Guide.

• Mobile
• Security

A practical guide to building Flutter apps the way the Flutter and Dart teams recommend today. It covers Dart and null safety, widgets and build methods, app architecture and state, rendering performance, navigation and platform changes, accessibility, testing and release builds, with short Dart examples you can copy.

• Web
• Mobile
• Frontend

A step-by-step checklist for publishing a mobile app on the Apple App Store and Google Play for the first time, or for a client. It covers developer accounts, current build requirements, the review guidelines that cause most rejections, privacy labels and the Data safety form, store listing and screenshots, in-app purchase rules, testing tracks, crash reporting and phased or staged rollout, checked against Apple and Google documentation in October 2026.

• Career
• Mobile
• Freelancing

A quick-revision companion to the Sefism mobile roadmap, from your platform language to shipping in the stores: language essentials, UI and layout, state and navigation, networking and local data, device features and notifications, testing, performance and accessibility, and publishing and releases. It comes in Flutter, React Native, Android (Kotlin and Compose) and iOS (Swift and SwiftUI) editions, each concept with a short snippet and the classic mistake. Read a chapter to refresh a stage, or jump to one concept when you need it.

• Web
• Mobile
• Testing

A searchable library of screenshots and flows from real mobile and web apps, used by designers to see how established products handle onboarding, checkout, empty states and other patterns. The free tier is limited; paid plans unlock the full library.

• Frontend
• Web
• Mobile

A subscription backend for mobile apps that wraps Apple StoreKit and Google Play Billing, so you get purchases, restores, entitlements, paywalls and subscription analytics from one SDK. It is free until your app tracks $2,500 a month in revenue.

• Mobile

The official Android guide to selling one-time products and subscriptions through Google Play: the Play Billing Library, product setup in Play Console, backend verification with real-time developer notifications, and testing. Pair it with the Play service fee page, because fees changed in several markets in 2026.

• Mobile

Apple's official guide to selling digital content and subscriptions inside iOS apps with StoreKit: product types, subscription groups, offers, testing in the sandbox and App Store Connect setup. Read it with the App Store Small Business Program page, which halves the commission for most small developers.

• Mobile

An eight-stage plan for building a small product of your own and selling it, as a SaaS, a digital product such as a template or starter kit, or a mobile app. It covers choosing a painful problem, validating with interviews, a smoke test and pre-sales, building a small first version, getting paid from your country, pricing, positioning and launch, growth metrics, and support, legal basics and a keep, pivot or stop decision. It suits students and early-career engineers who can already build and want to learn the customer and money side. At the end you have a validated, launched product and the numbers to decide what to do next.

• Career
• Frontend
• Web
• Mobile

A seven-stage plan for building and shipping real Android and iOS apps with Flutter, React Native, Kotlin or Swift: your platform language, UI and layout, state and navigation, networking and offline storage, device features and notifications, testing, performance and accessibility, and publishing to Google Play and the App Store. It suits programmers who want to build for phones. By the end you have a multi-screen app that works offline, uses device features, is tested and accessible, and is live in a store test track with real users.

• Web
• Mobile
• Frontend
• Testing

A popular English channel for native Android development with Kotlin: Jetpack Compose, Kotlin Flows, MVVM architecture, testing, storage, security, Kotlin Multiplatform and Spring Boot with Kotlin. Philipp explains why code works, not just how. It suits Android learners past the basics and Kotlin developers who want production-quality habits.

• Web
• Mobile
• Testing
• Backend

The engineering blog of ASOS, the UK online fashion retailer, published on Medium. Posts cover Android clean architecture, demand forecasting benchmarks, QA engineering practice, measuring agility across large teams and AI-assisted development. It is useful for mobile developers who want a clear explanation of layered Android architecture, and for anyone curious how a large retailer organises engineering, though new posts now appear only a few times a year.

• System design
• Mobile

Shopify's engineering blog, known for keeping one of the largest Ruby on Rails applications running through flash sale traffic and for its work on Ruby performance. 2026 posts cover moving the Shop app from React Native to native, replacing Redis with MySQL for inventory reservations, clustering billions of products and building durable LLM agent harnesses. Frequent, practical and honest about trade offs.

• System design
• Backend
• Mobile

Apple's official rules for apps on the App Store, covering safety, performance, business and payments, design, and legal and privacy requirements, with a checklist of what to do before you submit. It is essential reading for any student or developer shipping an iOS, iPadOS or macOS app, because most rejections come from rules here: in-app purchase, privacy, account deletion, incomplete apps and minimum functionality.

• Career
• Mobile

Google's official help centre for publishing Android apps on Google Play: developer account setup, testing tracks, the closed testing requirement for new personal accounts, the Data safety form, store listings, policy compliance, releases and app quality monitoring. It is the authoritative reference when an app is rejected or a release is blocked, so read the relevant pages before launch week, not during it.

• Career
• Mobile

OWASP's mobile security project for Android and iOS. The MASVS standard defines what a secure app must do across storage, cryptography, authentication, networking, platform interaction, code, resilience and privacy, and the MASTG testing guide shows how to check each on a real device. Use it to decide where tokens and personal data may live, and as a security checklist before release.

• Mobile
• Testing

The official guides for Firebase, Google's app development platform and the backend many student mobile and web apps start on. It covers Authentication, Cloud Firestore and Realtime Database, Cloud Storage, Cloud Functions, Hosting, Cloud Messaging for push notifications, Crashlytics, Analytics and newer AI features, with setup for Android, iOS, web and Flutter. The docs are free; services have a free tier and pay-as-you-go usage beyond it.

• Mobile
• Backend
• Databases

The official Android developer guides and reference: Jetpack Compose UI, data and files, permissions, navigation, background work with WorkManager, camera, location, connectivity, testing, performance tools and releasing your app, plus guides for phones, tablets, foldables, Wear OS, TV, cars and XR. It suits developers who have finished a beginner course such as Android Basics with Compose and need accurate, current answers while building real apps.

• Mobile
• Testing

Google's recommended architecture for Android apps: separation of concerns, driving the UI from data, a single source of truth and unidirectional data flow, organised into a UI layer with ViewModels and UI state, a data layer with repositories, and an optional domain layer, with dependency injection through Hilt. It explains the reasoning behind the patterns Android Basics with Compose teaches, and it is what Android teams expect you to know.

• Mobile
• System design

Apple's official reference and guides for building apps on its platforms: Swift, SwiftUI, UIKit, SwiftData, Foundation, networking, notifications, location, testing, Instruments and app distribution. Tutorials get you started, but this is where iOS and macOS developers look things up once they are building their own app. Many framework pages include runnable sample code projects, and it is free to use without a paid developer account.

• Mobile
• Testing

Apple's official design guidance for apps on iPhone, iPad, Mac, Apple Watch, Apple TV and Vision Pro, organised into foundations, patterns, components, inputs and technologies. It covers layout, typography, colour, navigation, controls, privacy prompts, notifications and accessibility. Reading the relevant page before designing a screen helps developers avoid choices that make an app feel foreign on Apple platforms or cause problems in review.

• Mobile
• Frontend
• Web

Google's design system for Android, Flutter and web apps: foundations such as layout and accessibility, styles for colour, typography, shape, elevation, icons and motion, and a specification for every standard component. It includes dynamic colour, a Figma design kit and a theme builder. Developers who design their own screens can use it so apps look and behave as users expect, with sensible touch targets and contrast.

• Mobile
• Frontend
• Web

The official book on the Swift language, published free by the Swift project and updated with each language release. It explains optionals, value and reference types, closures, protocols, generics, error handling and concurrency clearly and precisely. It suits anyone learning Swift for iOS or server work, and those already writing SwiftUI who keep tripping over the language itself. Start with the guided tour, then use the rest as a reference.

• Mobile
• Programming