Ahmed B.

I build the expensive parts of a mobile app: billing that doesn't leak, AI that doesn't burn your budget, and code that still works six months after launch. Most apps don't break on launch day. They break three months in: the subscription that silently stops renewing, the AI call costing ten times what it should, the crash that only fires on one OEM's build. That's my work. ✅ Google Play Billing, Stripe and Paymob running in production ✅ Cut LLM prompt tokens ~70% with a TOON encoder I wrote in Kotlin, at a ~90% cache hit rate ✅ A full consumer app shipped at 4MB, detail screens rendering in under a second ✅ Android 16 Live Updates in production, an API almost nothing on the Play Store uses yet I work to your hours: US, UK or EU, and I reply within four hours. 𝗪𝗛𝗔𝗧 𝗜 𝗕𝗨𝗜𝗟𝗗 - Native Android in Kotlin and Jetpack Compose, Material 3, clean architecture - Kotlin Multiplatform, one codebase running on both Android and iOS - iOS: shipped iOS targets, App Store release, and Swift or SwiftUI work on existing apps - Android TV: shipped and tested on real hardware, including cross-app deep linking - Payments: Google Play Billing, subscriptions, free trials, server-side verification, Stripe, Paymob - Firebase and Appwrite backends, Cloud Functions, push, Crashlytics, React dashboards - Store release, and rescuing inherited Flutter, React Native and AI-generated code 𝗔𝗜-𝗡𝗔𝗧𝗜𝗩𝗘 𝗠𝗢𝗕𝗜𝗟𝗘 𝗔𝗣𝗣𝗦 Built in Kotlin and Swift, not a WebView around someone else's chat page. Wiring a model into an app is the easy half. Keeping it fast and cheap once real users hit it is what decides whether it ships. - AI integration into new or existing apps: OpenAI, Gemini, Groq, with automatic provider failover - Token cost engineering: I wrote a TOON encoder and decoder in Kotlin from the spec, cutting prompt tokens up to 70% against JSON - Prompt and response caching tuned to a ~90% hit rate - Streaming responses, multi-turn sessions with history pruning - The billing underneath it: credits, packages, subscriptions, server-side verification 𝗪𝗛𝗔𝗧 𝗜'𝗩𝗘 𝗦𝗛𝗜𝗣𝗣𝗘𝗗 Arcadia, an AI game tracker on Google Play. Multi-provider LLM chat with failover, word-by-word streaming, and months spent on what it costs to run: a hand-written TOON codec, aggressive caching, no API keys in the binary. The whole app installs at 4MB and detail screens render in under a second. Winner of the Android developer track in Egypt's national DEPI programme. FlexPing, for a UK founder serving Amazon Flex drivers. Empty repo to a live, paying product on Google Play: monthly and yearly subscriptions with a free trial, server-side receipt verification through Cloud Functions, a foreground service that survives Android's battery optimizer, and a cancellation flow that protects revenue rather than leaking it. PixelOne, a multi-tenant restaurant ordering and loyalty platform in Kotlin Multiplatform, running on Android and iOS from one codebase with a React admin dashboard. Every order is re-priced and every balance verified server side. Live order tracking runs on Android 16's Live Updates API, and the product screen uses a Compose shared element transition. 𝗛𝗢𝗪 𝗜 𝗪𝗢𝗥𝗞 I use Claude Code and Cursor where they help, and I know where they stop. Android's newest APIs barely exist in any model's training data, so on anything current the tools guess, and much of what's published for them was generated rather than written. That gap is where I do my best work. I own the design and the backend too, so when a subscription doesn't renew or a background job dies silently on a Samsung device, that's mine to fix, not a ticket I hand back. 𝗪𝗛𝗢 𝗜'𝗠 𝗙𝗢𝗥 Your app takes payments, or needs to. Or you want AI in it and need someone who can build the metering and billing underneath, not just the API call. I'm the wrong hire for cheapest-bidder work, or for closing tickets rather than owning outcomes. Tell me what you're building and I'll give you an honest read on scope, stack and timeline. 𝗥𝗢𝗟𝗘𝗦 𝗜 𝗛𝗜𝗥𝗘 𝗜𝗡𝗧𝗢 Android Developer, Android App Developer, iOS Developer, Mobile App Developer, Kotlin Developer, Swift Developer, AI Developer, AI Engineer 𝗔𝗣𝗣𝗦 𝗜 𝗕𝗨𝗜𝗟𝗗 Android App Development, iOS App Development, Cross-Platform App Development, Mobile App Development, Android TV Apps, AI-Native Apps, AI Integration, AI Chat Apps, Subscription Apps, SaaS Mobile Apps, MVP Development, Legacy App Rescue 𝗧𝗘𝗖𝗛 𝗦𝗧𝗔𝗖𝗞 Android, Kotlin, Jetpack Compose, Java, Material 3, Room, WorkManager, Android TV iOS, Swift, SwiftUI, Xcode, Kotlin Multiplatform, Flutter, React Native OpenAI, Gemini, Groq, LLM Integration, Prompt Engineering, Prompt Caching, Token Optimization Google Play Billing, In-App Subscriptions, Server-Side Receipt Verification, Stripe, Paymob Firebase, Cloud Functions, FCM, Crashlytics, Appwrite, Cloudflare Workers, Node.js, TypeScript React, Vite, Figma, UI/UX Design, CI/CD, Play Console, App Store