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I am a senior software developer/architect with over 15 years of professional experience. I bring deep expertise in building and delivering complex systems, ranging from back-office applications to real-time processing of high-volume data. I have built and maintained distributed systems across various domains, like fintech, iGaming, data privacy, IoT and large online marketplaces. I use AI coding tools (mostly Codex and Claude Code so far) all the time and find them very effective for accelerating development. Furthermore, I worked on integrating LLMs into an open-source coding assistant, which gave me practical familiarity not only with using AI-powered development tools, but also with how these tools work internally (context selection, orchestration of sub-agents, tools integration, MCP, etc). I look forward to the possibility of discussing how my background fits your current needs.

I help founders and businesses launch new digital products, take over existing codebases, and rescue applications that have become difficult to maintain. ✱ 15 years of software engineering experience, from startups to large technology companies ✱ 8,800+ tracked hours on Upwork with consistent 5-star feedback ✱ Tens of designed and delivered mobile products from initial architecture to store release and long-term maintenance I can help you with: 🔹 MVP and production app development from scratch 🔹 Flutter apps for Android, iOS, web, and desktop 🔹 Native Android development with Kotlin and Jetpack Compose 🔹 Full-cycle delivery: planning, design support, architecture, development, testing, and release 🔹 Mobile apps for existing websites, SaaS platforms, and APIs 🔹 Existing project takeover, modernization, and long-term maintenance 🔹 Crash fixes, broken builds, performance issues, and release blockers 🔹 Firebase, APIs, payments, subscriptions, push notifications, analytics, and AI features 🔹 Google Play, App Store, web, and desktop deployment You will receive clear milestones, regular test builds, daily progress reports, and early communication about risks or scope changes.

Software engineer specialized in the development of native client applications for REST web services with most of the experience in Android technology stack. Developing all layers of client applications, including JSON API integration, authentication mechanisms, and user interface elements. Extensive experience in using RxJava and EventBus library.

40 Projects Completed | 5 start rating | 100% Job Success Score | Top Rated 🏅 Senior Mobile Developer with experience architecting and delivering complex, business-aligned mobile-first systems and MVPs - taking full ownership from initial concept through scalable production using AI tools like Claude and Gemini for accelerated development. Specialised in both Android and iOS Native for maximum performance and the smoothest app experience with pixel-perfect UIs. Clients rely on my business-first approach: rapid launches powered by intelligent AI workflows, strategic guidance rooted in clean, robust code, and scalable technology that evolves with their long-term goals. 🚀 Tech Stack & Tools: 🛠️ AI & AI Integration: Gemini API, Claude API, OpenAI API (ChatGPT) AI-powered feature development and smart app integration 🛠️ Mobile Development: Kotlin, Jetpack Compose, Swift, SwiftUI Native Android & iOS development 🛠️ Backend & APIs: Firebase (Auth, Firestore, Cloud Functions), REST APIs, third-party integrations, deep linking, push notifications 🛠️ Architecture & Engineering: Clean Architecture, MVVM, performance optimization, scalability, App publishing (Google Play & App Store) 🛠️ Product Design: Figma Pixel-Perfect UI implementation, Figma to Code Why Partner with me? I will take you all the way from idea to first revenue, so you don't juggle specialists - perfect for any founder needing rapid, scalable MVPs that support marketing, analytics & growth. 100% IP handoff, fluent English, and collaborative via Slack/Jira. Let’s catch up and focus on what matters for your first release. Nikola Gocić ___________________________________________________ EXPERTISE: Native Android Development | Native iOS Development | Kotlin | Jetpack Compose | Swift | SwiftUI | Firebase Integration | AI Integration | OpenAI | Gemini | Claude | REST API Integration | Clean Architecture | Figma to Code | Push Notifications | Deep Linking | App Publishing | Google Play Store | Apple App Store | Mobile UI/UX Design

🚀 Senior Mobile Developer | Flutter Expert I help startups and businesses build scalable, production-ready applications — combining mobile development, backend systems, and AI-powered features. With 6000+ hours billed, 60+ successful projects, and 10+ years of experience, I deliver high-quality products that are reliable, scalable, and aligned with real business goals. ⸻ 💡 What I do: • 📱 Build high-performance mobile apps with Flutter • ⚙️ Develop robust backends (Node.js, APIs, real-time systems) • ☁️ Set up cloud infrastructure & DevOps (Cloudflare, CI/CD, performance optimization) • 🤖 Integrate AI into products (LLMs, automation, intelligent workflows) • 🔗 Deliver full-cycle development: from idea → architecture → production I specialize in building modern applications enhanced with AI — from smart assistants and content generation to automation tools and AI-driven features. ⸻ 🛠 Tech Stack: Mobile: Flutter (Dart), Bloc, Riverpod, GoRouter, Clean Architecture Backend: Node.js, Express, REST APIs, WebSockets AI & Automation: OpenAI, LLM integrations, prompt engineering, AI workflows Database: Supabase, Firebase, PostgreSQL, Drift DevOps & Cloud: Cloudflare, CI/CD, deployments, caching & performance optimization Integrations: Payments, push notifications, analytics, third-party APIs ⸻ 🏆 Why clients choose me: • 🚀 Top Rated on Upwork with proven track record • 💬 Clear, fast, and proactive communication • 🧠 Product thinking — not just coding • ⚡ Fast delivery without sacrificing quality • 🧪 Clean, maintainable code with test coverage • 📈 Performance-focused approach • 🔄 Reliable long-term collaboration • 💰 100% money-back guarantee if expectations aren’t met ⸻ If you’re looking for a developer who can build not just an app, but a complete AI-powered product — I’m ready to help. Let’s build something impactful

I help companies build fast, reliable, and maintainable software with Rust and C++ across desktop, mobile, and backend environments. My focus is on performance-critical applications, native systems, and cross-platform products that need to work cleanly on Windows, macOS, Linux, iOS, and Android. I’m comfortable taking a project from architecture and implementation to debugging, optimization, release, and long-term maintenance. What I can help with: Rust and modern C++ development Cross-platform desktop and mobile apps Native libraries, SDKs, and system-level components Performance optimization and memory/concurrency issues API integration and backend connectivity Codebase refactoring, stabilization, and bug fixing Build systems, CI/CD, and release workflows I care about writing clean code, communicating clearly, and delivering solutions that are practical in production, not just technically interesting. Whether you need a new product built from scratch, a legacy C++ codebase improved, or a Rust migration done safely, I can help move it forward. If your project needs strong native engineering with a product mindset, I’d be glad to work with you.