Nice to meet you 🎨✨ I'm Kostiantyn, a UI UX designer, product designer, UIUX designer, and web designer specializing in Mobile App Design, Web App Design, SaaS platforms, Dashboard Systems, and AI Products. As a figma specialist and landing page designer, I help startups and founders create user-friendly digital products with strong user experience, intuitive interfaces, and development-ready systems built on conversion rate optimization principles. With 600+ projects delivered across Mobile Apps, Web Apps, SaaS Platforms, Ecommerce, AI Products, Healthcare, Marketplaces, Dashboards, and Fintech - I work as a UI UX designer, web designer, graphic designer, saas designer, and landing page designer who understands the full picture from first wireframe to final handoff. ✅ What I do as a UI UX Designer, Web Designer, and Product Designer ❇️ Mobile App Design & Mobile UI UX As a mobile app ui ux designer and UI UX designer, I design for iOS and Android - covering onboarding flows, mobile ui ux navigation, and retention-focused mobile app design. Every mobile app design I deliver as a figma app designer is grounded in conversion rate optimization and real user behaviour. My mobile ui ux work spans healthtech, fintech, edtech, and marketplace products. Strong mobile app design requires both UIUX designer thinking and graphic designer craft working together. As a UIUX designer and saas designer with mobile experience, I treat every mobile app design project as a product problem first. ❇️ UI UX Design for SaaS & Web Apps As a SaaS designer, UIUX designer, and product designer, I build interfaces for analytics platforms, admin panels, and complex dashboards. My saas designer approach combines ux designer strategy with figma ui ux execution - delivering scalable systems. Whether you need a ui ux designer saas, ui ux dashboard, or full web design rebuild, I deliver as a ui ux designer figma and ui ux designer react specialist. Every saas designer engagement starts with a ux designer audit before any screen is touched. ❇️ Figma Design, Prototyping & Design Systems As a figma designer, figma ui designer, and UIUX designer, I deliver high-fidelity wireframes, prototypes, and figma ui design systems. I handle figma to webflow, figma to react, figma to wordpress, figma to shopify, and figma to next handoffs. Every figma app designer deliverable and figma landing page is built for developers to implement without guesswork. Whether you need a figma designer for a web design project or a figma ui designer for a full design system - I deliver. ❇️ Web Design, Website Design & Landing Pages As a web designer, website designer, and landing page designer, I create conversion rate optimization focused web design for SaaS, ecommerce, and startups. My web design spans wordpress website design, webflow ui ux, shopify website design, and wix web design - always delivered as a ui/ux web designer and website designer. As a landing page designer, I apply conversion rate optimization to every layout, CTA, and visual hierarchy. Every website design I deliver as a website designer is built to convert - because a landing page designer who ignores conversion rate optimization is just making art. Website design, web design, and website designer work are at the core of every engagement I take as a web designer. ❇️ Graphic Design & Visual Identity As a graphic designer, UI UX designer, and web designer, I cover logo design, brand identity, and visual systems. Strong graphic designer work is built into every product. Whether you need a graphic designer for a product launch, a web designer for website design, or a figma web designer for a landing page designer engagement - I bring the same graphic designer craft and UIUX designer discipline to every project. ❇️ UX Research & Information Architecture As a ux designer and product designer, I map user journeys, define information architecture, and build user flows that reduce friction. My ux designer process covers research, wireframing, and usability testing - giving every UI UX designer decision a strategic foundation. 📊 Results ✔️ 200+ projects as a UI UX designer, SaaS designer, web designer, UIUX designer, and graphic designer ✔️ Mobile app design for iOS & Android with mobile ui ux systems and figma app designer handoffs ✔️ Saas designer and ui ux designer saas work across dashboards and B2B platforms ✔️ Figma to react, figma to webflow, figma to wordpress, figma to shopify across 50+ products ✔️ Landing page designer work with proven conversion rate optimization results for SaaS and ecommerce ✔️ Graphic designer and website designer web design work across startup brands ✔️ Conversion rate optimization and website designer expertise across 50+ web design and landing page projects Have a product idea? Let's connect 🤝📩 and turn it into something people enjoy using ✨ Last updated: 30.06.2026

🏆 Forbes Tech Council Member · Harvard Speaker · 500k+ Users Served · $2B+ Automated I don't just ship code, I build the products users open every morning and the systems companies depend on to run. As a Lead AI Engineer, Full-Stack Developer, and Fractional CTO, I work across the full stack, from pixel-perfect mobile apps to AI backends processing billions in transactions. Whether you need a focused developer to ship fast, or an experienced technical leader to architect something that lasts, I've done both and I know exactly how to make it work for you. Why Clients Keep Coming Back →Forbes-Recognized AI Engineering – Tech Council member for ethical AI that actually works in production →Full-Stack from Day 1 – React Native, Next.js, MERN, WordPress, Node.js, built for real scale →Rapid MVP Launches – Ship production-ready MVPs fast using Lovable.dev, Replit, Base44 & more →AI That Drives Revenue – Not demos, live LLM integrations, automation pipelines, and intelligent systems →Lead Engineer Mindset – Clean architecture, scalable systems, and code your next developer will thank me for →Fractional CTO Expertise – Strategic tech roadmaps without the $300k/yr price tag 🚀 Signature Builds •Vidan AI – AI-powered video intelligence platform processing thousands of hours of content daily •Finance AI – Automated banking system handling $2B+ in annual transactions with zero downtime •Sally AI – Enterprise AI assistant deployed across 500k+ employees; highest retention in its category •Machine AI – Predictive maintenance platform detecting factory breakdowns 3 days in advance ⚡ Rapid MVP & No-Code/Low-Code Builds Need something live fast? I use the best modern tooling to get you from idea to deployed in days, not months: •Lovable.dev – AI-powered full-stack app generation; I take it further with custom logic & integrations •Replit – Collaborative rapid prototyping and cloud-hosted MVP builds •Base44 – Internal tools and ops dashboards built in hours, not weeks •Bolt.new / v0.dev / Cursor – AI-assisted development for 3-10x faster delivery on web & mobile Whether you want a traditional build or a blazing-fast MVP, I speak both languages fluently. 📱 Mobile & Web Development •React Native — cross-platform apps that feel genuinely native on iOS and Android •Next.js & React — SEO-optimized, blazing-fast web apps with flawless UX •MERN Stack — MongoDB, Express, React, Node.js end-to-end •WordPress — from blog to enterprise engine, custom plugins, WooCommerce, headless CMS •PWAs, real-time apps, WebSocket integrations 🧠 AI & Automation •LLM integration & fine-tuning (GPT-4, Claude, Gemini, open-source models) •Custom AI agents & autonomous workflow automation •Intelligent chatbots with contextual memory & multi-turn NLP •Predictive analytics & ML pipelines (PyTorch, TensorFlow, Scikit-learn) •RAG systems, vector databases, AI-powered search •Process automation that eliminates bottlenecks and reduces headcount costs 🔧 Backend, Infrastructure & DevOps •RESTful & GraphQL API design and architecture •Microservices and event-driven architecture •AWS, Azure — cloud-native deployments and optimization •Docker, Kubernetes, CI/CD pipelines (GitHub Actions, Jenkins) •Database architecture: PostgreSQL, MongoDB, Redis, MySQL •Security audits, performance optimization, compliance ⭐ What Clients Say "Hadi rebuilt our entire platform. What used to take our team all day now finishes by 3 PM. Seven projects and counting, he's family." — Anna R., E-commerce Founder "Delivered two weeks early. The code was so clean our engineers applauded. Users loved the interface from day one. Best technical decision we ever made." — Danny P., HealthTech CEO ✅ Currently Accepting •Full-Stack Web & Mobile Development (React Native, Next.js, MERN, WordPress) •AI Integration & Intelligent Automation Projects •Rapid MVP Builds (Lovable.dev, Replit, Base44, traditional dev) •Lead Engineer & Technical Architecture Roles •Fractional CTO & Advisory Engagements (3-month minimum) Limited to 5 active projects. First-come priority to the most exciting, high-impact work. ────────────────────────────────────── → Message me "BUILD" for a free 20-minute strategy call ← ────────────────────────────────────── I don't just write code, I engineer products that users love and businesses can't live without. ________________________________________ Keywords: Lead Engineer, Full Stack Developer, AI Engineer, Solutions Architect, Fractional CTO, LLM Integration, React Native, Next.js, MERN Stack, Node.js, Python, WordPress Development, Machine Learning, NLP, Chatbot Development, DevOps, AWS, Enterprise AI, Process Automation, Forbes Tech Council, Mobile App Development, Web Development, Technical Leadership

We’re a two-person development team passionate about transforming ideas into fully functional, high-quality mobile apps. Over the past years, we’ve delivered 20+ successful apps across different industries from finance and real estate to on-demand services and booking systems. What makes us different: - Clear communication and quick delivery - Modern, clean UI/UX design - Scalable and maintainable code - Full project support: from design to deployment Tech stack: Flutter, Kotlin, Java, Swift, Dart, Firebase, MongoDB, REST APIs, Figma, node.js Whether you’re a startup or a company looking to upgrade your app we’ll make sure you get a smooth, reliable, and beautiful product. Let’s discuss your idea today we respond within a few hours.

⭐⭐⭐ "Zubair built a P2P fintech platform for us that helped us secure €100M in funding. His technical expertise, architecture decisions, and product thinking were instrumental to our success." Need a senior software engineer with 12+ years of experience building 𝐅𝐢𝐧𝐓𝐞𝐜𝐡, 𝐒𝐚𝐚𝐒, 𝐌𝐚𝐫𝐤𝐞𝐭𝐩𝐥𝐚𝐜𝐞𝐬, 𝐀𝐈, 𝐚𝐧𝐝 𝐌𝐨𝐛𝐢𝐥𝐞 𝐀𝐩𝐩𝐥𝐢𝐜𝐚𝐭𝐢𝐨𝐧𝐬? Let's talk. I help startups and enterprises transform complex ideas into secure, scalable, production-ready software. Whether you're building an MVP, rescuing a struggling project, or scaling an existing platform, I can help. 𝐖𝐡𝐚𝐭 𝐈 𝐁𝐮𝐢𝐥𝐝: ✔ FinTech & Digital Banking Solutions ✔ Digital Wallets & Payment Platforms ✔ Loan & Lending Platforms ✔ Investment & Wealth Management Systems ✔ Personal Finance Applications ✔ Insurance & InsurTech Platforms ✔ Marketplace & Booking Platforms ✔ AI Agents & Workflow Automation ✔ Enterprise SaaS Platforms ✔ Enterprise CRM & ERP Systems 𝐈𝐧𝐝𝐮𝐬𝐭𝐫𝐢𝐞𝐬 𝐈'𝐯𝐞 𝐖𝐨𝐫𝐤𝐞𝐝 𝐈𝐧 💳 𝐅𝐢𝐧𝐓𝐞𝐜𝐡 𝐚𝐧𝐝 𝐁𝐚𝐧𝐤𝐢𝐧𝐠 Digital wallets, mobile banking, payments, QR payments, lending, KYC/KYB, AML, Open Banking, wealth management, brokerage integrations, Stripe, Plaid, compliance systems, and financial analytics. 🚀 𝐒𝐚𝐚𝐒 & 𝐄𝐧𝐭𝐞𝐫𝐩𝐫𝐢𝐬𝐞 AI Agents, Voice AI, RAG applications, workflow automation, document intelligence, recommendation engines, conversational AI, and enterprise AI platforms. 🤖 𝐀𝐈 𝐚𝐧𝐝 𝐀𝐮𝐭𝐨𝐦𝐚𝐭𝐢𝐨𝐧 AI Agents, Voice AI, RAG applications, workflow automation, document intelligence, recommendation engines, conversational AI, and enterprise AI platforms. 𝐓𝐞𝐜𝐡𝐧𝐢𝐜𝐚𝐥 𝐄𝐱𝐩𝐞𝐫𝐭𝐢𝐬𝐞 I specialize in production-grade software using: React, Next.js, Angular Node.js, NestJS, Python, .NET React Native & Flutter PostgreSQL, SQL Server, MongoDB AWS, Azure, Docker, Kubernetes OpenAI, Claude, LangChain, RAG Stripe, Plaid, Open Banking APIs Twilio, Firebase, GraphQL & REST APIs 𝐇𝐨𝐰 𝐈 𝐖𝐨𝐫𝐤 I don't just write code. I partner with clients to make the right technical and product decisions. Every project starts with understanding your business goals before designing an architecture that is scalable, secure, and built to last. 𝐘𝐨𝐮 𝐜𝐚𝐧 𝐞𝐱𝐩𝐞𝐜𝐭: ✔ Clean, maintainable code ✔ Architecture-first development ✔ Transparent communication ✔ Production-ready software ✔ Thorough documentation ✔ Long-term technical partnership If you're looking for an experienced engineer who can build complex software, integrate AI, and scale products from MVP to enterprise, I'd love to discuss your project.

I build mobile apps, websites, SaaS platforms, and AI-based products. I handle both UI/UX design and full-stack development, so you can work with one reliable partner from initial planning and Figma design to development, testing, deployment, and launch. My services include: AI-powered mobile app development SaaS product design and development WordPress website design and development Shopify store design and development Website and landing page design UI/UX design in Figma Flutter app development React Native app development Android apps using Java and Kotlin iOS apps using Swift and SwiftUI React, Next.js, and Node.js development Supabase, Firebase, and PostgreSQL setup AI and LLM integrations using OpenAI, Claude, Gemini, and similar tools API integrations, payments, and subscriptions App Store, Play Store, and web deployment I keep the product simple, fast, and easy to use. I do not add unnecessary features or make the system more complicated than it needs to be. You can expect clear communication, regular updates, clean work, and practical suggestions throughout the project. From the first design to the final launch, I can handle the complete product development process.

I help startups and businesses turn ideas into high-quality, scalable mobile apps that users love and that actually perform in the real world. With 6+ years of experience as a Senior Mobile App Developer, I specialize in building production-ready iOS and Android apps using Flutter, delivering native-level performance with faster development and lower cost. I don’t just write code — I take full ownership of your app from idea to App Store launch. 🚀 What I Can Do for You 📱 Mobile App Development (iOS & Android) Flutter (single codebase, native performance) Clean, scalable, and maintainable architecture MVPs, full products, and existing app improvements ☁️ Backend & Cloud Integration Firebase (Auth, Firestore, Cloud Functions) REST APIs & custom backends Secure, scalable data handling 💳 Payments & Third-Party Integrations Stripe, PayPal, In-App Purchases Google Maps, Social Login (Google, Apple, Facebook) Analytics & performance monitoring 🎨 UI/UX Implementation Pixel-perfect UI from Figma / Adobe XD Smooth animations and intuitive user experience ⚡ Performance & Quality Fast load times and smooth animations Bug fixing, optimization, and best practices Apps ready for App Store & Google Play approval ⭐ Why Clients Choose Me ✅ End-to-End Ownership – From concept to deployment and post-launch support ✅ Get It Right the First Time – Fewer bugs, faster delivery, better results ✅ Clear Communication – Regular updates, honest timelines, no surprises ✅ Proven Delivery – Multiple live apps on App Store & Google Play 🤝 Let’s Build Your App If you’re looking for a reliable, experienced Flutter developer who understands both technology and business goals, let’s talk. Send me a message and tell me: What problem does your app solves Your timeline Your target users I’ll help you turn it into a successful mobile product.

I lead a dev team that specializes in building mobile apps. Over the last 10 years, we’ve successfully delivered over 180+ projects, including more than 30 top-rated apps right here on Upwork. Whether you need a Flutter developer or a React Native specialist to build a high-performance app for both platforms fast and efficiently, we have you covered. Our sweet spot is crafting smooth mobile experiences, but we also bring strong Web developer and Full Stack developer expertise to the table, allowing us to build everything from quick MVPs to full-scale production platforms with complex backends. Whether you are working with connected hardware (IoT), health-tech, or heavy data workflows, we handle everything from the initial design to post-launch scaling. Let’s connect for a quick chat to discuss your project and see how we can help bring it to life!

Hello , If you are looking for a developer who can turn your app idea into a fast, scalable, and production-ready product, you are in the right place. I’m a senior mobile app developer with 8+ years of experience building high-performance, scalable, and user-focused mobile applications for startups, growing businesses, and enterprise clients. I specialize in Flutter and React Native to develop cross-platform apps that deliver native-level performance on both iOS and Android while reducing development time and cost. Beyond mobile development, I also help businesses integrate AI-powered features and automation into their apps including intelligent chat systems, AI workflows, smart recommendations, automation engines, and API-driven business logic that improve user engagement and operational efficiency. Core Expertise ✅ Flutter & React Native Cross-Platform Development ✅ AI Integration (Chatbots, OpenAI APIs, Smart Automation) ✅ MVP Development for Startups ✅ Scalable Mobile App Architecture ✅ Firebase, Supabase, REST APIs, GraphQL ✅ Payment Gateway Integration (Stripe, Razorpay, PayPal) ✅ Push Notifications, Maps, Chat, Social Login ✅ App Store & Play Store Deployment ✅ Performance Optimization & Long-Term Support Modern Tech Stack Frontend: Flutter, React Native, Dart, JavaScript, TypeScript Backend: Firebase, Node.js, Supabase AI & Automation: OpenAI APIs, Workflow Automation, AI-powered App Features Tools: Git, CI/CD, Figma, Jira, Trello What I Build 📱 E-commerce Apps 📱 Booking Platforms 📱 SaaS Mobile Products 📱 EdTech Apps 📱 CRM Mobile Solutions 📱 On-Demand Service Apps 📱 AI-enabled Mobile Applications Recent Project Experience - Built scalable e-commerce app supporting 50K+ active users - Developed booking platform with live GPS tracking and payments - Created EdTech mobile platform with video streaming and assessments - Integrated AI-driven automation into business workflows I focus on writing clean code, maintaining clear communication, and delivering products that are technically strong and commercially successful. If you need a developer who understands both mobile engineering and modern AI product trends, let’s connect. Send a message and let’s discuss your project.

I’m a Full-Stack Developer with experience building SaaS platforms, AI-powered applications, ERP systems, healthcare products, and custom web applications using React, Next.js, Node.js, and TypeScript. Most of my work involves helping startups and businesses: - build a product from scratch, - improve an existing platform, -or solve scaling/performance issues as the product grows. I’m comfortable handling both frontend and backend development, from building responsive user interfaces to designing APIs, database architecture, cloud infrastructure, and third-party integrations. A few types of projects I’ve worked on include: >> SaaS platforms with multi-user workflows >> AI-based features and automation tools >> Healthcare and compliance-focused applications >> Real-time communication platforms >> ERP and business management systems >> Custom dashboards and admin panels Tech stack I work with regularly - React.js, Next.js, Node.js, TypeScript, PostgreSQL, MongoDB, AWS, Docker, REST APIs, GraphQL, and OpenAI integrations. I care a lot about writing clean and maintainable code, keeping communication clear during the project, and building systems that are stable long-term not just quick fixes. If you need help building or improving a SaaS product, web application, or AI-powered platform, feel free to send me a message or invite me to your project.

OVERVIEW I build AI-powered full-stack products that go to market not just get started. From LLM applications and RAG systems to SaaS platforms and mobile apps, I work as a Full-Stack AI Engineer who can own a project end to end, from architecture to deployment. If you need an AI engineer who combines deep LLM expertise with full-stack and mobile development Let's talk. My Upwork credentials: Top Rated Plus Freelancer 97% Job Success Score 90% client recommendation rate 86% repeat client rate most clients come back for a second project 100+ successful projects for startups and enterprises 9500+ hours in full-stack, AI, and mobile development 14+ years in software engineering I specialize in building AI-powered systems using LLMs, AI Agents, RAG pipelines, and LangChain combined with full-stack web development in React and Next.js, scalable backend systems in Python, Node.js, and FastAPI, and cross-platform mobile apps in React Native. My approach focuses on building production ready systems, not just prototypes clean architecture, modular design, and scalable infrastructure that your team can maintain and grow. SERVICES I PROVIDE AI & LLM Engineering LLM Applications & AI Integrations (OpenAI, Hugging Face) RAG Systems for private data and enterprise search AI Agents & Automation Workflows with LangChain and LangGraph Backend APIs with FastAPI, Node.js, or Django REST Data pipelines and AI processing systems Vector databases Pinecone, ChromaDB Cloud deployment & scalable architecture (AWS / GCP / Azure) Full-Stack Web Development Modern web apps using React and Next.js Scalable backend systems with Node.js and Laravel SaaS platform development and startup MVP builds RESTful & GraphQL API development Database design and optimization PostgreSQL, MongoDB Admin dashboards and enterprise systems Mobile App Development Cross-platform mobile apps using React Native Native iOS development with Swift and SwiftUI Native Android development with Kotlin and Jetpack Scalable mobile architecture for startups and SaaS products Performance-optimized, secure, production-ready mobile apps WHY CLIENTS HIRE ME ✔ 86% of clients return for a second project I deliver what I scope, on time, every time ✔ I combine AI/LLM engineering with full-stack and mobile one developer, complete product ✔ I build production-ready systems, not prototypes clean, modular, maintainable code ✔ I communicate proactively you'll always know where your project stands ✔ 14+ years of engineering experience across startups, SaaS, and enterprise products TECHNOLOGY STACK AI & LLM: LangChain · LangGraph · OpenAI API · Hugging Face · RAG · AI Agents · Whisper · TTS Frontend: React.js · Next.js · TypeScript · JavaScript · Tailwind CSS Backend: Python · Node.js · FastAPI · Django · Laravel · PHP Mobile: React Native · Swift / SwiftUI · Kotlin / Jetpack Databases: PostgreSQL · MongoDB · ChromaDB · Pinecone · Firebase Cloud & DevOps: AWS · GCP · Azure · Docker · CI/CD INDUSTRIES SERVED · SaaS Platforms · Fintech & Payments · Healthcare & AI · EdTech · E-Commerce · Logistics · On-Demand Services CLOSING Whether you need an AI Engineer to build LLM-powered SaaS, a RAG system for your private data, or a full-stack developer to ship your MVP, I'd love to hear about your project. Send me a message and let's see if we're a good fit.