Top Rated Web Developer in the top 1% of talent in development — 100% JSS, $190K+ earned, 4,500+ hours delivered. 10+ years building websites, web applications and high-load platforms as a Node.js Developer and React Developer — from startup MVPs and custom web design to systems serving 15M+ users. I pair full-cycle Web Development with Full Stack AI: LLM integrations, AI agents and RAG pipelines built into real products. I own the full stack as one engineer. Hire me as a Web Developer for website developer builds, website redesign, web application development and ecommerce website development; as a Node.js Developer for backend developer work, API development and node.js backend developer services; as a React Developer for react web developer projects, web app developer react builds and react native developer front ends; or for Full Stack AI — AI agent development, AI app development and full stack developer ai agents wired straight into your product. What I build: 🧩 Front-End Development — responsive, production-ready interfaces for SaaS and ecommerce marketplaces: React Next.js JavaScript TypeScript HTML CSS Redux TanStack Query MUI Shadcn Tailwind CSS Bootstrap Vue.js web design website customization Web Component Design ⚙️ Back-End Development — APIs, microservices, event-driven architecture, high-load systems and horizontal scaling: Node.js ExpressJS NestJS NestJS Development NodeJS Framework REST GraphQL WebSocket gRPC RabbitMQ API Development 🗄️ Database Development — clean schema design for multi-tenant SaaS and high-throughput pipelines: PostgreSQL MongoDB MySQL Redis Prisma TypeORM Mongoose Firebase ☁️ Cloud and DevOps — scalable infrastructure, monitoring and zero-downtime releases: AWS Docker Kubernetes Nginx Prometheus Grafana Git CI/CD Web Hosting 🤖 Full Stack AI — AI-powered products since the earliest LLM APIs: LLM Integration Claude and OpenAI APIs AI agents RAG pipelines vector search NLP prompt engineering MCP Agentic Engineering AI Development AI workflow automation 🔗 Web3 — secure financial flows and blockchain analytics: web3.js Solidity smart contracts DeFi EVM Solana TON HD wallets Industries: FinTech, SaaS, CRM, ecommerce, marketplace, B2B platforms and healthcare. Services I deliver: Web Development Website Redesign Custom Web Design Ecommerce Website Development SaaS Development API Development AI Agent Development Performance Optimization Beyond the core build I handle admin dashboards, real-time applications, performance audits and legacy modernization. I step in as a WordPress Development, Shopify Development and CMS Development partner — wordpress developer work included — for content-heavy and commerce sites, and as a Website Builder or Website Customization specialist handling back end web developer and back end developer node.js work on existing codebases. For mobile I deliver App Development and Mobile App Development with React Native — iOS Development, iPad App Development and Android App Development from one codebase. I also adapt to whatever stack a project already runs on: ai web developer wiring AI Development into web apps react developer firebase full stack developer react firebase full stack developer supabase react react django developer python developer front end developer html web developer javascript developer CRM Development, web developer ecommerce flows, QA and observability are part of delivery. Selected results: ⭐ Scaled a SocialFi platform from 500K to 15M+ users as a Node.js Developer and architect — 1,500%+ faster response times. ⭐ Launched a SaaS product as a full stack Web Developer in 10 days; scaled to 1M+ leads/year at 99.9% uptime. ⭐ Built a real-time blockchain analytics platform as a React Developer; wallet aggregation from ~10 minutes to 5–40 seconds. ⭐ Delivered a marketplace aggregator processing 1M+ items in near real time with anti-fraud and double-entry financial controls. Core stack: Node.js TypeScript React Next.js NestJS ExpressJS PostgreSQL MongoDB MySQL Redis RabbitMQ AWS Docker web3.js Vue.js How I work: I treat Web Development as one accountable role spanning Software Architecture & Design, Software Development and Full-Stack Development, through deployment and post-launch Performance Optimization. Comfortable as the solo engineer on a startup MVP or website, or the tech lead mentoring a team across product, design and business stakeholders. Predictable delivery, clear communication, commercial outcomes. Ready to build or scale your website, web application or AI-powered product? If your project needs a Web Developer, Node.js Developer, React Developer or Full Stack AI engineer — let's talk.

Let’s turn complex ideas into powerful systems — fast, scalable, and future-ready. Oleksandr will do 🎯 𝐌𝐲 𝐂𝐨𝐫𝐞 𝐄𝐱𝐩𝐞𝐫𝐭𝐢𝐬𝐞 ✅ 𝐀𝐈 𝐀𝐠𝐞𝐧𝐭𝐬 & 𝐒𝐦𝐚𝐫𝐭 𝐀𝐮𝐭𝐨𝐦𝐚𝐭𝐢𝐨𝐧 ‣ LLM-Driven Agents (LangChain, AutoGPT, RAG, Function Calling) ‣ Context-Aware Bots (Voice, Vision, Embeddings, Multi-Modal) ‣ Autonomous Workflows (Zapier, N8N, Make.com, custom DAGs) ✅ 𝐖𝐞𝐛3 & 𝐁𝐥𝐨𝐜𝐤𝐜𝐡𝐚𝐢𝐧 𝐒𝐲𝐬𝐭𝐞𝐦𝐬 ‣ Sniper & Arbitrage Bots (Solana, ETH, BSC, Base) ‣ Smart Contract Dev (Solidity, Foundry, Hardhat) ‣ MEV, DEX/CEX Integration, Wallet Automation ✅ 𝐃𝐚𝐭𝐚 𝐄𝐱𝐭𝐫𝐚𝐜𝐭𝐢𝐨𝐧 & 𝐃𝐲𝐧𝐚𝐦𝐢𝐜 𝐏𝐚𝐫𝐬𝐢𝐧𝐠 ‣ Advanced Web Scraping (Selenium, Playwright, Puppeteer) ‣ DOM + Shadow DOM + Canvas Scraping Solutions ‣ Realtime Monitoring, CAPTCHA Bypass, Stealth Automation ✅ 𝐅𝐮𝐥𝐥-𝐒𝐭𝐚𝐜𝐤 𝐄𝐧𝐠𝐢𝐧𝐞𝐞𝐫𝐢𝐧𝐠 ‣ Frontend: React, Next.js, Tailwind, Vue ‣ Backend: Node.js, Python, FastAPI, Express ‣ Databases: PostgreSQL (with pgvector), MongoDB, Redis ‣ DevOps: Docker, CI/CD, AWS, GCP, Vercel, Firebase 💡 𝐖𝐡𝐲 𝐂𝐥𝐢𝐞𝐧𝐭𝐬 𝐂𝐡𝐨𝐨𝐬𝐞 𝐌𝐞 ✅ End-to-End Builder — From idea to production ✅ Deep Technical Rigor — Clean, scalable, testable systems ✅ Results-Oriented — I solve real business problems, not just code ✅ Up-to-Date — I bring the latest in AI, automation & crypto tech 📬 Whether you need an AI agent that talks, a bot that snipes, or a full-stack platform that scales — I deliver. 📈 Let’s launch high-impact projects, together.- Message me at any time

Are you looking for a reliable and highly skilled Full-Stack Developer who can deliver robust, scalable, and secure applications from concept to production? You've found the right professional. With 6+ years of hands-on experience working with leading multinational companies, I specialize in building enterprise-grade web applications using cutting-edge technologies. From designing system architecture to coding back-end microservices and crafting seamless front-end interfaces, I deliver end-to-end solutions tailored to your business goals. ✅ Tech Stack Expertise: Backend: Java, Spring Boot, Spring MVC, Spring Cloud, Hibernate, JPA Frontend: React.js, HTML5, CSS3, JavaScript Databases: MySQL, PostgreSQL, Oracle Architecture: Monolithic & Microservices Dev Tools: Kafka, RabbitMQ, Zipkin, ELK Stack, Circuit Breaker API Development: RESTful APIs, Authentication, Security, Scalability Blockchain & Web3: Crypto coins & token development Wallet integration Payment gateways Uniswap integration NFT minting Cross-chain bridges (e.g., BSC) 🏆 What I Offer: Detailed project plans with feasibility analysis and clear scope Clean, maintainable code with documentation Agile development & timely delivery Scalability and performance-focused solutions Long-term support and maintenance I've also led and managed large enterprise projects involving complex systems and cross-functional teams. Whether you're a startup building your MVP or an enterprise optimizing your systems, I bring deep technical insight and a solution-oriented approach to every project. Let's connect to discuss how I can bring your idea to life with precision and reliability

Upwork Expert-Vetted Talent (Top 1%) Microsoft Certified AI Engineer (Certification number: DEB32A-P5EE8C) Fullstack Developer | Software Engineer | Solutions Architect | AI Engineer | UI/UX Designer Tech Stacks Languages & Frameworks: C / C++ / C# / .NET / Unity / Java / JavaScript / TypeScript / Python / Rust / PHP / VB Razor Pages / CSS3 / Maven / Spring / Angular 2+ / React.js / Redux / jQuery / HTML5 / JSX / XAML / XML/XSLT / ASP.NET MVC / ASP.NET Core / .NET Framework / DevExpress UI / Spring Framework / Spring Boot / Spring Cloud / JavaFX / QT / QML Databases: MySQL / PostgreSQL / MSSQL / NoSQL / MongoDB / Azure Cosmos DB / Redis / Firebase Realtime Database DevOps & Containerization: Docker / Kubernetes / Azure DevOps AI & Machine Learning: Machine Learning / Deep Learning / TensorFlow / PyTorch / MATLAB / Azure Cognitive Services / Azure OpenAI Services / Azure AI Video Indexer / Azure AI Prompt Flow / Google Assistant SDK Blockchain Development: Ethereum / Binance Smart Chain / Solana / Stellar / Smart Contract Development / IoT Blockchain Technologies Additional Tools & Platforms: QuickBooks Online (Intuit) App Development / Shopify App Development Full Stack Development Services App Development: Mobile, Web, and Desktop Applications, Macros & Scripts Blockchain Development: Smart Contract Development and Blockchain Integration for Ethereum, Binance Smart Chain, Solana, and Stellar Algorithmic Trading: Algo Trading Platforms for Stocks and Cryptocurrency Dashboards & Analytics: Custom Dashboards, Metrics, and Business Intelligence Solutions Custom CRM & ERP Systems: Design, Development, and Integration of Customized CRM and ERP Solutions Database Management: Database Design, Optimization, Maintenance, and Integration for MySQL, PostgreSQL, MSSQL, NoSQL, MongoDB, and other leading database systems Software Integrations: Third-Party Software Integration and IT Security Implementations AI & Cognitive Services: Development of Machine Learning, Deep Learning, and Cognitive AI Solutions using Azure AI Stacks (Cognitive Services, OpenAI, Prompt Flow, Video Indexer) and Google AI SDK

AI developer and full-stack engineer with 16+ years building production software for US clients. I integrate LLMs (GPT, Claude), RAG pipelines, and AI chatbots into real, shippable products — not demos. Most "AI experts" can only call an API. I build the entire product around the AI: the app, the backend, the database, and the deployment. That's why clients keep me from first commit through post-launch. What I build: → AI Integration — LLM apps (GPT, Claude, OpenAI API), RAG pipelines, AI chatbots, NLP, computer vision, AI agents → Full-Stack / MERN — SaaS platforms, dashboards, and AI-powered web apps (React, Next.js, Node.js, Express, MongoDB) → React Native — cross-platform iOS & Android apps, including AI features on mobile → Also available: Unity 3D games & AR/VR when a project needs it Recent work: • AI chatbot trained on a client's knowledge base using RAG • API-first SaaS infrastructure platform (React) • Full booking + management platform — web + mobile (MERN + React Native) • Food delivery app serving thousands of daily users (React Native + Node.js) • 15+ published games on App Store and Google Play What you get working with me: ✓ AI that actually ships — integrated, tested, production-ready, not a proof-of-concept ✓ One developer for frontend, backend, database, deployment — and the AI layer ✓ Senior-level, clean, documented code ✓ 4–6 hours daily overlap with US Eastern/Central ✓ Fast communication — Slack, Zoom, whatever you prefer ✓ NDA signed before work begins — your IP is yours ✓ Hourly or fixed-price Tech: OpenAI API · GPT · Claude · RAG · NLP · Python · TensorFlow · React · Next.js · Node.js · Express · MongoDB · TypeScript · React Native · AWS · Docker · PostgreSQL · Redis · Firebase · Unity 3D · C#

Hello! I'm Jonathan, a seasoned Full-Stack and blockchain engineer with a strong passion for crafting innovative and scalable digital solutions. With more than 5 years of hands-on experience, I've collaborated with a diverse range of clients and organizations to bring their ideas to life through high-quality, robust products. Skills🧰 🧑🏾‍💻 Programming Languages: JavaScript, TypeScript, Golang, Rust 🤖 Frontend: JavaScript, TypeScript, React.js, Next.js, React Native, Tailwind, Web3JS, Wagmi 🤖 Backend: Express.js, Nest.js , Redis, GORM, GIN, MUX. ⛓️ Blockchain: Solana, Ethereum, Cosmos 📖 Databases: PostgreSQL, Redis, MongoDB, IPFS. 🛠 Tools: AWS, Docker, Microservices, CI/CD, Kubernetes, GraphQL, Kafka, Sentry ⚙️Development skills: Blockchain Development, System design, Distributed systems, Cryptography, AI. 𝗪𝗵𝘆 𝗰𝗵𝗼𝗼𝘀𝗲 𝗺𝗲?🤔 ✔ Collaborative Team Player: I have extensive experience working within diverse teams, ensuring seamless integration and collaboration. ✔ Reliable & Accountable: I pride myself on delivering what I promise, maintaining transparency and reliability throughout every project. ✔ Efficient & Timely: Deadlines are non-negotiable. I work efficiently to deliver quality work within the required timeframe. Whether you're looking for a reliable developer for long-term collaboration or someone to tackle a short-term project with precision and speed, I'm here to help bring your vision to reality. Let's connect and discuss how we can make your project a success. Best regards, Jonathan.

Hey there! I’m a senior engineer building AI-powered applications — LLM apps, autonomous agents, and RAG systems — backed by 5+ years shipping production software and a 100% Job Success score across 36 projects ($40K+ earned). What I build with AI: • LLM-powered apps using the OpenAI and Anthropic (Claude) APIs — chatbots, copilots, content and automation tools • RAG systems (retrieval-augmented generation) — chat over your documents, knowledge bases, and internal data using vector databases like Pinecone and Chroma • AI agents and workflow automation — tool-calling agents that research, summarize, and execute multi-step tasks • API integration and scalable backends to run it all in production (Node.js, TypeScript, Python) My edge: I come from a deep backend and Web3 background (Solidity, Rust, DEXs, trading bots, real-time systems), so I’m one of the few engineers who can build at the intersection of AI and blockchain — on-chain AI agents, AI-assisted smart-contract auditing, and trading automation with LLM decision layers. Whether you need an LLM app, an AI agent, a RAG pipeline, or a scalable backend to power them, I’ll help bring your idea to production. Let’s talk.

Blockchain & NFT Developer | Agentic AI & Workflow Specialist Hello! I’m an experienced Blockchain Developer and Smart Contract Auditor with deep expertise in building secure DeFi and NFT projects. I also specialize in Agentic AI and intelligent workflow automation. Blockchain & DeFi Expertise: Proficient with top protocols: Uniswap (V2/V3/V4 swaps, liquidity pools, hooks), Aave (lending, borrowing, flash loans), Compound, and Curve Develop secure, gas-efficient, upgradable Solidity smart contracts (ERC-20, ERC-721, ERC-1155) Build DEXs, lending platforms, yield farms, and NFT marketplaces Conduct thorough smart contract audits and security reviews Gas optimization, bug fixing, Hardhat/Foundry testing, and frontend integration (React + Web3.js/ethers.js) Agentic AI & Workflow Expertise: Design and develop autonomous AI agents for on-chain automation, market monitoring, yield optimization, and strategy execution Build intelligent workflows that enable smart contracts to interact dynamically with AI-driven decision making Create AI-powered systems for risk management, portfolio rebalancing, and automated DeFi operations I focus on delivering secure, efficient, maintainable, and mainnet-ready solutions. Whether you need robust blockchain infrastructure or powerful agentic AI workflows, I help you avoid hacks and build systems that scale intelligently. If you’re looking for a trusted expert in both Blockchain/NFT development and Agentic AI automation, let’s discuss your project.

Helping startups turn ideas into scalable AI products, SaaS platforms, and automation systems. As a Full Stack AI Engineer with 10+ years of software development experience, I specialize in building AI-powered applications, autonomous AI agents, production-grade RAG systems, and robust SaaS architectures. I combine deep product thinking, modern system architecture, and hands-on full-stack development to deliver secure, scalable, and production-ready software that drives real business value. What I Can Build For You as Your Full Stack AI Engineer: - AI-Powered SaaS Applications - AI Agents & Business Automation - RAG (Retrieval-Augmented Generation) Systems - Custom Full Stack Web Applications - SaaS Platforms & Multi-Tenant Architectures - API Development & Third-Party Integrations - Legacy System Modernization - System Design & Technical Architecture - Multi-Agent Workflows - ComfyUI Custom Workflows DOMAIN SPECIALTIES & BUSINESS IMPACT Full-Stack AI & SaaS Core Infrastructure: I build the entire multi-tenant SaaS ecosystem around your AI—handling frontend UX, secure token management, and robust backend infrastructure so it scales smoothly. Autonomous Agents & Full Stack AI Logic: I deploy multi-agent orchestrations (LangGraph, LangChain, CrewAI) that plug directly into your SaaS backend to automate complex business logic, background processing, and intelligent decision-making. Production-Grade RAG & Data Architecture: I engineer highly accurate Retrieval-Augmented Generation systems, setting up secure metadata filtering and optimized vector databases (Pinecone, Qdrant, pgvector) that sync perfectly with your application’s data layer. Low-Latency Voice & Full-Stack Streaming: I implement the WebSockets and state management required for sub-500ms real-time voice assistants (Deepgram, ElevenLabs, OpenAI Whisper), ensuring live streaming works flawlessly. Custom E-Signature Platforms & Document Workflows: I architect secure, compliant digital signature systems from the ground up. This combines frontend canvas-based signing with heavy backend engineering, including secure document hashing, immutable audit trails, and complex, multi-party signing state machines (parallel, sequential, and conditional signing logic). Technical Stack Matrix AI & Agentic Frameworks: OpenAI, Claude, Gemini, LangGraph, LangChain, CrewAI, AutoGen, Vector DBs (Pinecone, Qdrant, pgvector) Frontend Development: React.js, Next.js, Vue.js, TypeScript, Tailwind CSS Backend Engineering: Node.js, .NET Core, ASP.NET Core, Python, FastAPI, Django, Laravel Cloud & Infrastructure: AWS, Docker, PostgreSQL, MySQL, Redis, Supabase Workflows & Automation: ComfyUI, n8n, Zapier, Make, LangFlow Integrations: Stripe, Twilio, Google Workspace, Slack, Zoom, Meta APIs, and custom enterprise REST/GraphQL APIs Why Clients Partner With Me: • 10+ years of hands-on engineering experience across frontend, backend, and AI layers. • 70+ projects successfully delivered from initial concept to live production. • Strong system design background ensuring your software is built right the first time. • Fast execution without compromising on security, readability, or code quality. • Ownership mindset—I act as a technical partner, not just a task-taker. ⏱ Availability & Engagement: Hours: 40–50 hours/week | Full-time availability Focus: Long-term enterprise contracts, complex SaaS architecture, full-stack AI integrations, and ongoing product development partnerships. 𝑰𝒇 𝒚𝒐𝒖 𝒏𝒆𝒆𝒅 𝒂 𝑭𝒖𝒍𝒍 𝑺𝒕𝒂𝒄𝒌 𝑨𝑰 𝑬𝒏𝒈𝒊𝒏𝒆𝒆𝒓 𝒘𝒉𝒐 𝒄𝒂𝒏 𝒅𝒆𝒔𝒊𝒈𝒏, 𝒃𝒖𝒊𝒍𝒅, 𝒂𝒏𝒅 𝒔𝒄𝒂𝒍𝒆 𝒚𝒐𝒖𝒓 𝒑𝒓𝒐𝒅𝒖𝒄𝒕 𝒇𝒓𝒐𝒎 𝒄𝒐𝒏𝒄𝒆𝒑𝒕 𝒕𝒐 𝒑𝒓𝒐𝒅𝒖𝒄𝒕𝒊𝒐𝒏, 𝒍𝒆𝒕’𝒔 𝒄𝒐𝒏𝒏𝒆𝒄𝒕.

Any sufficiently advanced technology is indistinguishable from magic. I build technology that feels like magic - but runs on solid engineering. I am an Intelligent Systems Architect focused on designing and delivering advanced software systems that combine AI, scalable infrastructure, and modern applications. I don’t just write code - I design complete, production-ready systems that are reliable, efficient, and built to grow. My core strengths include: - AI & Machine Learning systems (LLMs, neural networks, automation) - Scalable backend and distributed architectures - Web and application development - Blockchain-integrated platforms - IoT-connected systems - Advanced algorithms and performance optimization I specialize in turning complex ideas into clean, maintainable, and high-performance solutions. Whether it’s building an AI-powered SaaS product, a decentralized application, or a data-driven platform, I focus on clarity, scalability, and long-term impact. If you’re building something ambitious and need a technical partner who understands systems end-to-end, I’m ready to help make it real.