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🟢 Available for ongoing hourly work I help teams build, maintain and modernize React, Next.js and Node.js applications - especially SaaS products, CMS-driven platforms, dashboards and business-critical web apps. I work best with existing products where the team needs a reliable full-stack developer who can understand the codebase, investigate issues, fix bugs, improve performance, connect frontend with backend systems and keep shipping without unnecessary hand-holding. What I can help with: → React / Next.js development, bug fixing and refactoring → Node.js APIs, integrations and backend logic → SaaS dashboards, admin panels and business-critical web apps → Payload CMS, Statamic and headless CMS setup or cleanup → Website speed, Lighthouse and Core Web Vitals optimization → Forms, lead tracking, CRM / Google Sheets integrations and automation → Angular legacy upgrades when needed → Technical audits with a clear roadmap before implementation Why clients work with me: • 10+ years of full-stack development experience • $100K+ earned on Upwork • 100% Job Success • Top Rated Plus - top 3% of talent on Upwork • Strong experience with long-term projects, legacy systems and existing codebases • I work async, communicate clearly and can take tasks from investigation to implementation • Comfortable working with US, UK, EU and CEE clients Recent work: ▪ Upgraded a large legacy Angular application to a modern version ▪ Built a real estate platform with Payload CMS + Next.js and custom editorial workflows ▪ Built Next.js + Statamic CMS websites for business and healthcare clients ▪ Improved website performance, forms, tracking and lead flow for existing websites ▪ Built and launched React Native apps for iOS and Android A good first step is usually a small technical audit, fixed-scope rescue sprint or first implementation milestone. I can identify the highest-impact issues, explain what is worth fixing first, and then continue with implementation or ongoing hourly support.

Hello! I'm a versatile Full-Stack and AI Developer with 8+ years of experience building scalable, high-performance web applications and intelligent digital solutions. I specialize in both front-end and back-end development, combining modern JavaScript frameworks with Python, cloud infrastructure, and AI technologies to deliver full-fledged products. My tech toolkit includes React.js, Vue.js, Angular, Node.js, Python, FastAPI, MongoDB, PostgreSQL, and a strong command of AWS services, including Lambda, Cognito, Amplify, Generative AI, LLM, Tensorflow, Langchain and more. I’ve also worked on GPT-powered features, integrating AI models to create smarter, more responsive applications. ✅ Services Offered: Front-End Development Responsive, user-centric UI design with React, Vue, and Angular State management using Redux, Vuex, etc. Seamless API integrations (REST & GraphQL) Performance optimization and accessibility best practices Back-End Development Robust API and microservice development using Node.js, Express, and FastAPI Python-based back-end logic for data processing, automation, and API services Secure authentication/authorization systems and custom middleware Database design and optimization (MongoDB, PostgreSQL) Web scraping (scraped sites like EBay for product information with images) AI & GPT Integrations Custom GPT-3.5/GPT-4 integrations for automation, chatbots, and smart UI features Prompt engineering and fine-tuned AI workflows Back-end support for AI features, including caching and input sanitization Data pipelines (from scratch and using individual components, not by using services like databricks or airflow) Machine learning models, their tuning and data analytics (using libraries like Tensorflow, langchain, crewAI, PowerBI) Cloud Services & DevOps AWS Cognito for secure user authentication and identity management AWS Lambda for serverless backend logic and API endpoints AWS Amplify for fast, scalable full-stack deployment and hosting Containerization with Docker and orchestration using Kubernetes CI/CD pipelines for efficient development and delivery Full-Stack Solutions Full end-to-end development with MERN, MEVN, or Python + React stacks Third-party API integrations and real-time features (WebSockets, Pub/Sub) Scalable infrastructure on AWS, including EC2, S3, CloudFront, and RDS 💼 Why Work With Me? Client-Focused: I align my work with your business needs and project goals Results-Oriented: Clean, maintainable, high-performance code every time Reliable Communication: Regular updates, collaborative approach, and full transparency On-Time Delivery: I respect deadlines and take ownership of getting the job done right Let’s turn your ideas into reality. Whether you're building an MVP, enhancing an existing system, or integrating AI-driven features, I’m here to help. Let’s connect and talk about how I can bring value to your next project!

Back-end Developer/Engineer | AI, RAG, LLM, Real Estate, Sports, Retail, CRM | Scalable Systems | Python, Node.js | Front-end Developer | React.js, Next.js | AWS | GCP ✔ 8+ years of experience building scalable backend systems and AI-powered applications ✔ Specialized in Python, LLM integration, and production-ready AI deployment ✔ Focused on delivering real-world AI products that are reliable, maintainable, and scalable I help startups and businesses design, build, and deploy production-ready AI applications and backend systems. Whether you need: ➡️ An MVP for your AI SaaS product ➡️ LLM-powered applications using the OpenAI API, Anthropic, or Google ➡️ Retrieval-Augmented Generation (RAG) pipelines ➡️ Sports analytics and AI-powered sports applications ➡️ AI solutions for sports, fitness, and performance tracking ➡️ Sports data pipelines, analytics, and prediction systems ➡️ AI agents and workflow automation ➡️ Machine learning models deployed as APIs ➡️ Scalable Python backend services I can take your project from concept to production. My focus is on building robust systems that turn AI capabilities into practical, user-facing products. What I Build ➡️ AI/ML backend systems in Python ➡️ LLM applications (RAG, chatbots, AI agents) ➡️ Model deployment and inference APIs ➡️ Data pipelines and ETL systems ➡️ AI SaaS products and MVPs ➡️ Workflow automation and third-party integrations ➡️ Development Approach ➡️ Production-first AI development ➡️ Clean, maintainable architecture ➡️ Fast MVP delivery ➡️ Scalable API design ➡️ Clear communication and proactive ownership Skills & Technologies ➡️ Backend & APIs ➡️ Python ➡️ FastAPI ➡️ Django ➡️ Node.js ➡️ Express.js ➡️ Nest.js ➡️ REST APIs ➡️ System Design ➡️ AI / Machine Learning ➡️ Machine Learning ➡️ LLMs ➡️ RAG ➡️ AI Agents ➡️ NLP ➡️ OpenAI ➡️ Anthropic ➡️ Google ➡️ Hugging Face ➡️ Infrastructure ➡️ Docker ➡️ Cloud Deployment ➡️ Model Serving ➡️ Data Pipelines ➡️ Databases ➡️ PostgreSQL ➡️ Supabase ➡️ Firebase ➡️ Automation & Integrations ➡️ API Integrations ➡️ Workflow Automation ➡️ What You Can Expect ➡️ Clean, maintainable Python code ➡️ Production-ready AI systems ➡️ Scalable backend architecture ➡️ Fast turnaround for MVPs ➡️ Clear communication throughout the project Let’s Build Your AI Product If you're building an AI application, LLM-powered SaaS, or scalable Python and Node.js backend, I’d be happy to help turn your idea into a production-ready product. Send me a message and let’s discuss your project.

Do you need IT help for your business but find working with developers difficult? Are you struggling to achieve your business goals with the software you use? I'm here to take this burden off your shoulders so that you can focus on what you do best - your business. Programming, for me, is a tool only - not an objective itself. I will take care of all IT work and make sure it is aligned with your goals. Here are the ways I help companies thrive: • Building XML related systems — many times XML is the best choice for exchanging data, especially when you need to control the structure of nested nodes of data. I'll help you utilize the best of XML technology so it can effectively serve your business needs. • Design of tailored systems — when your business model that needs a boost with an automated, intelligent software. I'll work with you closely to understand the goals and build software that moves your productivity and profits to a completely new level. • Optimization of existing systems — when your software doesn't fully serve your needs. I'll transform it in the most effective way to keep all that is good in it and add the new value you are seeking. • Building a team - when you need to effectively achieve your IT goals. I'll find the best people that can achieve your goals within the budget and time. • Building a website - when you want to improve your online presence. I'll design a beautiful and fast website that brings you more clients and conversions. You will see a major increase in your productivity and profitability, your systems will start bringing you clients and money. With me, you get someone who understands your business and speaks your language - an honest professional whom you can trust. What clients say about my work: "Single handedly the best developer I have ever come across in my 15 years working in this industry. I cannot recommend Jacek enough. His professionalism, quality of work, delivery, communication are all of the highest quality. I will be putting more work Jacek's way." - Richard "I've already scheduled another project with Jacek. It's always a pleasure!" - Cheryl "Designed the page within my guidelines and requirements. Made front end elegant and functional. Back end was clean and user-friendly. Fantastic communication, extensive expertise. Will hire in future" - Vitold Technologies I work with: * XSLT, XPath, XML, XML Schema, exist-db, Apache FOP, Ibex, Xalan, MSXSL, Saxon, Dita, Docbook, EXSLT, XQuery, xsltproc, HTML5, XHTML, SVG, SpreadsheetML, WordProcessingML, lxml * GIS Systems: Google Maps, OpenStreet Maps, Gisgraphy, Geocoding, Leflet, Mapbox, FusionTables, OpenLayers, Geonames * PHP: PHP5, PHP7 * MySQL: optimisation, speed up, complex queries * API's: design and various integrations: Quickbooks, Expedia, Highrise, Airtable, Zapier, Google and many more, * JavaScript, ECMA6, React.js, Canvas * Drupal: Drupal 7, Drupal 8 * Wordpress * Apache SOLR * Chess: Stockfish, * ImageMagick, * CRM, * OSTicket Businesses I am usually a good match for: * Sport: tennis, chess, ski, freeride, snowboard, gym, fitness * Travel: booking engines, travel websites To take this chat to the next level, here's what you should do next: Let's see if we're the right fit. If you're looking for a tailored IT system for your business and a developer that will bring you a productivity boost and more results, we're aligned. To get the conversation started, hit the Hire Now button in the top-right corner. P.S. I travel a lot. No matter what country you are from, feel free to reach out - I may already know how to say 'hello' in your language! :) Jacek Francuz

I am a web developer with 6 years of commercial experience. My main field of competence is PHP/Laravel, but I am also fluent in JavaScript and have a good eye for design. I know how to deliver a fully functional application, as many of my previous projects were my sole responsibility. Technical expertise: - E-learning Applications Development - Online Shops Applications Development - API Development - Creating static websites Technology stack: - Backend: Laravel 9, PHP 8 - Frontend: Vue, Vuex, Nuxt.JS, React JS, jQuery, Bootstrap, Tailwind, ElementUI, HTML 5, CSS 3 - Databases: MySQL, MariaDB - Version Control System: Git, GitLab - Issue Trackers: Jira, Trello, Redmine - Others: PHPStorm, Sublime Text Looking forward to our cooperation! Piotr

Full Stack Developer & AI Developer / AI SaaS Developer — I'm a Web Application Developer & AI Engineer focused on AI Solutions & AI SaaS Development. Strong skills as an AI SaaS Architect, Senior Python Developer, and React Developer. Top Rated Plus | 100% Job Success | Only 5-star reviews ⭐⭐⭐⭐⭐ You'll get your AI SaaS prototype in 2 days, your AI-Powered SaaS MVP or AI solution shipped in 6-12 weeks🚀 🎓 BACKGROUND I've Master’s in Data Science & AI, currently preparing a PhD in AI. I’m a Senior Full-Stack Developer / AI Developer & AI Solution Architect with more than 8 years across 60+ projects. 💬 "Ilya led the work as the AI SaaS solutions architect & AI full-stack engineer, taking ownership of the overall architecture and delivery. Ilya delivered as an AI SaaS developer — balancing product, engineering, AI work without losing speed or quality. Ilya was exactly the kind of fractional CTO & engineering partner I was looking for. Highly recommend Ilya" — Jake Kinzelberg, Founder, Insurance AI SaaS, USA 💬 "Thanks to Ilya for developing my AI-powered SaaS. Ilya proved himself as an excellent AI Software developer & fullstack developer, proposed a clean UI UX SaaS Web design, built a solid backend with Python FastAPI, a front end with React" — Dmitri Dalla-Riva, Founder of Aidtrade, Australia 🎯 WHAT I DO I ship production-grade AI SaaS / AI product end-to-end. You come to me when you need: 🔹 SaaS MVP in weeks — built on architecture that scales beyond the prototype 🔹 AI development, AI Integration, LLM integration — RAG pipelines, AI agent SaaS, Voice Agent 🔹 Full Stack development delivery — one senior point of contact, one accountable owner 🔹 A technical co-founder mindset — scoping the SaaS development, making architecture decisions, owning the result 🛠 HOW I WORK As a Senior Full Stack Developer (React Python), AI Architect, I lead a small team — Senior Backend Engineer (Python Node.js), Frontend (React Angular Next.js), Full Stack Developer AI (JavaScript Vue.js jQuery Bootstrap), AI/ML Engineer, Mobile App Developer (Flutter), UI UX designer / SaaS UX designer — all under my direct coordination. In my work as a Full Stack AI SaaS developer & Python developer, I act as your delivery manager: one point of contact, the delivery capacity of a small agency. I work with Founders as a long-term Partner — calm execution, clear communication 📌 AI-Powered SaaS Development As a Full Stack Web Developer / AI SaaS full stack developer / SaaS AI Software Architect, I design SaaS Startup MVP that scale beyond the first version — multi-tenant architecture, role-based access, billing, webhooks, pipelines 🔹 SaaS architecture → Multi-tenant SaaS, RBAC, OAuth2, Stripe, AI API Integration 🔹 SaaS data layer → PostgreSQL, Redis, Supabase, multi-tenant isolation 🔹 SaaS infrastructure → Docker, AWS, Azure, Vercel, Cloudflare, CI/CD 🔹 SaaS delivery & AI MVP Development → SaaS design, MVP-to-production in 6 weeks 📌 AI Software Development As an Anthropic / OpenAI Developer, Data Scientist & Machine Learning Engineer, I integrate LLM & RAG into SaaS & Websites 🔹 AI/LLM integrations → Claude, ChatGPT-5, LLaMA, Mistral — fine-tuning, prompt design 🔹 RAG & Vector DB → LangChain, FAISS, Qdrant, Pinecone, ChromaDB, pgvector — Voyage embeddings, hybrid search inside SaaS, AI SEO 🔹 Generative AI → Stable Diffusion, SDXL, LoRA — custom image pipelines 🔹 AI ML Engineer → AI automation, deep voice agent, Computer Vision, MCP integrations, dashboards, LLM-powered SaaS 📌 Full Stack Development / Web Application Development As an AI Machine learning / Python Full Stack Developer & React developer / Senior Web Developer Python, I own the SaaS product end-to-end — ReactJS Next.js frontends, Python FastAPI Node.js backends with Superbase; MERN stack, PHP, Webflow / WordPress developer. 🔹 Front end developer → React, Next.js, TypeScript, Tailwind CSS, JavaScript 🔹 Backend developer → Python FastAPI, Django, Node.js, REST API development, GraphQL APIs 🔹 Real-time → WebSockets, Server-Sent Events for streaming AI 🔹 Web Application architecture & Web Development → modular monorepos, microservices 🤖 SENIOR AI-AUGMENTED DEVELOPMENT As a Senior AI Engineer / Python Backend Developer, I use modern AI tools for faster AI development: GitHub Copilot for coding, ChatGPT for reasoning, Cursor for refactoring, Claude Code with MCP for architecture, Replit for prototype testing, Lovable for MVPs prototyping, Bolt.new for web app experiments, v0 by Vercel for UI generation 🏆 MY UPWORK TRACK RECORD ✅ Top Rated Plus Expert ✅ 100% Job Success Score ✅ $200K+ earned delivering SaaS & AI Solutions ✅ 16 completed Upwork jobs ✅ 5-star average rating ✅ Upwork Skill Certified — Python Developer; Back-End Development 🤝 LET'S WORK TOGETHER If you're building SaaS or AI solution — you need a technical partner who ships, owns, thinks like a co-founder — message me. You’re taken from idea to deployment — faster and smarter