Hire the Best SaaS Developers
in Poland

I help founders and startups turn ideas into working digital products — fast, structured, and ready to scale. I specialize in building MVPs and SaaS applications using React and Node.js, with a strong focus on clean architecture, scalability, and user experience. I also have experience building: multi-tenant SaaS platforms, ERP systems, ESG-related products, and long-term scalable applications with complex business logic. I use AI-assisted development tools to speed up delivery, improve system design, and structure scalable architectures more efficiently. What I do: - MVP development from idea to production - SaaS and multi-tenant platforms - ERP / dashboard / internal tools - Backend architecture (Node.js / NestJS / GraphQL) - Frontend apps (React / Next.js) - API design and system scaling Tech Stack: React, Next.js, Astro, TypeScript, Node.js, NestJS, GraphQL, REST APIs, PostgreSQL, Prisma, MongoDB, Docker, CI/CD

𝗧𝗼𝗽 𝗥𝗮𝘁𝗲𝗱 𝗣𝗹𝘂𝘀 𝗼𝗻 𝗨𝗽𝘄𝗼𝗿𝗸, 𝘁𝗼𝗽 𝟯% 𝗴𝗹𝗼𝗯𝗮𝗹𝗹𝘆 ⚡ WHAT YOU GET ✔️12+ Full Stack Developer React Node | AI development | SaaS Developer | MERN stack ✔️60+ delivered projects across AI SaaS, CRM systems, dashboards, automation platforms, healthcare, legal tech, real estate, e-commerce, trading software ✔️15+ AI-powered SaaS MVPs, AI CRM systems, RAG tools, OCR/PDF processing, OpenAI and Claude integrations built from validation to launch ✔️25+ scalable React, Next.js, Node.js, Python AI backend, PostgreSQL, Stripe, AWS, Docker builds, full technical ownership, secure architecture, production-ready delivery as a Full Stack AI SaaS Developer ⚡ ACHIEVEMENTS | CLIENT WINS FROM AI SAAS & FULL STACK DEVELOPMENT ✔️26-day ROI recovery recruitment agency launched a Recruiting SaaS Platform with CRM automation and 2x faster candidate workflows ✔️93% faster estimation construction business reduced quoting time from 8 hours to 30 minutes with a custom Construction Estimator Web App ✔️#4 Product of the Day legal tech founder launched an AI Legal Assistant, RAG-powered document search, OpenAI integration, AI workflow automation ✔️5+ secure healthcare platforms healthcare med spa businesses improved provider/patient workflows with role-based access, admin dashboards, API integration ✔️10+ CRM & trading systems replaced manual operations with with custom CRM platforms, trading dashboards, reporting tools, scalable workflow automation ⚡As a Full stack AI SaaS developer I can support with: ✔️ AI-powered SaaS MVPs, product validation ✔️ AI agent workflow platforms, workflow automation system ✔️ AI-powered Custom CRM system, platform ✔️ AI-enabled admin dashboard, panel, machine learning ✔️ Role-based workflow platform secure permissions ✔️ Secure multi-user web application, scalable backend system ✔️ Booking & scheduling platform service businesse ✔️ Provider / patient workflow systems healthcare solution ✔️ Multi-stage automation workflows complex processe ✔️ RAG-powered document intelligence, search system ✔️ LLM-powered data processing using openai, modern AI tool ✔️ AI-assisted analytics, reporting ✔️ OCR and PDF processing pipeline ✔️ Rule-based insight engines ✔️ Secure backend API development, Third-party API integration ✔️ Multi-tenant SaaS platforms workspace isolation ✔️ Dashboard, data visualization system ✔️ HIPAA / GDPR-compliant platform ⚡ MY CORE STACK as a Full stack Web Developer | Full stack developer React Node | Full stack Developer AI React, Next.js, Node.js, Python, JavaScript, Supabase, PostgreSQL, MySQL, MongoDB, AWS, Docker, nginx, Stripe , AI tools like Openai, Claude, LangChain. I also work with laravel, PHP when a project requires a Full stack developer laravel or integration into an existing system. As a Full stack developer SaaS ( full stack developer ai ) I cover full product delivery: frontend, backend, infrastructure, APIs, and AI logic. I can work as a React developer, Front end developer, Backend developer, Web developer python, React web developer, Full stack web developer depending on the scope. On the frontend, I a work with HTML, CSS 3, Tailwind CSS, Vue.js, Angular, Bootstrap for specific stacks or legacy support. For SaaS products, I often work with full stack node.js react development, building React + Node.js SaaS applications with dashboard, admin panel, and secure APIs. I also work as a Full stack developer node | Full stack developer node js, focusing on performance and scalable architecture. When AI is involved, I support projects as a python developer with Python AI backend development, including RAG systems, OCR pipelines, document processing, intelligent automation I also have experience working with mobile app development and can contribute as a React Native developer, building cross-platform apps, react native integrated with backend systems and APIs In addition, I’ve worked as a full stack developer shopify, wordpress developer workflows, python full stack developer, front end developer react, full stack developer php and niche integrations, including Lazada developer-related marketplaces, helping businesses extend their platforms with custom features, payments and automation. What sets me apart is product thinking. As a technical partner, cto-level contributor, I help define Software Architecture & Design, avoid unnecessary complexity, build solutions that are ready for real users I also collaborate on web design, ui ux web design, ux designer, ui ux web designer workflows to ensure products are intuitive and easy to use If you need full stack web development, full stack saas architecture, AI-powered features, reliable Full stack website developer, I can help you build, scale your product I am especially strong as a Full stack developer saas, Full stack AI SaaS developer, complex platforms, AI-driven products 💬 Message me with your idea - I’ll share a relevant case, technical approach, clear estimate from a full stack developer

Helping startups and growing companies launch polished, scalable products - fast. ⚡️𝐒𝐞𝐫𝐯𝐢𝐜𝐞𝐬 𝐭𝐡𝐚𝐭 𝐈 𝐨𝐟𝐟𝐞𝐫 𝗦𝗮𝗮𝗦 𝗣𝗿𝗼𝗱𝘂𝗰𝘁 𝗗𝗲𝘃𝗲𝗹𝗼𝗽𝗺𝗲𝗻𝘁 As a Full Stack Developer, I build complete SaaS platforms, not just features. I handle user authentication, subscription billing with Stripe, admin dashboards, usage tracking, multi-tenant architecture, and role-based access control - building clean systems that scale with your user base. 𝗙𝘂𝗹𝗹-𝗖𝘆𝗰𝗹𝗲 𝗦𝗼𝗳𝘁𝘄𝗮𝗿𝗲 𝗗𝗲𝘃𝗲𝗹𝗼𝗽𝗺𝗲𝗻𝘁 As a Full Stack Developer and Mobile Developer, I handle the entire lifecycle of your React Native, React, or Next.js project from the first prototype to post-launch updates. I make sure the product stays stable, secure, and user-friendly across all web and mobile platforms. 𝗠𝗩𝗣 𝗗𝗲𝘃𝗲𝗹𝗼𝗽𝗺𝗲𝗻𝘁 As a Full Stack Developer, I help startups ship fast but solid. I’ve launched multiple MVPs from scratch that helped founders validate their ideas, pitch investors, and scale on top of clean architecture, quick iterations, and strong technical foundations. 𝗠𝗼𝗯𝗶𝗹𝗲 & 𝗪𝗲𝗯 𝗨𝗜 𝗜𝗺𝗽𝗹𝗲𝗺𝗲𝗻𝘁𝗮𝘁𝗶𝗼𝗻 As a Mobile Developer and Full Stack Developer, I deliver pixel-perfect Figma-to-code implementation. I build sharp, responsive UIs with smooth animations and clean interactions, maintaining a strict mobile-first engineering approach. 𝗪𝗲𝗯𝘀𝗶𝘁𝗲𝘀 & 𝗟𝗮𝗻𝗱𝗶𝗻𝗴 𝗣𝗮𝗴𝗲𝘀 As a Full Stack Developer, I build high-converting landing pages, marketing websites, Shopify storefronts, and custom company pages. Using React, Next.js, Tailwind CSS, or simple static stacks, I deliver SEO-optimized, blazing-fast, and easy-to-manage web properties. 𝗕𝗮𝗰𝗸𝗲𝗻𝗱 & 𝗔𝗣𝗜 𝗗𝗲𝘃𝗲𝗹𝗼𝗽𝗺𝗲𝗻𝘁 As a Full Stack Developer, I engineer solid, scalable backends built with Node.js, NestJS, or Express, backed by PostgreSQL or MongoDB databases. I design clean REST/GraphQL APIs, implement robust authentication, and integrate third-party services like Stripe, Firebase, and OpenAI. 𝗔𝗜 𝗜𝗻𝘁𝗲𝗴𝗿𝗮𝘁𝗶𝗼𝗻 As a Full Stack Developer, I integrate OpenAI and other LLM APIs into real production products, not just demos. I build practical AI features, custom chatbots, smart recommendation engines, prompt engineering workflows, and RAG pipelines. 𝗢𝗻𝗴𝗼𝗶𝗻𝗴 𝗦𝘂𝗽𝗽𝗼𝗿𝘁 & 𝗠𝗮𝗶𝗻𝘁𝗲𝗻𝗮𝗻𝗰𝗲 As a Full Stack Developer, I stick around after launch to fix bugs, optimize performance, and scale your product as your business requirements evolve and user base grows. 🌟 𝐂𝐥𝐢𝐞𝐧𝐭 𝐒𝐮𝐜𝐜𝐞𝐬𝐬 𝐒𝐭𝐨𝐫𝐢𝐞𝐬: Denys is a great contractor - very capable and eager to get the job done properly. He communicates well and is knowledgeable - ⭐⭐⭐⭐⭐ I can honestly recommend Denys as developer and the most responsible, proactive freelancer I’ve ever met. Quick answers and responses, step by step demo calls, fair price, strong skillset, fluent English - ⭐⭐⭐⭐⭐ Denys is an absolutely phenomenal engineer. I say this as someone who worked with him project to project over many years as a supervisor and then eventually a co-worker. Hands down the best Upwork hire I've had!!! - ⭐⭐⭐⭐⭐ 𝗪𝗵𝘆 𝘄𝗼𝗿𝗸 𝘄𝗶𝘁𝗵 𝗺𝗲? I own projects - not just code tasks. I think like a founder - not just a dev. I deliver fast, communicate clearly, and stick to timelines. I’m in this for the long term, not one-off jobs. 📩 Send me a message or invite - happy to jump on a quick call and see if I'm a good fit for your project. SaaS Development, SaaS Product Development, B2B SaaS, B2C SaaS, Subscription Platform Development, Multi-Tenant Architecture, MVP Development, Startup Development, Rapid Prototyping, Product-Market Fit, Full-Cycle Software Development, End-to-End App Development, Mobile App Development, iOS App Development, Android App Development, React Native App Development, Flutter App Development, Cross-Platform App Development, Hybrid App Development, Mobile App Design, Mobile App UX/UI Design, App Performance Optimization, App Scalability, Web Development, React, Next.js, Tailwind CSS, Landing Page Development, Shopify Development, SEO Optimization, Backend Development, Node.js, Nest.js, Express.js, RESTful API, GraphQL API, PostgreSQL, MongoDB, Database Design, API Integration, Third-Party Integrations, Authentication & Authorization, Role-Based Access Control, Stripe Integration, Payment Integration, Subscription Billing, Firebase Integration, Firebase Cloud Firestore, Firebase Cloud Messaging, Push Notifications, AWS, AWS Mobile Services, Cloud Architecture, Serverless Architecture, AI Integration, OpenAI API, LLM Integration, Prompt Engineering, Conversational AI, Chatbot Development, Recommendation Systems, RAG (Retrieval-Augmented Generation), TypeScript, JavaScript, Feature Integration, App Maintenance, Ongoing Support, Bug Fixing, Software Development Life Cycle, Agile Development, Git, GitHub, CI/CD Updated July 2026

I am a Senior AI, Web & Mobile Engineer, building intelligent SaaS platforms, immersive web experiences, and cross-platform mobile apps that help businesses scale faster and cut costs. With 8+ years of experience across AI, web, and mobile development, I've delivered 40+ successful projects for startups and enterprises. I build production-ready, data-driven software - not just demos. My solutions think and learn: for example, I've developed AI order-processing engines that analyze 25,000+ SKUs and cut data-entry time by 97%, and voice-based chatbots that reduced customer service workloads by 50%. 🧠 𝐂𝐨𝐫𝐞 𝐄𝐱𝐩𝐞𝐫𝐭𝐢𝐬𝐞 AI-driven SaaS & Web Apps, Cross-Platform Mobile Development (RN & Flutter), 3D & Interactive Web (Three.js), Multi-Agent Automation, LLM Integrations, Predictive Analytics, FinTech / Healthcare / CRM systems. I design end-to-end solutions: from scalable backends to intuitive UIs and immersive frontends. ⚙️ 𝗧𝗲𝗰𝗵 𝗦𝘁𝗮𝗰𝗸 🤖 𝗔𝗜/𝗠𝗟: LangChain, LangGraph, OpenAI/GPT-4o, Claude API, Gemini, LlamaIndex, Hugging Face, TensorFlow, PyTorch, Scikit-learn, Whisper, Stable Diffusion, RAG (Pinecone, Weaviate, FAISS, ChromaDB), CrewAI, AutoGen. 🖥️ 𝗙𝗿𝗼𝗻𝘁𝗲𝗻𝗱: React, Next.js 14, TypeScript, Tailwind CSS, shadcn/ui, Framer Motion, Redux, Zustand, Three.js, React Three Fiber, WebGL, GSAP, D3.js. 📱 𝗠𝗼𝗯𝗶𝗹𝗲: React Native, Flutter, Expo, Firebase, Push Notifications, App Store & Play Store deployment, deep linking, offline-first architecture. 🔧 𝗕𝗮𝗰𝗸𝗲𝗻𝗱: Node.js (Express, Nest.js), Python (FastAPI, Django, Flask), REST/GraphQL APIs, WebSockets, gRPC, microservices, event-driven architecture. ☁️ 𝗖𝗹𝗼𝘂𝗱/𝗗𝗲𝘃𝗢𝗽𝘀: AWS (Lambda, SageMaker, EC2, S3, RDS), Azure, GCP, Docker, Kubernetes, Terraform, GitHub Actions, CI/CD pipelines, Vercel, Railway. 🗄️ 𝗗𝗮𝘁𝗮𝗯𝗮𝘀𝗲𝘀: PostgreSQL, MySQL, MongoDB, Redis, Supabase, PlanetScale, Elasticsearch, vector DBs (Pinecone, Weaviate, FAISS). 🔗 𝗜𝗻𝘁𝗲𝗴𝗿𝗮𝘁𝗶𝗼𝗻/𝗔𝘂𝘁𝗼𝗺𝗮𝘁𝗶𝗼𝗻: Zapier, n8n, Make (Integromat), Airflow, Stripe, Twilio, SendGrid, Plaid, CRMs (HubSpot, Salesforce), Slack & Discord bots. 🚀 𝗦𝗲𝗿𝘃𝗶𝗰𝗲𝘀 𝗜 𝗣𝗿𝗼𝘃𝗶𝗱𝗲 ✅ AI SaaS platforms & LLM-powered products ✅ Chatbot & voice assistant development ✅ Cross-platform mobile apps (React Native & Flutter) ✅ 3D & interactive web experiences (Three.js / WebGL) ✅ Workflow automation & multi-agent orchestration ✅ Document analysis & RAG-based knowledge systems ✅ Custom NLP, computer vision & predictive analytics ✅ FinTech, Healthcare & CRM platform development ✅ API design, microservices & cloud infrastructure ✅ App Store & Play Store deployment & maintenance For example, I've built GPT-4 chatbots integrated into client CRMs, multi-tenant analytics dashboards, immersive 3D product visualizers, cross-platform mobile apps with 10k+ users, and automated data pipelines that increased efficiency by 60%. 💡 𝗪𝗵𝘆 𝗪𝗼𝗿𝗸 𝗪𝗶𝘁𝗵 𝗠𝗲 I focus on your business goals, not just code. You'll get a partner who can architect your product vision - through design, prototyping, and deployment - communicate clearly every step, and deliver a reliable, maintainable solution. 📩 If you want to integrate AI into your product, automate your operations, build a scalable web or mobile platform, or create immersive 3D experiences - let's chat. I'm happy to discuss your project and turn your idea into a fast, intelligent system.

I help founders and operations teams turn business processes into reliable web portals, internal tools, dashboards, and SaaS MVPs. My strongest area is backend-heavy development: Laravel, Symfony, Yii/legacy PHP when needed, API integrations, roles/permissions, workflows, reports, and data-heavy systems. For frontend, my strongest stack is Vue.js, with React as a secondary option. I am not just a coder. I usually start by understanding how your business works, what users need to do, which edge cases matter, and what reports or automation will save time. Then I help turn that into a clear prototype, first milestone, POC, or MVP. Recent examples: - Designed and built an insurance broker portal from scratch: roles, API integration with a policy issuing system, tariff calculation, policy issuing flow, commission management, and reports. The first policy was issued 2.5 months after the idea. - Built an AI chatbot system for a cosmetics e-commerce store with product recommendations, catalog Q&A, cart/order flow, Instagram Direct + Telegram integration, admin panel, dialog logging, vector search, Elasticsearch, PostgreSQL, and 20+ prompts/agents. Token cost per completed order flow was under $0.02. - Built and worked on analytics-heavy systems, including e-commerce dashboards with 10k+ daily orders, adtech systems with 10m+ daily views, and CRM/ERP-style workflows. What I can help with: - Business portals and internal tools from scratch - Workflow automation and role-based systems - SaaS MVPs and admin dashboards - Complex reports and analytics-heavy backends - Laravel/Symfony/Vue development - API integrations and business process automation - AI integrations when they bring real business value My preferred process for new products: 1. Discovery call to understand your idea and business flow. 2. Prototype or workflow description with clear business tasks. 3. Client approval and scope adjustment. 4. POC/MVP development. If the project needs UI/UX, I can involve a trusted designer while staying responsible for the technical delivery. I prefer to start with a small, useful first step: an audit, prototype, first milestone, or technical plan. If we work well together, I am open to long-term hourly work.

Welcome to my profile! 🔥 I help startups and global businesses (Pfizer, Deutsche Bank, ING, Upwork, KLM, Ford) build, scale, and support AI SaaS products faster, acting as a lead full stack developer and mobile app developer so you don't need to assemble a full team just to get moving. If your project needs a highly interactive frontend built by a specialist react developer, or use Vue and Angular, a scalable .NET or Golang architecture, a custom CMS handled by a senior wordpress developer, or a dedicated Back End Developer building secure Rust and Solana microservices, I cover it as your full stack developer and software developer, so you get one point of ownership instead of five disconnected specialists. My deep expertise in JavaScript, PHP, and AI integrations, combined with an understanding of SaaS sales and SaaS marketing, means the SaaS applications I build are engineered to actually convert and scale, not just function. ⭐ Certified full stack developer, React developer, software developer, & SaaS developer Top Rated+ 🏆100% full stack developer Success for every SaaS contract utilizing React, Vue, Angular, Node.js, Python, Golang, Rust ⭐ 5-star Rating for web, mobile app developer projects, AI, Web3 Solana, and SaaS 💰 $300K+ earned delivering excellence as an elite full stack developer, web developer, software developer, and wordpress developer. Whatever stage your product is at, I bring extensive full stack developer and software developer expertise across Web, Mobile, and SaaS platforms to get you there, seamlessly integrating AI models and Web3 components (including Solana smart contracts) into robust web systems built for your business. Whether architecting a new SaaS platform in .NET, optimizing core financial engines in Rust or golang, deploying a custom theme as a wordpress developer, boosting technical infrastructure for FinTech, MarTech, PropT SaaS products, or scripting in Python for complex data processing. My full stack developer and SaaS developer approach covers every Web, Mobile, AI, Data, Web3 projects domains. My skills as a full stack developer, React developer, software developer, SaaS developer, web developer, mobile app developer, and Back End Developer: ✅React (lead react developer, MERN stack) ✅Vue ✅Angular ✅Node.js ✅Python ✅Golang ✅.NET (Web APIs, legacy migrations) ✅Rust (memory-safe modules, solana ecosystems) ✅PHP (stable databases) ✅JavaScript (core & advanced ecosystems) ✅WordPress / Custom CMS ✅AI Adoption & Integrations ✅Web3 / Solana smart contracts ✅iOS/Android (mobile app developer) ✅Agile & Scrum/Kanban delivery Stack of technologies I use as your full stack developer: ✅ Frontend: React, Vue, Angular ✅ Backend & APIs: Node.js, .NET Web APIs, Golang, PHP ✅ Data & scripting: Python (complex data processing) ✅ Blockchain: Rust-based Solana microservices, Web3 smart contracts ✅ CMS: bespoke WordPress builds and custom themes ✅ AI: model integrations for smart SaaS features ✅ Mobile: iOS/Android builds as mobile app developer By combining core JavaScript, advanced React/Vue/Angular ecosystems, scalable Node.js and Golang microservices, stable PHP databases, and smart AI features, I deliver exactly what you need from a top-tier full stack developer, cross-platform mobile app developer, software developer, and Back End Developer. Industries where I bring solid full stack developer, software developer, and SaaS developer experience: ✅AI Development, AI Agents, AI Integration, Web3, Blockchain ✅Data Engineering (Cloud, AI, ML, Vector, SQL, NoSQL) ✅Finance (FinTech SaaS, data analytics via Python, Golang, Rust) ✅PropTech (SaaS, CRM, Rich UIs via JavaScript, Vue, Angular, React) ✅HRTech/EdTech (SaaS solutions) ✅Travel/Hospitality (SaaS platforms) ✅eCommerce (web portals via .NET, PHP) As a dedicated lead React full stack developer, react developer, Node.js Architect, Back End Developer, and strategic SaaS developer, I blend AI performance, Golang APIs, and Rust (including Solana blockchains) into your traditional SaaS workflows — as your full stack developer, web developer, and mobile app developer, all in one. 🔥 Backed by certification as a Full Stack developer Engineering and Solution Architect Expert (Ph.D. CS, PMP, CSP, CSM, CSPO, ICP-PPM, MCP), I deliver Agile/Scrum SaaS solutions as a lead full stack developer, dedicated react developer, software developer, and saas developer focused on turning your web, AI, React, Vue, angular, Rust,Solana, Golang, and .NET goals into a shipped product. 🔥 Managing cross-functional teams as a full stack developer, I ensure strict coding best practices across dynamic React, Vue, and angular UIs, iOS/Android builds guided by a senior mobile app developer, Node.js, Golang, and PHP backends, Web3 Solana integrations, legacy .NET migrations, bespoke CMS builds managed by a wordpress developer, and sophisticated Python integrations designed to maximize your Saas sales and Saas marketing ROI *Updated: 29.07.2026