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Summary As a versatile Web Developer and Test Automation Specialist, I bring expertise in a range of technologies crucial for crafting exceptional digital experiences. Proficient in JavaScript (JS), React.js, HTML, CSS, and Selenium for test automation, I excel in building dynamic and responsive web applications while ensuring robust automated testing frameworks. With a solid understanding of SQL, I proficiently handle databases to optimize data-driven functionalities. My familiarity with GitHub streamlines collaborative development and version control. Moreover, my grasp of Scrum/Agile methodologies enables me to seamlessly integrate into agile teams, ensuring efficient project delivery and adherence to timelines. I'm passionate about leveraging my technical skills and methodologies to drive innovation and deliver top-notch solutions. Whether it's frontend development, test automation, or utilizing agile methodologies, I'm dedicated to exceeding client expectations and contributing to impactful projects.

I am a software developer with over 12 years of experience creating and maintaining applications across a wide variety of projects and product spaces. Focused on JavaScript/TS, mainly React and Node.js, with an AI-first development workflow built around Claude Code and Cursor. I've been a full-time freelancer for over 10 years, working with clients ranging from small startups to Fortune 100 companies. AI-assisted development is at the core of how I work today — the majority of code I ship is built with LLMs in the loop, covering end-to-end feature development, large-scale refactors, and automated workflows. I know how to get the most out of frontier models while keeping code quality high: reviewing, validating, and correcting AI output rather than trusting it blindly. I'm also experienced in auditing and hardening AI-generated and vibe-coded codebases, taking them from rapid prototype to production-ready. Beyond tooling, I've built AI-powered products directly — LLM integrations, agentic workflows, RAG pipelines, and AI-driven content processing. I can build any project from the ground up and have experience with all stages of development of enterprise-grade platforms — from developing an MVP, reviewing UI designs and technology choices, getting it ready to release, releasing the platform, and maintaining it. I am skilled at writing well-designed, testable, and efficient code using current best practices. I am a hard-working and responsible person, able to work by myself or in a team.

Need a production-ready SaaS or MVP built fast and without technical debt? With 7+ years of Full Stack experience, I specialize in building scalable SaaS products and MVPs. My expertise is built on a strong Node.js foundation and extensive experience with Headless CMS architectures, allowing me to bridge the gap between complex backend logic and modern frontend performance. What I Can Do For You • Build or improve your web app (React / Next.js) • Set up or optimize your backend (Node.js / Supabase / PostgreSQL) • Fix bugs, optimize performance, or refactor code • Develop MVPs and prototypes quickly • Integrate external APIs or third-party services • Deploy apps to Vercel, Netlify, or custom hosting Why Clients Work With Me • Clear, simple communication • Predictable, organized workflow • Fast delivery and frequent updates • Clean, maintainable code that’s easy to continue building on Recent Work • Built and launched a production-ready nutrition tracking app (similar to MyFitnessPal) using React Native, Node.js, Supabase, and PostgreSQL • Developed multiple admin dashboards and internal tools (React, Next.js, Tailwind) • Created custom APIs and backend services (Node.js, REST, GraphQL) If you want a reliable developer who delivers results without drama, let’s talk.

Specialize in building full-stack React + Supabase SaaS products with AI integrations, designed for startups that want to move fast and scale properly. To ship faster than most developers, I built two internal systems: 1. React + Node.js + Supabase SaaS Starter Production-ready Supabase architecture (Auth, Postgres, Realtime, Edge Functions) with React / Next.js or Node.js. It has Cursor AI rules in itself so if you want whole project vibe coded , it will still follow good code practice. Perfect for launching micro SaaS products in days instead of months. 2. Lovable → Next.js AI Converter Many founders build MVPs with Lovable, but hit SEO and scalability issues. I built an AI powered converter that transforms Lovable (React/Vite) components into clean Next.js architecture using AI workflows. This + using Cursor AI allows rapid MVP validation - proper React SaaS architecture without rewriting everything manually. ━━━━━━━━━━━━━━━━━━ Experience With 8+ years on Upwork, I’ve built and maintained SaaS platforms, Supabase systems, AI-powered applications, dashboards, and internal tools used in real production environments. Clients hire me when they need: A serious React SaaS developer A Supabase full stack expert An AI focused product engineer Someone who takes ownership and works independently Clear communication ━━━━━━━━━━━━━━━━━━ What I Build (React + Supabase + AI Focus) React SaaS MVPs powered by Supabase Full-stack Supabase applications AI-powered SaaS platforms (OpenAI integrations) Internal tools built with React + Supabase SaaS dashboards & product dashboards Customer portals & role-based systems Subscription-based React apps (Stripe + webhooks) Modern startup platforms using Next.js + Supabase AI-enhanced business automation tools ━━━━━━━━━━━━━━━━━━ ⭐⭐⭐⭐⭐ "We were very lucky to have come across Djordje, his skills, quality of work and his personality are second to none. Highly recommended !!!" ━━━━━━━━━━━━━━━━━━ Tech stack: Frontend: React (Server Components, Server Actions) Next.js (App Router, SSR, edge-ready apps) TypeScript (strict architecture) TailwindCSS (scalable design systems) TanStack Query Zustand Vite React Native + Expo Backend / Full-stack: Supabase (Postgres, Auth, Realtime, Edge Functions) Node.js Express FastAPI PostgreSQL REST APIs Webhooks Stripe integrations AI & Product Layer: OpenAI API AI-native UX Prompt engineering LLM integrations Cursor & AI-assisted workflows "Vibe coding" product iteration mindset Infrastructure: Vercel Docker AWS Google Cloud Testing: Jest React Testing Library Playwright Cypress ━━━━━━━━━━━━━━━━━━ Why clients work with me: Strong React + Supabase expertise Deep experience with Tailwind + modern UI systems Production-level TanStack usage Clear communication Independent ownership Startup speed with senior-level architecture If you’re building something modern, especially with React, Supabase, Tailwind, TanStack, or AI integrations - let’s talk.

𝗜 𝗯𝘂𝗶𝗹𝗱 𝗮𝗻𝗱 𝘀𝗰𝗮𝗹𝗲 𝗽𝗿𝗼𝗱𝘂𝗰𝘁𝗶𝗼𝗻 𝘄𝗲𝗯 𝗮𝗽𝗽𝘀 𝗳𝗼𝗿 𝗦𝗮𝗮𝗦, 𝗳𝗶𝗻𝘁𝗲𝗰𝗵, 𝗿𝗲𝗮𝗹𝘁𝗶𝗺𝗲, 𝗮𝗻𝗱 𝗱𝗮𝘁𝗮-𝗵𝗲𝗮𝘃𝘆 𝗽𝗹𝗮𝘁𝗳𝗼𝗿𝗺𝘀. 𝟭𝟬+ 𝘆𝗲𝗮𝗿𝘀 𝗶𝗻 𝗳𝗿𝗼𝗻𝘁𝗲𝗻𝗱, 𝟮𝟬+ 𝘆𝗲𝗮𝗿𝘀 𝗶𝗻 𝘀𝗼𝗳𝘁𝘄𝗮𝗿𝗲, 𝗠𝗮𝘀𝘁𝗲𝗿’𝘀 𝗶𝗻 𝗖𝗼𝗺𝗽𝘂𝘁𝗲𝗿 𝗦𝗰𝗶𝗲𝗻𝗰𝗲. Most of my work comes from long-term product development engagements where reliability, maintainability, and delivery speed matter. 𝗜 𝘄𝗼𝗿𝗸 𝗱𝗶𝗿𝗲𝗰𝘁𝗹𝘆 𝘄𝗶𝘁𝗵 𝗰𝗹𝗶𝗲𝗻𝘁𝘀 — 𝗻𝗼 𝗮𝗰𝗰𝗼𝘂𝗻𝘁 𝗺𝗮𝗻𝗮𝗴𝗲𝗿𝘀, 𝗻𝗼 𝗵𝗮𝗻𝗱𝗼𝗳𝗳𝘀, 𝗻𝗼 𝗼𝘂𝘁𝘀𝗼𝘂𝗿𝗰𝗶𝗻𝗴. 𝗥𝗲𝗰𝗲𝗻𝘁 𝘄𝗼𝗿𝗸: • Led frontend development for a cryptocurrency exchange platform across a 2,800+ hour engagement using React and TypeScript • Built and maintained a large-scale WebRTC livestream platform with realtime video and high-frequency UI updates for live stadium fan engagement (1,800+ hours) • Served as senior full-stack engineer for a risk management SaaS platform across a 750+ hour engagement • Built data-heavy financial dashboards and operational tools using React, Node.js, and SQL • Refactored and scaled React/Vite applications to improve maintainability, delivery speed, and performance • Delivered production-critical debugging and emergency fixes for live React applications under active customer usage 𝗦𝘁𝗮𝗰𝗸: • React / Next.js / TypeScript / Zustand / Redux / Tailwind • Node.js / Express / GraphQL / PostgreSQL • WebRTC / WebSockets / realtime systems • OpenAI APIs / AI integrations / workflow automation • Docker / CI-CD / GCloud Earlier experience includes Angular modernization and migration work. I typically work as the lead or primary engineer on projects. For larger scopes, I can bring in trusted senior developers I’ve worked with for years while remaining personally accountable for architecture and delivery. Send me your project brief and I’ll reply within 4 hours with a concrete implementation plan, risk assessment, and recommended next steps.

Passionate about creating intelligent, automated ecosystems that enhance productivity and transform the way users interact with technology. Focused on designing efficient, scalable systems that connect people, data, and processes seamlessly. Driven by a vision to simplify complexity, boost collaboration, and build solutions that empower continuous innovation and measurable impact.