Denis S.

Senior AI Engineer | Full Stack Developer |Full-Stack Web Developer

Upwork changes its algorithm every few months.... Clean architecture has survived for decades. We bet on the second one. ⚡ Building 𝐀𝐈-𝐩𝐨𝐰𝐞𝐫𝐞𝐝 𝐩𝐫𝐨𝐝𝐮𝐜𝐭𝐬, enterprise platforms, SaaS solutions, and scalable digital ecosystems 🔧 Using modern AI tools including Cursor, Claude Code, GitHub Copilot, GPT-4/GPT-4o, and Claude Sonnet/Opus 🤖 Experienced in AI agents, LLM integrations, AI automation, and multi-agent development systems 🚀 Accelerating development with 𝐀𝐈-𝐚𝐬𝐬𝐢𝐬𝐭𝐞𝐝 𝐞𝐧𝐠𝐢𝐧𝐞𝐞𝐫𝐢, agentic coding, and automation-driven workflows 💻 𝐖𝐇𝐀𝐓 𝐘𝐎𝐔 𝐀𝐍𝐃 𝐘𝐎𝐔𝐑 𝐓𝐄𝐀𝐌 𝐆𝐄𝐓 Full-Stack Web Development Master's - high-performance web application development utilizing React, Node.js, and PHP to build scalable SaaS, FinTech, and Enterprise software. AI & Automation Systems Innovators - custom LLM applications, RAG pipelines, and intelligent workflow automations seamlessly integrated into your infrastructure. 📊 𝐀𝐂𝐇𝐈𝐄𝐕𝐄𝐌𝐄𝐍𝐓𝐒 𝐈𝐍 𝐍𝐔𝐌𝐁𝐄𝐑𝐒 (𝐁𝐔𝐒𝐈𝐍𝐄𝐒𝐒 & 𝐒𝐘𝐒𝐓𝐄𝐌 𝐈𝐌𝐏𝐀𝐂𝐓) 25+ years, 50,000+ engineering hours, 200+ successful launches delivered as a Senior Full Stack Developer and tech leader across global industries. ◾ Full-Stack Web Development for Enterprise & SaaS Platforms: Engineered and launched custom AI-powered SaaS platforms that scaled to millions of active users with 99.99% operational uptime. Accelerated product development cycles by 40% by deploying optimized React component libraries and agile workflows. Backend Architecture & API Engineering (Node.js & PHP): Reduced server infrastructure costs by 50% by migrating legacy monoliths into scalable microservices using Node.js, NestJS, and PHP. Optimized heavy data-processing pipelines, reducing database latency by 70% via tailored PostgreSQL, MongoDB, and MySQL schemas. ◾ AI App Development & Workflow Automation: Developed and integrated proprietary OpenAI GPT, Claude, and Gemini models into operational CRMs, increasing client workflow efficiency by 180%. Successfully deployed secure, HIPAA-compliant healthcare applications and high-security FinTech platforms with built-in Stripe / PayPal integrations. 🎯 𝐖𝐇𝐄𝐑𝐄 𝐖𝐄 𝐃𝐄𝐋𝐈𝐕𝐄𝐑 (𝐂𝐎𝐑𝐄 𝐄𝐗𝐏𝐄𝐑𝐓𝐈𝐒𝐄) As a Full Stack Developer & Solution Architect: I handle the full cycle of Full-Stack Web Development, defining technical roadmaps, designing scalable web applications, and ensuring bulletproof cyber-security protocols. As a Front-End Development Expert: Crafting pixel-perfect, highly responsive user interfaces using React, Next.js, TypeScript, Vue.js, and Angular to ensure maximum conversion rates and premium UX. As a Back-End Development Authority: Designing ultra-fast APIs and core services with Node.js (Express/NestJS), PHP, Python (FastAPI/Django), and modern Serverless Stack architectures. As a Cloud & DevOps Engineer: Implementing enterprise-grade cloud deployments via AWS, Google Cloud, and Azure, utilizing Docker, Kubernetes, and automated CI/CD pipelines. 🛠 𝐓𝐄𝐂𝐇 𝐒𝐓𝐀𝐂𝐊 & 𝐀𝐑𝐂𝐇𝐈𝐓𝐄𝐂𝐓𝐔𝐑𝐄 𝐄𝐂𝐎𝐒𝐘𝐒𝐓𝐄𝐌 Frontend Suite: React, Next.js, TypeScript, Tailwind CSS, Vue.js, Angular, Responsive Web Design. Backend Core: Node.js, NestJS, Express.js, PHP, Python, FastAPI, Django. Databases & Caching: PostgreSQL, MongoDB, MySQL, Redis. APIs & Global Integrations: REST APIs, GraphQL, Webhooks, Stripe, PayPal, Twilio, SendGrid. Cloud & DevOps Platform: AWS (Amazon Web Services), Google Cloud, Azure, Docker, Kubernetes, Jenkins, GitHub Actions CI/CD. 🧠 𝐃𝐄𝐄𝐏 𝐈𝐍𝐃𝐔𝐒𝐓𝐑𝐘 𝐄𝐗𝐏𝐄𝐑𝐈𝐄𝐍𝐂𝐄 AI & SaaS Startups: Rapid MVP development, RAG pipelines, AI chatbots, and predictive analytics tools. FinTech & E-commerce: High-load payment gateways, customized checkout solutions, compliance, and ledger systems. Healthcare & PropTech: Automated workflow systems, secure patient portals, CRM platforms, and real-time data visualization dashboards. Enterprise Automation: Heavy B2B platforms, marketplaces, and cross-platform integrations. ⚡ 𝐇𝐎𝐖 𝐖𝐄 𝐖𝐎𝐑𝐊 𝐓𝐎𝐆𝐄𝐓𝐇𝐄𝐑 Strategic Discovery: As a CTO, I align your business goals, success metrics, and timeline constraints before writing a single line of code. Architecture Blueprinting: We map out the core database schemas, React frontend components, and Node.js / PHP API flows to ensure long-term scalability. Agile Iteration: Backed by the senior engineering powerhouse at Onix-Systems, we deliver high-velocity sprints with predictable, production-ready releases every 2 weeks. DevOps & Launch: Secure deployment across AWS/GCP/Azure with ongoing tech partnership and proactive optimization based on product metrics. Looking for a Senior Full Stack Developer and a Full-Stack Web Development team to turn your complex concept into a world-class, scalable web platform? 𝐋𝐞𝐭’𝐬 𝐜𝐨𝐧𝐧𝐞𝐜𝐭! Send over your project brief, scope, or existing codebase notes, and I’ll provide a high-level strategic roadmap for your next big launch. ☎️