Oleksandr L.

Full-Stack & AI Engineer | Automation & SaaS, B2B Systems | QA (ISTQB)

I'm a Top Rated freelancer specializing in production level systems across Full-Stack, SaaS, B2B platforms, AI integrations and automation heavy applications. I build production systems that don't break under real usage and hold up under real users, real data and real business pressure. My work sits at the intersection of Full-Stack engineering, AI systems, CMS platforms and business critical integrations. I focus on building applications that are stable, scalable and actually usable in real world environments. * On the frontend I build modern web applications using #React, #Next.js, #Angular, #Laravel and #Vue.js with #Typescript, #Tailwind CSS and scalable component based architecture. I focus on #clean UI, #responsive layouts, #performance optimization, #accessibility and smooth user experience across desktop and mobile. I also work with #dashboard systems, #SaaS platforms, #real interfaces, #authentication flows and complex frontend state management. *On the backend I design and develop scalable systems using #Node.js, #Python and #Go with #PostgreSQL, #Supabase, #MongoDB and #REST/GraphQL APIs. My work includes #authentication systems, role based access control, #payment integrations, #automation workflows, #file handling, #API architecture, #database design and #cloud deployment. I focus heavily on maintainability, security, performance and building backend infrastructure that can scale without becoming difficult to manage later. * On the CMS side I work extensively with #Shopify and #WordPress including #custom theme development, #storefront customization, #Shopify Liquid, #App integrations, #WooCommerce, #Elementor, #Divi, #WPBakery and #performance optimization. I also handle #CMS migrations, #responsive redesigns, #SEO friendly structures and ongoing maintenance for production websites and eCommerce stores. * On the Automation & B2B system side I build workflow automation and integration systems that connect business tooles into unified processes. # API integrations(thrid party SaaS systems, CRMs, internal tools) # Workflow automation pipelines # Data synchronization systems # Event based automation # Scheduled jobs # Webhook orchestration # ETL-style data flows # Reporting automation and system to system communication design I specialize in reducing manual business operations by turning them into automated, reliable backend workflows. Where I bring extra value is in AI and system design. I don't just plug in APIs. I design AI features that fit into the product. # LLM integrations & LLM based workflow design for real workflows # Retrieval augemented systems and internal knowledge tools # AI driven reporting and automation pipelines # Structured, predictable outputs for business use # OpenAI API integration # Prompt-to-structured-output systems # RAG & vector database concepts I also work with SAP integrations and B2B data flows, connecting external systems, APIs and enterprise tools into a clean, reliable arhcitecture. This includes handling structured data, automations and backend logic that supports business operations. My QA background shapres everything I build. I'm ISTQB certified and experienced in both manual and automation testing using Java and Python, along with tools like Locust and Gatling for performance and load testing. *** I validate how they behave in real world conditions. This means after delivery, deployment, systems are tested with a quality focused mindset. I focus on edge cases, performance issues, API reliability and user flow stability are all considered before delivery. *** If you're building something that needs to be reliable, scalable and actually used by customers or internal teams, I can help you get it there. Regards, Oleksandr.