• I developed and deployed a scalable React application using Next.js, resulting in a 30% increase in user engagement and a decrease in page load time by 40%.• Test-driven development principles (TDD) used to create unit tests for critical components, resulting in a 50% reduction in bugs and an improvement in overall code quality.• Refactoring legacy PHP Laravel code for fast, scalable and practical new technologies using SSR, TDD and DDD, micro services, containers, CD CI, etc, agile development and best practices using tools such as Typescript, React.js and Node.js. This solution optimized SEO by 50%, overall user experience by 70%, and response time by 10x in some cases.• Full-featured, fully customized, and well-performing web applications for client companies around the world. Providing security and performance for more than 50 thousand users per day.• I presented and applied a solution using computer vision and AI to streamline a process of reading and validating invoices. This solution increased the efficiency from 9% to 89% and the speed using parallel and concurrent computing in 5x.