Marian Wielkopolski

Optimized front-end performance by reducing load times by 50% through refactoring and implementing lazy loading, improving user retention. Built interactive web applications focused on UX and performance using React, Vue.js, Material UI, and Bootstrap. Developed and deployed a scalable micro-front-end solution with React hooks, reducing server requests by 30% and improving responsiveness. Led development and customization of multiple Shopify-based e-commerce sites using Shopify Liquid (themes/templates) and APIs. Implemented code-splitting/lazy loading, optimized state variables, and pagination to reduce page load times by ~30% and improve engagement. Wrote unit tests with Jest/Enzyme and React Testing Library (~80% coverage). Improved accessibility by applying best practices and recommendations. Worked with backend engineers and clients; contributed to Node/Express and AWS Lambda APIs and participated in an e-commerce platform using React (front end) and Laravel/PHP (back end).

Developed, tested, and maintained systems written in React, TypeScript, and Laravel. Installed, configured, and maintained React/Laravel/PHP/Apache/MySQL on AWS (EC2, S3). Collaborated with design/development teams to apply accessible design principles. Converted React class components to functional components using hooks and TypeScript. Built an inventory management system with significant business logic. Integrated backend APIs using Laravel and other technologies (including .NET/Java). Developed landing pages using React Material UI. Worked with HTML5/CSS3/JavaScript, SASS/LESS, and Vue. Optimized and customized Shopify/WordPress/WooCommerce stores for SEO, conversion, and client requirements; integrated third-party APIs for donations, events, and social media/advertising. Architected a Python backend API solution to optimize data flow/query performance, improving retention and conversion. Implemented CI/CD pipelines to speed release cycles and improve QA.

Analyzed and optimized a real estate database system, reducing listing processing time by 15% and increasing property turnover by 30%. Built and maintained front-end applications using React/Redux, HTML/HTML5, CSS/SCSS, and Ant Design. Developed RESTful APIs using Node/Express to integrate with back-end services. Improved front-end performance using lazy loading, React Context APIs, PureComponent, and pagination. Implemented authentication/authorization using session/cookie approaches. Integrated REST endpoints and third-party APIs. Participated in testing/code reviews and collaborated closely with engineers, designers, and stakeholders to improve delivery efficiency and integration.