GrailPay is a financial technology company founded in 2020, aiming to revolutionize business-to-business (B2B) payments by offering a low-cost, high-conversion pay-by-bank alternative to traditional card networks. By enabling direct bank account payments, GrailPay helps merchants reduce payment processing costs and enhances cash flow for small and medium-sized businesses (SMBs). GRAILPAY The platform provides comprehensive infrastructure for payment processing and short-term financing, including features like advanced authentication and data analytics. GrailPay's solutions are designed to eliminate fraud risk, accelerate cash availability, and reduce administrative costs. Additionally, the company offers instant approval for up to 90 days

- Designed a B2B payment processor widget using Remix.js, improving form submission speed and reducing errors, leading to a smoother checkout experience; - Built an SDK with TypeScript and Express to simplify client integration, reducing setup time from hours to minutes and improving adoption rates; - Led end-to-end testing implementation with Jest and Cypress, increasing test coverage from ~50% to 95%, reducing production bugs; - Enhanced internal QA tools, streamlining bug reporting and improving developer efficiency, leading to faster release cycles; - Implemented Redis caching, cutting API response times from ~1.5s to, improving overall system performance; -Optimized PostgreSQL queries with Prisma, reducing database query times by ~40%.

BigBI is a no-code, interactive visual ETL (Extract, Transform, Load) platform designed to empower business intelligence analysts and data scientists to efficiently build and manage big data pipelines without the need for coding. Key features of BigBI include: Visual Pipeline Construction: Users can create data pipelines through a drag-and-drop interface, simplifying the development process and reducing the time required to deploy data workflows. Real-Time Data Interaction: The platform allows for interactive debugging and real-time examination of data at each step of the pipeline, enhancing accuracy and confidence in data processing outcomes. Comprehensive Data Integration: BigBI supports a wide array of data sources and destinations

- Refactored state management, migrating from Context API to Redux, improving code maintainability and reducing re-renders in complex UI components; - Implemented secure JWT-based authentication with NestJS, improving access control and reducing unauthorized access attempts, enhancing overall security; - Optimized Cytoscape.js for large-scale data visualization, reducing loading times by ~30% and improving rendering efficiency for datasets with thousands of nodes; - Dockerized backend services, using NestJS modules to create a structured API architecture, simplifying CI/CD pipelines and enabling smoother multi-platform deployments.

Poolman is a Ukrainian company specializing in the production and wholesale distribution of professional pool and spa care products. Their offerings encompass a range of solutions designed for water purification, disinfection, and maintenance, catering to various types of pools and spas. The product line includes treatments for pH control, oxygen-based and chlorine-based water disinfection, algae removal, water clarification, and other auxiliary agents. Emphasizing innovation and environmental safety, Poolman aims to provide effective solutions that ensure optimal water quality. Their in-house production facilities and dedicated team of water treatment experts enable them to develop products that meet and often exceed customer expectations.

- Built cross-browser, fully responsive landing pages with Tailwind CSS and Next.js, ensuring seamless UX across devices; - Developed an e-commerce platform for pool cleaning products using Next.js with Contentful CMS, enabling easy product management and dynamic content updates; - Designed and implemented a multi-page blog using React.js and Strapi CMS, integrating dynamic content management and SEO-friendly features.