Kristian – React, Typescript, Node.js

An online language learning platform designed to provide an intuitive and user-friendly interface for learners. The product integrates AI-powered features to enhance the learning experience, support personalized practice, and improve language acquisition through interactive and adaptive tools.

• Designed and built an AI-powered language learning platform as a solo developer, initially developed in Laravel/PHP and later migrated to TanStack Start;
• Architected the full-stack application using TanStack Start, PostgreSQL, Redis, BullMQ, Docker, and OpenAI APIs;
• Built background processing pipelines with BullMQ and worker processes to handle video transcription, AI content generation, and other long-running tasks;
• Integrated OpenAI Whisper to transcribe video content and generate dual-language subtitles, enabling learners to study content without existing translations;
• Developed a spaced repetition system for reviewing saved words and phrases, including detailed progress tracking and learning analytics;
• Designed and implemented the database schema, API architecture, deployment infrastructure, and CI/CD pipelines;
• Deployed and maintained the platform on a self-managed VPS using Docker.

A fast-paced e-commerce platform project focused on large-scale modernization and multiple full-stack migrations. The system was initially built on a monolithic e-commerce architecture and progressively transitioned through several tech stacks, moving from Magento to a modern Next.js and Node.js setup, and later evolving into a Remix-based architecture with AWS Lambda-powered backend services. The project involved improving scalability, performance, and developer experience while supporting a high-traffic online retail environment.

• Oversaw four teams (around 15 developers) with direct line management, mentoring, and regular performance reviews;
• Led development teams on the main web application project, combining technical leadership with managerial responsibilities;
• Set and upheld high coding standards with thorough documentation, fostering a team culture focused on code quality through peer reviews and consistent use of custom, strict ESLint and Prettier configurations;
• Continuously looked for ways to make the team more efficient, such as merging or rearranging teams, reducing any unnecessary processes, reducing build times, and coordinating QA work to save time and effort;
• Delivered a white-labelled Next.js application supporting multiple brands, each with its own design system via Storybook and Chromatic;
• Revamped the testing strategy with major performance optimizations to Jest, Vitest, and React Testing Library, achieving sub-two-minute runs for 7,000+ tests, and incorporated MSW for reliable API mocking;
• Collaborated with design teams to build scalable, accessible design systems, using Tailwind CSS, SCSS, and Radix UI to maintain consistent design and improve site accessibility;
• Ensured high site performance, achieving passing Core Web Vitals scores through React optimizations and effective caching strategies, even with Google Tag Manager injecting various third-party scripts;
• Handled security fixes from HackerOne, ensured successful pen tests and secure JWT auth, and managed monitoring and on-call duties using Sentry, Dynatrace, and PagerDuty to maintain system reliability;
• Ran A/B and multivariate tests using Webtrends to optimize conversion funnels and improve user experience;
• Oversaw the migration from a legacy Magento 1 (PHP) site to Next.js with a Node.js API gateway connecting to AWS microservices;
• Architected the white-label structure to scale efficiently while allowing completely custom themes per brand, while keeping it maintainable and making sure the site performance is top-notch;
• Migrated from Contentful to Strapi, bringing in over £100k in yearly cost savings.

FrogOS is a learning management system for schools and businesses. It is a web frontend that offers many different applications within itself.

• Worked on a large legacy LAMP-based learning management system used by schools.
• Built the Markbook application as the sole frontend developer, working closely with designers and stakeholders throughout development.
• Developed and optimised complex data-heavy interfaces, with a focus on maintaining performance in Internet Explorer.
• Worked on the Courses platform, extending the product to support enterprise e-learning use cases.
• Rebuilt the platform's WYSIWYG page builder.
• Developed features including course creation, event management, and management dashboards.
• Contributed to technical planning and discussions around architectural improvements within the codebase.
• Worked in a Scrum team alongside developers, designers, UX, and stakeholders.
• Built frontend features using JavaScript, jQuery, PHP, MySQL, HTML, and CSS.

A web-based learning management system (LMS) designed for educational institutions and businesses. The platform provides a unified frontend that hosts multiple integrated applications, enabling users to manage learning content, training programs, and organizational workflows within a single system.

• Contributed to a large legacy LAMP-based learning management system used by schools, focusing on maintaining and evolving an enterprise codebase;
• Built the Markbook application as the sole frontend developer, collaborating closely with designers and stakeholders throughout development;
• Developed and optimized complex, data-heavy interfaces with a strong focus on performance and cross-browser compatibility, including Internet Explorer support;
• Extended the Courses platform to support enterprise e-learning use cases and broader organizational needs;
• Rebuilt and improved the platform’s WYSIWYG page builder to enhance usability and content creation workflows;
• Delivered features including course creation, event management, and administrative dashboards for end users and administrators;
• Participated in technical planning and architectural discussions to improve system structure and maintainability;
• Worked within a Scrum team alongside developers, designers, UX specialists, and stakeholders.