Sebastian – React, React Native, Node.js

Developed a fully customized e-commerce solution for a company specializing in luxury massage chairs, handling the entire engineering process from scratch while collaborating closely with the CEO in a self-managed role.

• Architected and implemented a scalable and high-performance platform tailored for high-end clientele.
• Designed and developed a seamless user experience, optimizing product browsing and purchasing flows.
• Integrated payment solutions and a secure backend to ensure a smooth transaction experience.
• Led technical decision-making, ensuring best practices in development, security, and performance.
• Self-managed workflow, communicating directly with the CEO to align business goals with technical execution.

The mobile application provides users with a user-friendly interface to effortlessly check into events, enhancing the overall experience. Engineered a highly optimized map solution capable of rendering millions of markers to represent user check-ins in real time. The system not only ensures exceptional performance but also provides an interactive and visually engaging map experience.

• Utilized GeoJSON layers to efficiently manage event markers and user check-ins.
• Implemented real-time animations to enhance the interactive experience when check-ins occur.
• Focused on research, architecture, and optimization, ensuring scalability and smooth coordination across the team.
• Streamlined the check-in process, ensuring smooth and quick interactions via geolocation and QR scanning.
• Integrated AI-generated avatars, dynamically created based on user preferences with submasks.
• Enhanced the UI/UX with an intuitive and responsive design, making event participation more engaging.

Developed and deployed secure, tech-enabled bicycle parking solutions to promote sustainable urban mobility across multiple cities in Europe.

• Increased bicycle parking availability by 3x through the deployment of smart, modular shelters across multiple cities.
• Reduced bike theft incidents by 40% by integrating secure locking mechanisms and real-time monitoring systems.
• Enhanced user convenience with a mobile application for seamless access and a management portal for parking administration.
• Optimized urban mobility infrastructure by collaborating with local governments and sustainability initiatives.

Companies organizing team off-sites struggled with high travel costs, complex logistics, and unpredictable pricing. They needed a tool to estimate and compare travel expenses efficiently, saving time and budget while accommodating diverse team preferences.

• Reduced trip planning time by 90% by building an automated cost estimation platform that compares flights and hotels for teams of up to 3,000 people.
• Saved companies thousands in travel costs by integrating real-time flight and hotel pricing, optimizing for price, time, and comfort.
• Increased decision-making efficiency by developing shareable reports and improving financial transparency for leadership teams.

An on-demand mobile app that would allow users to book their modular offices throughout the city.

• Designed the whole architecture for both the backend (node.js) and front-end (react-native).
• Created multiple integrations with different providers, including hardware (smart locks provided by SaltoKS).
• Wrote unit tests with Jest.
• Make the app cross-platform for iOS and Android.
• Co-designed with the designer in Figma and extracted components into a design system.

An app that would aggregate all sensor data from the modular workplace suite - Phonebooths and Meeting Room models into an analytic dashboard.

• Architected both frontend (Next.js) and backend (Ruby on Rails / Node.js) applications.
• Worked on an online service built on top of the embedded hardware to get insight into the product usage post-delivery.
• Increased new sales opportunities by 40% by providing a custom analytics dashboard to the customers and the sales team.
• Worked on useful insight about users' behavior and product usage in a human-readable format.
• Increased business valuation by a factor of 10 by architecting and implementing an Internet of Things (IoT) system.
• Developed an online service for order tracking and analytics.

Worked as a contractor for an online fashion retailer in a team of more than 50 engineers. Improvement of the existing application’s checkout flow for the customers.

• Sped up the checkout process by 23% and reduced friction by rewriting the whole checkout flow codebase with a faster and more efficient one.

An implementation of an app that would allow the user to control his money flow through budget creation and managing goals by investing in different assets.

• Architected the whole backend (Ruby on Rails / Node.js).
• Reached over 90% test coverage of backend functionalities.
• Reduced development time by 2 months by stepping up into the technical lead role and efficiently prioritizing clients’ needs for my team.
• Decreased the time spent on investments and budgeting processes by 70% by designing and implementing a custom architecture to ensure high scalability and availability.

An online editor meant to be used by specialized translators and have multi-language support.

• Worked on an online editor meant to be used by specialized translators and have multi-language support.
• Maximized the editor's speed by 25% by performing intensive refactoring and updates over the old legacy codebase.
• Optimized development speed by 40% by changing the whole flow of the project.
• Increased the overall productivity of translators by 30% by providing instant visual feedback by designing a separate application that communicated 2-way with the editor and renders the translated document in real-time.
• Increased internship hiring rate by 50% by successfully mentoring 4 interns by having individual pair programming sessions and teaching them best practices.
• Coached the interns on principles of client-server communication and basic front-end and back-end architecture.

The goal was to accelerate the process of drug acceptance in the pharmaceutical market and needed a solution to replace the painfully slow process that resulted in money loss.

• Accelerated the process of drug acceptance in the pharmaceutical market.
• Reduced the drug acceptance time by months, even years, by segregating the business flow into three steps by conducting in-depth research of the market.
• Built a suite of apps to handle the needs of each stage of the process efficiently.
• Increased the probability of extending the pharmaceutical app suite by 100% by assuming responsibility and implementing a Proof of Concept.
• Designed a custom reconciliation algorithm to allow medical users to upload, review easily, and control medical documents.