Jędrzej Siewierski

Responsible for the company’s tech vision, system architecture, and building products from the ground up. Combines deep engineering expertise with a strong business mindset. Drives product strategy, automation, and ensures technology delivers real value for clients and the company.

Day 1 at Damisa: empty repo, ambitious deck, a handful of people. Day ~300: a live cross-border payments rail moving real money, ~30 people on board, £2.25M pre-seed closed (Fuel Ventures), licences in PL & AU, an APAC settlement partnership with dLocal announced. I was one of the founding engineers -> helped recruit the team, shipped the MVP, and owned chunks of the platform end-to-end: payment workflows on Temporal, custody integrations (Fireblocks, DFNS), KYC/KYT (Sumsub, Auth0), settlement rails (Yellowcard, Hercle, dLocal), the Formance ledger, observability on New Relic, the E2E pipeline, and AWS/EKS infra in Terraform. Currently very deep into AI-augmented engineering, heavy Claude Code + Cursor user, writing custom skills, agents and hooks that bake LLMs into real engineering pipelines instead of one-off prompts.

LoftyWorks is an integrated SaaS platform for real estate management, combining property operations, marketing, CRM, and finance in a unified interface. As part of a global team, I was responsible for maintaining and refactoring over 200 AWS Lambda functions in a complex distribiuted architecture. I focused on improving system stability, streamlining deployment processes, and optimizing workflow automation. Key contributions: * Migrated the engineering team from Git Flow to trunk-based development, improving CI/CD performance and simplifying code collaboration. * Integrated Microsoft Entra to enhance internal app security and streamline access control. * Collaborated closely with leads to identify bottlenecks and implement architectural improvements. * Removed legacy code, improved documentation, and established clearer development standards. * My work resulted in higher system reliability, faster deployments, and better overall team efficiency.

Health Folder is a next-generation MedTech platform redefining how patients and doctors interact with medical data. Available on mobile and web, it allows patients to store and manage their health records in one place and enables healthcare providers to access real-time, AI-enhanced insights for better clinical decisions. Key contributions: Designed and implemented backend architecture to ensure scalability, data security, and high performance in a regulated environment. Refactored and optimized core logic across AWS Lambda functions, improving response times and infrastructure efficiency. Integrated complex authentication flows including OAuth, OpenID, and MFA to ensure compliance and user safety. Collaborated with frontend and design teams to maintain a seamless cross-platform experience. Conducted A/B testing and applied analytics to improve user engagement and retention. Balanced rapid development with system stability in a fast-moving startup environment. Tech stack: Node.js, TypeScript, AWS (Lambda, EC2, S3), EKS (Kubernetes), Terraform, Docker, GitHub Actions, Jest, Prometheus Tools: Jira, Confluence, Miro, Slack

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I led the backend development for the User Profile Dashboard Hub, a scalable user account platform serving over 300,000 daily active users. My focus was on system stability, security, and clean architecture. Key responsibilities and achievements: Designed and maintained a high-load Node.js backend, gradually refactoring the legacy Express system into a modular architecture based on Inversion of Control Containers (IoCC). Implemented OpenID integration and Multi-Factor Authentication (MFA) to strengthen security and streamline user access across Schibsted services. Introduced Agile and Scrum methodologies to the team, standardized documentation practices, and improved task planning with story points and estimation sessions. Built multi-region CI/CD pipelines for country-specific environments using Terraform, AWS, Spinnaker, and Travis CI, enabling smooth and automated deployments. Mentored new developers, promoted clean code principles, and established best practices for backend architecture and testing. Collaborated closely with product, business, and frontend teams to align priorities, unblock workflows, and ensure fast and efficient iteration. Maintained a strong focus on code quality, including pull request reviews, writing unit/integration tests, and ensuring long-term maintainability. Throughout the project, I worked to improve the development process, strengthen backend reliability, and ensure seamless collaboration across departments — all while keeping user experience and performance at the core.

At Energy Lab, I worked on developing and maintaining a backend engine built on a microservices architecture. The project supports the company's mission to help organizations build a long-term health policy for their employees promoting both physical and mental well-being. Key responsibilities and achievements: Designed and maintained scalable microservices using Node.js, TypeScript, and gRPC, deployed in a Kubernetes environment on Azure Cloud. Implemented GraphQL APIs and handled data persistence across MongoDB and SQL systems. Developed asynchronous service communication with RabbitMQ and caching strategies using Redis. Ensured high test coverage using Mocha, Chai, and Sinon, improving test reliability and regression safety. Applied InversifyJS for dependency injection to maintain clean, modular code across services. Worked with Bitbucket for source control and coordinated across distributed teams following Agile practices. Supported containerized deployment flows with Docker and Docker Compose, optimizing local development and production parity. My contribution helped maintain the performance and reliability of a platform used by organizations focused on building healthier workforces through technology.

At Energy Lab Belgium, I contributed to the development of letsmove.com, an e-commerce platform built on the VueStorefront framework, designed to promote a healthy and active lifestyle. The platform offers high-quality products, services, and sports events to customers who care about wellness and performance. Key responsibilities and achievements: Developed modern, responsive e-commerce interfaces using Vue.js, VueStorefront, Vuex, and SASS, with a focus on user experience and performance. Collaborated with backend teams using Express.js and Node.js, supporting API-driven integration with Magento 2^ and Elasticsearch for fast and reliable product search. Maintained code quality through unit and integration tests with Mocha, Chai, and Sinon. Worked in a Scrum-based Agile team, using Bitbucket, Jira, and Azure Cloud for collaboration and deployment. Contributed to improving development workflow, component reusability, and frontend architecture scalability. Tech Stack: Frontend: TypeScript, JavaScript, Vue.js, Vuex, VueStorefront, SASS Backend: Node.js, Express.js E-commerce: Magento 2, Elasticsearch Testing: Mocha, Chai, Sinon Cloud & DevOps: Azure Cloud, Bitbucket Methodologies & Tools: Scrum, Jira, CI/CD tools My work helped deliver a fast, stable, and engaging platform that empowers customers to pursue a healthy and sporty lifestyle through a seamless online shopping experience.

At Snabel, I developed web and desktop applications using Vue.js and Electron.js, contributing to projects across charity, retail, and mobility sectors. Key responsibilities and achievements: Built responsive web and desktop applications with Vue.js and Electron.js, ensuring smooth UX and performance across platforms. Developed a charity donation platform for a church, including secure payment integration with POLCARD for seamless transactions. Maintained and extended a high-traffic media playback system used in shopping centers across Poland, improving stability and adding new features. Created a Content Management System (CMS) for an electric vehicle mobile app, with a focus on user administration and efficient content handling. Reviewed teammates' code and promoted clean code standards, helping foster a consistent and maintainable codebase. Participated in full-stack development using Python 3 and MongoDB, with strong collaboration across the team. Tech Stack: Frontend: Vue.js, Vuex, HTML5, CSS3, SASS Desktop: Electron.js Backend: Python 3, Node.js Database: MongoDB Integrations: POLCARD (secure payment processing) Code quality: Code reviews, mentoring, clean code best practices

I was responsible for managing and updating English-language technical data for high-profile automotive projects, including Tata Motors and Jaguar Land Rover. Key responsibilities: * Analyzed and maintained technical documentation and part data in MySQL, ensuring accurate and up-to-date records for ongoing Jaguar Land Rover initiatives. * Supported internal communication tools (intranet) and applications related to office productivity and data management. * Collaborated with a global team in a US-based international work environment, ensuring timely delivery and quality assurance. * Ensured information security and compliance with internal data protection procedures in accordance with ISO standards. * Acted as the point of contact for the latest project data, enabling effective knowledge sharing across teams.

• knowledge of CAD 2D, 3D programs, ie SolidWorks (very good) / Inventor (good) / Catia (basic) / AutoCad (Primary) • basic knowledge about ladder programming for industral controlers • knowledge of MS Office package • knowledge about MathCad and Finite Element Methods • knowladge about basic of programming in C++, Java, G-Code(CNC machines) • knowledge of issues from analytical mechanics, strength of elements machines, thermodynamics, electrotechnics • very good knowledge of technical drawing with regard to diagrams electric and pneumatic / hydraulic • handling for all types of power tools • ease in establishing new contacts, ability to work in a team

This educational path focuses on creating a programmer-manager who is not only able to solve complex technological problems, but also efficiently manage large teams of programmers, cooperate on multi-team programming projects and work in the field of modern IT project management methods. Graduates will be able to effectively coordinate the activities of programming teams and effectively implement complex programming projects. Additionally, the specialization focuses on the security of computer systems in software production. The graduate will receive specialist and in-depth knowledge in the field of secure coding and secure application development and how to enhance Software Application with newest Machine Learning methods with modern Cloud Base solutions. Key Skills: * Advanced Software Engineering Methods * System modeling and simulation * Security of computer systems in software production * Agile IT project management methods * Software engineering and software production

9-month intensive programming course using front and back-end issues (720 hours). During my studies, I got acquainted with good practices and conventions of creating websites and web applications. During the course, I realized many projects from scratch, some of them include: - building responsive websites based on a graphic template; - Kanban board, supporting drag & drop and working back-end (MERN stack); - chatroom based on React I Express; - PWA online shoe store - based on React, React Router and Redux; Some of the Bootcamp elements were getting to know and time to work in the Scrum methodology - a monthly group project - using JIRA software. Technologies used: HTML5, CSS, RWD, Bootstrap, SASS / SCSS, Git, AJAX, JS ES6, Node, React, Redux, Express, MongoDB, MER, JIRA, Kanban.