MateuszSkrzypczyk

New business domain - team of 4 developers

• Leading a 4-person development team in a new business domain: owning delivery of business goals, team growth, code review and work planning
• Conducted over 100 technical interviews for Senior Java Developer and QA Tester roles across Empik teams
• Designing and rolling out onboarding processes for new developers, raising the team's operational efficiency
• Working closely with business stakeholders and Product Owners to translate domain requirements into microservice architecture and technical specifications
• Introducing AI-assisted software development: coaching developers on Claude Code (CLI) and MCP tool integrations to automate repetitive engineering work

empik.com - Customer domain (Auth / Identity)

• High traffic & scalability: developed and maintained the core Customer domain (Auth/Identity) serving up to several hundred requests per second during critical business events
• Microservices architecture: owned and maintained an ecosystem of ~20 microservices (Java 17/21, Spring Boot, Kotlin)
• Greenfield design: single-handedly designed and shipped dedicated microservices for user account discount coupons and asynchronous notification delivery (e-mail / SMS)
• Security & auth: modernized the legacy user session system on empik.com into a JWT based architecture, implemented post-audit recommendations and fixed vulnerabilities including XSS
• Performance & cost optimization: eliminated N+1 query problems in PostgreSQL/Oracle, significantly reducing API response times, and cut costs of third-party integrations (SMS gateways, Cloudflare, Synerise)
• Async communication: designed and implemented cross-domain integrations based on REST API, Apache Kafka and ActiveMQ
• Observability & on-call: served production on-call duty, monitoring application health and resolving incidents with Grafana, Prometheus and Kibana
• Frontend support: delivered UI tasks as needed using React, TypeScript and JavaScript

Automotive backend platform & SITA aviation connectivity

• Automotive sector: designed and developed new modules and integrations for a backend platform connected to vehicles of leading car brands
• Aviation sector (SITA): built a solution providing and managing internet access for airline passengers
• Architecture & documentation: prepared technical documentation and implemented architectural solutions in a monolithic environment

IoT platform modernization

• Modernization & refactoring: rebuilt legacy systems from the ThingWorx (IoT) platform onto a modern microservice based stack
• IoT integrations: extended existing system functionality and implemented new integrations for Internet of Things devices

Internal social media application

• End-to-end application development: designed and shipped to production an internal social media app for company communication and announcements
• Architecture design: single-handedly designed the architecture of the entire backend system and prepared the presentation layer