Backend Engineer focused on reliable services, concurrency, and networking.

I build backend systems in Go and Java, with an emphasis on correctness, observability, and maintainable architecture. I also explore lower-level networking and systems programming in C++.

📍 Poland

Developing PacketLens — a Linux packet sniffer that captures live network traffic and decodes Ethernet, IPv4, TCP, and UDP headers.

Backend

Infrastructure and observability

Systems and tooling

Runtime-configurable reverse proxy and edge gateway.

• Host- and path-based routing with health-aware load balancing
• Rate limiting, retries, active health checks, and trusted proxy handling
• Atomic runtime configuration snapshots and authenticated HTTP/gRPC control plane
• Prometheus metrics, Grafana dashboard, and Docker Compose environment
• Automated tests, static analysis, and race detection

Go HTTP gRPC Concurrency Prometheus Grafana Docker

Transactional ecommerce backend built with Spring Boot.

• JWT authentication and role-based access control
• Product catalog, shopping cart, orders, and inventory reservations
• Stock restoration on cancellation and idempotent mock payments
• PostgreSQL migrations with Flyway
• Integration tests using JUnit and Testcontainers
• OpenAPI documentation with Swagger UI

Java 21 Spring Boot PostgreSQL Flyway Testcontainers Docker

Command-line packet sniffer for Linux.

• Captures live traffic using raw sockets and reads classic PCAP files
• Decodes Ethernet II, IPv4, TCP, and UDP headers
• Built with modern C++17 and CMake
• Tested with Catch2 and synthetic packet data

C++17 Linux Networking Raw sockets CMake Catch2