Łukasz Łepecki

Resume

PDF Markdown

Senior back-end engineer specializing in .NET, API design, and distributed architectures. 16 years building systems that scale and code that lasts. Comfortable owning features end-to-end: from client requirements through architecture to release. Track record of solving systemic problems and creating internal tools that teams actually adopt. Experienced with cloud-native development. Capable across the stack when needed, but backend is my home. I improve systems, not just maintain them.

Skills

Core

  • .NET
  • C#
  • F#

Working Knowledge

  • C++
  • JavaScript
  • TypeScript
  • Node.js
  • React

System Architecture

  • API design
  • Microservices
  • Distributed systems
  • Domain-driven design
  • Event sourcing
  • CQRS

Cloud & Infrastructure

  • Azure
  • AWS
  • GCP
  • RabbitMQ
  • Docker
  • Kubernetes
  • Terraform

Data

  • Microsoft SQL Server
  • PostgreSQL
  • CosmosDB
  • Redis

AI

  • Codex
  • Claude Code
  • Agentic workflows

Languages

  • Polish · C2
  • English · C1

Work History

Senior Back-End Engineer · Tributech

Linz, Austria · Jun 2024 - Present · www.tributech.io

.NET / C#, PostgreSQL, Redis, Docker, Kubernetes, Keycloak, Cerbos

  • Build and maintain APIs enabling external client integrations; own DevOps responsibilities including deployment pipelines and infrastructure
  • Designed a permission-matrix testing system that replaced scattered authorization tests across endpoints - eliminated duplicated code, cut test execution time, and made permission updates trivial to maintain
  • Led R&D initiative evaluating Cerbos for attribute-based access control; delivered working .NET proof-of-concept enabling authorization decisions based on request context, not just user roles

Senior Back-End Engineer · CyberVadis

Warsaw, Poland · Apr 2022 - Jun 2024 · cybervadis.com

.NET / F#, Azure (Function Apps, Service Bus, Key Vault, storage), Microsoft SQL Server, Docker, Terraform

  • Delivered business features end-to-end using Domain-Driven Design; developed and maintained core backend services communicating via messaging infrastructure
  • Built internal Azure Service Bus abstraction library that solved a persistent company-wide problem of messages silently lost between microservices - became the standard for async communication across teams

Senior Back-End Engineer · Ilabo

Warsaw, Poland · Dec 2020 - Apr 2022 · ilabo.com

.NET / C#, Azure, EventFlow, Microsoft SQL Server, CosmosDB, Redis, RabbitMQ, Docker, Kubernetes

  • Developed core microservices for a MES (Manufacturing Execution System) platform; contributed to key architectural decisions shaping the system’s design
  • Owned end-to-end delivery of the platform’s public API - gathered requirements directly with external clients, led technical design, and drove the team through implementation to release

Senior Back-End Engineer · Appfire

Gdansk, Poland · Aug 2019 - Dec 2020 · appfire.com

.NET / C#, Node.js, TypeScript, GCP

  • Developed TFS4JIRA, the company’s flagship product syncing Azure DevOps with Jira
  • Worked directly with clients to gather requirements and shape product direction

Senior Full-Stack Engineer · ABB

Cracow, Poland · Feb 2018 - Aug 2019 · www.abb.com

.NET Core / C#, ASP.NET, React, Azure, Microsoft SQL Server, EF Core

  • Built corporation-wide technical documentation portal - full-stack delivery from backend services to React frontend
  • Optimized for security and performance at enterprise scale

Senior Full-Stack Engineer · KMD

Warsaw, Poland · May 2015 - Feb 2018 · www.kmd.net

.NET / C#, ASP.NET, Angular, Microsoft SQL Server, EF Core

  • Architected and built core backend for a greenfield mobile payment platform serving the Danish market
  • Implemented PSD2-compliant APIs enabling secure third-party access to banking services
  • Built authentication and authorization systems meeting EU regulatory requirements

Back-End Engineer · Canon Ophthalmic Technologies

Wroclaw, Poland · Nov 2014 - Apr 2015 · www.canon-ot.com.pl

.NET / C#, WPF, WCF

  • Developed desktop application for ophthalmic examinations - strict medical device compliance, rigorous validation processes
  • Delivered production-ready software meeting healthcare regulatory standards

Back-End Engineer · Scientific Games

Cracow, Poland · Aug 2013 - Nov 2014 · www.scientificgames.com

.NET / C#, ASP.NET, Microsoft SQL Server, NHibernate

  • Developed web services for government institutions - international project spanning three countries
  • Coordinated across distributed teams and time zones; delivered APIs meeting governmental security requirements

Back-End Engineer · Novomatic Technologies Poland

Cracow, Poland · Jun 2009 - Aug 2013 · novomatic-tech.com

.NET / C#, C++, ASP.NET, WPF, Microsoft SQL Server

  • Progressed from Test Automation Engineer to Back-End Engineer across multiple gaming infrastructure projects
  • Built core systems including cryptographically secure RNG module, real-time telemetry pipeline, and remote software deployment platform
  • Developed ATM integration module with transaction security protocols connecting hardware to banking infrastructure
  • Created automated testing tools and load simulators that expanded QA coverage while reducing manual effort

Education

MSc · Automation and Robotics · AGH University of Science and Technology

Cracow, Poland · Oct 2004 - Jun 2010 · www.agh.edu.pl

Thesis: OCR Neural Network Implementation on an Embedded Device (C++, .NET, embedded)

Certificates

AI_devs 3 Reloaded

AI Devs · Jul 2025 · credsverse.com/credentials/c55c2e6e-7043-4eea-b0fb-f005c6a4d2de

  • Agentic workflows
  • Large language models (LLM)
  • Large language model operations (LLMOps)
  • Vector databases
  • Graph databases

Game Theory

Stanford University · May 2025 · www.coursera.org/account/accomplishments/verify/1Y9GRREZTEC0

  • Mixed-strategy Nash equilibria
  • Alternative solution concepts
  • Extensive-form games
  • Repeated games
  • Bayesian games
  • Coalitional games

Professional Scrum Developer I (PSD I)

Scrum.org · Apr 2024 · www.credly.com/badges/a95f1e0b-b913-4124-96c5-99265c2bdea6

  • Scrum roles, artifacts and events
  • Sprints, sprint goals and increments
  • User stories, acceptance criteria and refinement
  • Estimation and progress tracking (boards, burndown charts)
  • Reviews, retrospectives and continuous improvement

Certified Tester Foundation Level (CTFL)

ISTQB · Jan 2010 · istqb.org

  • Fundamentals of software testing and QA
  • Role of testing in the software development lifecycle
  • Static testing techniques
  • Black-box and white-box test designs
  • Test management, planning, estimation and reporting
  • Defect lifecycle, metrics and communication with stakeholders

Open Source

FriendlyEnvars

github.com/llepecki/friendly-envars

Type-safe environment variable binding for .NET that maps environment variables directly to strongly typed configuration classes with automatic conversion and validation.

Teaching

Guest lecturer at two Polish universities on software design, OOP, design patterns, and agile processes.

  • Warsaw University of Information Technology · Oct 2016 - Jan 2017
  • AGH University of Science and Technology · Oct 2011 - Jan 2012