Jaroslaw Slabik

Jaroslaw Slabik — C++ Software Engineer

Expertise in Back-End Web (8.5 yr.), Full Stack Web (3.5 yr.).

Last verified on September 20, 2025

Core Skills

C/C++/C#

8 yr.

Python

2 yr.

Boost

Qt/C++

Bio Summary

Experienced C++ Software Engineer with 8+ years in designing high-performance, distributed, and multithreaded systems. Specialized in backend development with Kafka and SQL. Increased throughput by 20% and reduced memory usage by 10% in mission-critical systems for finance and healthcare. Passionate about concurrency challenges and building reliable distributed architectures.

Technical Skills

Programming Languages	JavaScript, Python
Android Libraries and Tools	Android APIs
C++ Frameworks	Boost, Qt/C++
C++ Libraries and Tools	C/C++/C#
UI Frameworks, Libraries, and Browsers	CSS, HTML
Databases & Management Systems / ORM	AWS ElasticSearch, HDFS, MongoDB, PostgreSQL, SQLite
Amazon Web Services	AWS ElasticSearch
Azure Cloud Services	Azure Service Bus
SDK / API and Integrations	Android APIs
Methodologies, Paradigms and Patterns	Architecture and Design Patterns, Scrum
QA, Test Automation, Security	Code Review, e2e testing
Virtualization, Containers and Orchestration	Docker
Version Control	Git
Operating Systems	iOS, Linux, macOS, Windows
Deployment, CI/CD & Administration	Jenkins
Other Technical Skills	Multithread, Qml

Work Experience

Senior Software Engineer (Freelance), Optimization and Enhancement of Multithreaded Systems

Duration: Jun 2023 – Present

Summary: Optimized multithreaded components, introduced unit and end-to-end testing, migrated to Docker, and replaced proprietary protocol with Apache Avro for better interoperability

Responsibilities: Optimizing data throughput and memory usage, promoting code quality and testing, maintaining streamlined component management

Software Engineer (Freelance), Legacy Application Integration

Duration: Nov 2021 – May 2023

Summary: Merged three legacy applications into a unified platform, ensured continuous delivery of features, and improved team productivity through mentoring

Responsibilities: Merging legacy applications, maintaining and enhancing software, defect identification and resolution, code review, and junior developer mentorship

Technologies: C++ | Qt | QML | MQTT | Git | Linux | Android | iOS | macOS

Full Stack Software Engineer (Contract), Healthcare Scheduling and Payment Module

Duration: Mar 2021 – Present

Summary: Redesigned doctors’ scheduling module, implemented online payments, and led defect resolution with the QA team to optimize performance and usability

Responsibilities: Redesigning scheduling module, implementing payments, collaborating with QA, code review, and mentoring

Full Stack Software Engineer (Freelance), Large-scale Event Management System

Duration: Dec 2019 – Oct 2021

Summary: Developed a distributed online system for event management, optimized high-volume SQL transactions, and maintained event management applications

Responsibilities: Building distributed online event management system, optimizing SQL queries, translating business requirements to technical solutions, application maintenance

Software Developer, Mobile Payment Integration

Duration: Nov 2019 – Feb 2021

Summary: Integrated BLIK mobile payments, maintained applications, resolved legacy code issues, and contributed to Agile sprint deliverables

Responsibilities: Adding mobile payment support, maintaining and updating applications, resolving critical bugs, Agile sprint participation

Software Developer, Medical Pump Firmware Update Mechanism

Duration: Jan 2017 – Oct 2019

Summary: Developed a WiFi-based firmware update mechanism for medical pumps, ensured regulatory compliance, and participated in cross-functional team solutions

Responsibilities: Developing firmware update mechanism, ongoing maintenance and support of medical software, cross-functional team collaboration

Education

Master of Science: Information Technology
Polish-Japanese Academy of Information Technology - Warsaw, Poland
Bachelor of Science: Information Technology
Warsaw School of Computer Science - Warsaw, Poland

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