kassio.net Software Engineer
Experienced backend software engineer focused on building robust, scalable, and secure enterprise systems. Skilled in designing efficient APIs, optimizing data workflows, and delivering high-performance solutions for web, mobile, and cloud platforms.
About Me
I'm a backend engineer with over 10 years of experience building high-performance, scalable systems for enterprise applications. My expertise lies in designing resilient architectures that can handle millions of requests while maintaining optimal performance and security.
Throughout my career, I've worked with a variety of technologies including .NET, Java and Python. I'm passionate about clean code, architecture, and infrastructure.
When I'm not coding for work, you might find me coding for fun, writing technical articles on my blog about backend development, distributed systems, and cloud architecture.
Database Design
Optimizing data models and queries for performance and scalability
API Development
Creating robust REST APIs with extensive documentation
Cloud Infrastructure
Designing and implementing cloud-native applications
Security
Implementing robust security measures and best practices
Technical Skills
Languages
- • C#
- • Java
- • Python
- • JavaScript
- • SQL
Frameworks
- • ASP.NET Core
- • Spring Boot
- • DevExpress ExpressApp (XAF)
- • Express.js
Databases
- • SQL Server, Oracle
- • PostgreSQL, MySQL
- • SQLite
- • MongoDB
- • Redis
Tools & Cloud
- • Docker, Podman, Containerd, Kubernetes
- • Bash, PowerShell
- • Azure, AWS, GCP
- • GitLab, Azure DevOps, GitHub Actions, TeamCity
- • Terraform, Ansible
Work Experience
Senior Backend Engineer
Grand Parade part of William Hill
Development and modernization of core microservices by implementing regulatory requirements through scalable, maintainable designs. Migrated critical services from Windows to Linux and from .NET Framework to .NET 6, significantly enhancing performance and maintainability.
- Implemented new regulatory requirements in an extensible and maintainable design.
- Maintained and improved existing core microservices, ensuring quality and best practices.
- Migrated services from Windows to Linux, improving performance and reducing costs.
- Implemented containerization and orchestration strategies using Docker and Compose.
- Improved microservices resilience and performance by implementing several techniches like circuit breaker, retry, timeout and connection pooling.
- Migrated several microservices from .NET Framework 4 to .NET 6, improving performance and maintainability.
- Migrated several CI/CD pipelines from TeamCity + BitBucket to GitLab.
Software Developer
Luxoft
Investment banking project for risk analytics department.
- Improved configuration management and deployment for job schedulers.
- Project for MongoDb initialization with several business documents.
- Implemented non-functional analysis of the backend applications generating reports with various performance indicators like computing time, waiting time, database queries, etc.
- CI/CD platform migration from GitHub/TeamCity to GitLab
Software Developer
EPAM Systems
Maintained full stack service for internal users.
- Improved user interface giving better feedback to the user.
- Optimized database lookups resulting beter performance and user experience.
Software Developer
Vsoft Tecnologia
Full-stack developer with focus on backend services and API integrations for B2B SaaS products.
- Implemented integration with Azure Blob Storage for image storage and retrieval.
- Implemented a billing system enabling credit card payments, integrating with external payment gateways.
- Implemented Windows Desktop facial image capture following ICAO standards.
- Implemented improvements in the backend SQL Server and Oracle databases queries, resulting in better performance.
- Implemented hardware integration with fingerprint readers, cameras and signpads.
- Implemented standalone Windows Desktop application for synchronizing monitoring data.
Certifications
Certified Kubernetes Administrator (CKA)
Issued by: The Linux Foundation
Date: Sep 2024
Demonstrates proficiency in Application Lifecycle Management, Installation, Configuration & Validation, Core Concepts, Networking, Scheduling, Security, Cluster Maintenance, Logging / Monitoring, Storage, and Troubleshooting.
Certified Kubernetes Application Developer (CKAD)
Issued by: The Linux Foundation
Date: Feb 2024
Demonstrates knowledge in Core Concepts, Configuration, Multi-Container Pods, Observability, Pod Design, Services & Networking, State Persistence.
AWS Certified Cloud Practitioner
Issued by: Amazon Web Services
Date: Jan 2022
Demonstrates cloud fluency and foundational AWS knowledge. Able to identify essential AWS services necessary to set up AWS-focused projects.
Microsoft Certified: Azure Developer Associate
Issued by: Microsoft
Date: Oct 2021
Demonstrates the ability to design, build, test, and maintain cloud applications and services on Microsoft Azure.
Linux Essentials Certification
Issued by: Linux Professional Institute (LPI)
Date: Dec 2022
Demonstrates the ability to design, build, test, and maintain cloud applications and services on Microsoft Azure.
API Security Fundamentals
Issued by: APISec University
Date: Feb 2024
real-world API breaches, the OWASP API Security Top 10, the 3 Pillars of API Security (governance, testing and monitoring), and the application security technology landscape.
Get In Touch
I'm always open to discussing new projects, opportunities in backend development, or tech challenges. Feel free to connect with me through any of the platforms below.
Location
Kraków, Poland