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Hi, I’m Stefanos Psyllas, a software engineer specializing in backend development with nearly 3 years of hands-on experience. I enjoy building reliable services and scalable systems, particularly with Java and Spring Boot, and I’m comfortable tackling complex challenges in production environments. I focus on delivering end-to-end backend solutions, collaborating closely with product and DevOps teams, and continuously improving code quality through test-driven development and CI/CD practices. I’m always eager to learn and apply new technologies to real-world problems, especially in the realm of distributed systems and microservices.…Hi, I’m Stefanos Psyllas, a software engineer specializing in backend development with nearly 3 years of hands-on experience. I enjoy building reliable services and scalable systems, particularly with Java and Spring Boot, and I’m comfortable tackling complex challenges in production environments. I focus on delivering end-to-end backend solutions, collaborating closely with product and DevOps teams, and continuously improving code quality through test-driven development and CI/CD practices. I’m always eager to learn and apply new technologies to real-world problems, especially in the realm of distributed systems and microservices.

Stefanos Psyllas

Back-End Developer, Full Stack Developer, Web Developer, +2

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Hi, I’m Stefanos Psyllas, a software engineer specializing in backend development with nearly 3 years of hands-on experience. I enjoy building reliable services and scalable systems, particularly with Java and Spring Boot, and I’m comfortable tackling complex challenges in production environments. I focus on delivering end-to-end backend solutions, collaborating closely with product and DevOps teams, and continuously improving code quality through test-driven development and CI/CD practices. I’m always eager to learn and apply new technologies to real-world problems, especially in the realm of distributed systems and microservices.…Hi, I’m Stefanos Psyllas, a software engineer specializing in backend development with nearly 3 years of hands-on experience. I enjoy building reliable services and scalable systems, particularly with Java and Spring Boot, and I’m comfortable tackling complex challenges in production environments. I focus on delivering end-to-end backend solutions, collaborating closely with product and DevOps teams, and continuously improving code quality through test-driven development and CI/CD practices. I’m always eager to learn and apply new technologies to real-world problems, especially in the realm of distributed systems and microservices.

Available to hire

Hi, I’m Stefanos Psyllas, a software engineer specializing in backend development with nearly 3 years of hands-on experience. I enjoy building reliable services and scalable systems, particularly with Java and Spring Boot, and I’m comfortable tackling complex challenges in production environments.

I focus on delivering end-to-end backend solutions, collaborating closely with product and DevOps teams, and continuously improving code quality through test-driven development and CI/CD practices. I’m always eager to learn and apply new technologies to real-world problems, especially in the realm of distributed systems and microservices.

Skills

Java

Docker

MySQL

Experience Level

Java

Expert

Docker

Expert

MySQL

Intermediate

Language

Greek, Modern

Fluent

English

Advanced

Work Experience

Software Engineer at Cogn ity

November 1, 2025 - Present

Engineered Java/Spring Boot microservices for international B2G welfare and taxation systems, managing end-to-end feature delivery and client change requests. Orchestrated complex business logic with Drools and Camunda BPMN, and utilized Liquibase to manage database schema evolutions in Oracle SQL environments. Maintained high system stability through comprehensive unit testing and refactoring within an Agile/DevOps workflow using Azure DevOps and GitLab.

Software Engineer at Net Company

October 1, 2024 - October 31, 2025

Engineered Java/Spring Boot microservices for a high-traffic international B2G welfare and taxation platform, delivering end-to-end features and handling client change requests. Implemented scalable backend logic using Kafka, Drools, and Camunda; orchestrated CI/CD with GitLab/Jenkins; ensured database evolution in Oracle SQL environments with Liquibase.

Backend Developer at Beyond Innovation

October 1, 2023 - September 30, 2024

Engineered backend customizations for a dedicated-insta SaaS platform, developing client-specific modules and functionality tailored to public institutional (B2G) requirements. Maintained consistent version control and deployments across environments to support rapid feature delivery.

Technical Support Engineer at Upstream

September 1, 2022 - June 30, 2023

Delivered Level 1 technical support and incident resolution for global infrastructure using Tableau and Grafana to monitor system health. Conducted deep-dive investigations and troubleshooting using DB Beaver, Postman, and PuTTY to maintain system availability.