Giorgos Mitaros
Verified Expert in Engineering
Back-end Engineer and Developer
Athens, Central Athens, Greece
Toptal member since March 7, 2025
Giorgos is a highly skilled back-end engineer with 5+ years of experience in Java, Spring Boot, Kafka, and cloud-native architectures. He specializes in building scalable, high-performance systems and has a strong background in event-driven microservices. Passionate about solving complex challenges, Giorgos delivers clean, efficient code and thrives in dynamic, fast-paced environments.
Portfolio
Experience
- Java - 5 years
- Jira - 5 years
- Spring Boot - 5 years
- RabbitMQ - 5 years
- Kubernetes - 4 years
- Docker - 3 years
- PostgreSQL - 3 years
- Apache Kafka - 2 years
Availability
Preferred Environment
Java, Spring Boot, Apache Kafka, RabbitMQ, Kubernetes, Docker, Slack, PostgreSQL, IntelliJ IDEA, Jira
The most amazing...
...thing I've built is a real-time event processing system that handles 15+ million Kafka messages daily—enabling accurate bet calculations and financial insights.
Work Experience
Senior Software Engineer
OPAP
- Processed high-volume betting data of 6+ million bets daily with Kafka to calculate real-time gross gaming revenue per player, enhancing financial reporting accuracy.
- Implemented new features on communication services for campaigns, handling push notifications, SMS, and Viber messages to over 200,000 customers, increasing campaign effectiveness.
- Orchestrated platform scalability with Kubernetes and integrated Azure services for robust back-end solutions, achieving 99.9% uptime.
- Conducted proof of concept (POC) on Quarkus, exploring performance improvements for Java applications.
- Improved bonus mechanisms in the player account management platform by developing new features using Java, Spring Boot, and Oracle Database, enhancing player engagement and retention.
- Migrated the monolithic application to a microservices architecture, transitioning from WildFly server to Spring Boot microservices, improving scalability and maintainability.
- Developed an event processing service with a team, leveraging RabbitMQ, Azure Functions, and Azure Event Hubs to unify event payloads for downstream processing.
- Implemented real-time analytics using Azure Stream Analytics to generate informational events such as user inactivity after login or deposit behaviors, enabling targeted marketing campaigns and increasing user activity by 25%.
- Integrated with Salesforce and gamification platforms, providing enriched event data to trigger personalized bonuses and gamification tasks, boosting customer engagement.
Application Development Senior Analyst
Accenture
- Led the development of the stock and bond purchasing process digitalization through web banking, increasing online investment transactions.
- Collaborated with business analysts, QAs, and cross-functional teams to deliver high-quality software solutions on time.
- Enhanced database efficiency and query execution speed by optimizing SQL scripts, structuring tables, and adding strategic indexing, improving application responsiveness by 35%.
Application Development Analyst
Accenture
- Maintained automated regression tests and Jenkins pipelines, allowing continuous integration and reducing deployment times by 50%.
- Provided technical estimates for new projects and mentored junior developers in software patterns, Kubernetes, and microservices.
- Developed a multi-business account management system, allowing seamless access to company accounts.
Application Development Associate
Accenture
- Designed and implemented full-stack features for an omnichannel banking platform using Java, Spring Boot, RabbitMQ, and React, improving customer engagement and operational efficiency.
- Ensured software reliability by writing unit and integration tests, enhancing system stability.
- Collaborated with cross-functional teams in an Agile environment to deliver scalable, high-performance banking solutions.
Experience
Real-time Event Processing System for a Betting Platform
The system processed critical user events such as logins, bet placements, and transactions. Using Kafka, RabbitMQ, and Spring Boot, I developed a microservices-based architecture to ensure scalability and fault tolerance.
The solution transformed raw event data into structured payloads, integrated with Azure Event Hub, and provided real-time analytics. This project significantly improved data accuracy and reduced latency in financial reporting, enhancing overall system reliability.
Education
Engineering Diploma in Computer Science and Engineering
University of Ioannina - Ioannina, Greece
Skills
Libraries/APIs
REST APIs, React, Jenkins Pipeline
Tools
RabbitMQ, Slack, IntelliJ IDEA, Jira, Jenkins, WildFly
Languages
Java, Python, SQL
Frameworks
Spring Boot, Spring, Spring Batch, Spring Microservice
Paradigms
Event-driven Architecture, Event-driven Design (EDD), Microservices, Microservices Architecture, Gamification, App Development, Continuous Integration (CI), Unit Testing, Software Testing, Agile
Platforms
Apache Kafka, Azure Event Hubs, Kubernetes, Docker, Azure Functions, Azure, Oracle Database, Salesforce
Storage
PostgreSQL, SQL Server 2019, Redis
Other
API Integration, Distributed Systems, Azure Stream Analytics, Computer Science, Software Engineering, Software Development, Back-end, Back-end Development, Proof of Concept (POC), Quarkus, Full-stack, Full-stack Development, Integration Testing
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