Greece
Senior Software Engineer & Team Lead
Marios Mantratzis
Building backend-heavy, cloud-native software systems. Specializing in distributed architectures, secure API platforms, and high-availability microservices at scale.
JavaSpring BootAzureKubernetesDistributed SystemsMicroservicesEvent-Driven Architecture
About.
Senior Software Engineer and Team Lead with 16+ years of engineering experience and 8+ years of professional work experience building backend-heavy, cloud-native software systems across enterprise and multi-service environments.
Core expertise in Java, Spring Boot, distributed systems, event-driven architectures, secure API platforms, and microservices, with strong hands-on experience in Azure, Kubernetes, Docker, and full-stack delivery with Angular and React when end-to-end ownership is needed.
Proven track record in leading engineering efforts across backend, cloud, and full-stack initiatives—contributing to system design, API security, DevOps practices, performance optimization, mentoring, and code reviews. Delivered and supported large-scale systems involving 10+ production projects.
Core Expertise.
Technology experience matrix spanning backend, cloud infrastructure, distributed systems, and full-stack delivery.
Backend Engineering
Java16 yr total8 yr workSpring Boot9 yr total8 yr workREST APIs11 yr total8 yr workNode.js3 yrSOAP2 yr total1 yr workPHP3 yr total6 mo workPython3 yr total2 mo work
Distributed Systems
Microservices8 yrEvent-Driven Architecture6 yrKafka2 yrRabbitMQ2 yrAzure Service Bus2 yrAzure Event Hub2 yr
Cloud & Infrastructure
Microsoft Azure2 yrAWS2 yrAWS EKS1 monon-workKubernetes3 yrDocker7 yr
Databases
PostgreSQL4 yrAzure Cosmos DB2 yrOracle3 yrMongoDB2 yrRedis3 yrAurora MySQL2 yrMariaDB2 yrMySQL2 yrnon-workDynamoDB3 mo
Testing
JUnit8 yrJMeter4 yrSelenium2 yrCucumber1 yrGherkin1 yr
DevOps
Jenkins5 yrBicep IaC2 yrAWS SAM IaC2 yrAzure DevOps pipelines2 yrArgoCD1 yrAWS CDK IaC1 yrNexus OSS1 yrHelm charts3 yr
Security & Identity
OAuth24 yrOpenID Connect6 yrJWT6 yrMicrosoft Entra ID2 yrKeycloak3 yr total2 yr workmTLS (Istio, Linkerd)6 moAWS Cognito2 yrSAML3 mo
Frontend & Mobile
JavaScript / TypeScript16 yr total8 yr workAngular7 yr total6 yr workReact3 yrAndroid SDK4 yrnon-workKotlin1 yrnon-work
Observability
Prometheus5 yrDistributed Tracing4 yrAzure Application Insights3 yrELK stack2 yrAmazon CloudWatch1 yrGrafana/Loki6 moIstio trace observability6 mo
Architecture & Patterns
Design Patterns
Singleton15 yr total8 yr workFactory12 yr total8 yr workStrategy12 yr total8 yr workBuilder8 yrAdapter7 yr
Cloud & Distributed Patterns
Cache-Aside7 yrClaim-Check4 yrFan-Out, Fan-In3 yrCompeting Consumers3 yrTransactional Outbox2 yrIdempotency2 monon-work
Architectural Styles
Domain-Driven Design (DDD)2 monon-workHexagonal Architecture2 monon-workSaga2 monon-workCQRS2 monon-workBackend-for-Frontend (BFF)2 monon-work
Methodologies
BDD1 yrTDD1 monon-work
Expert
Advanced
Intermediate
Beginner
total = all experience · work = professional · non-work = personal/study only
Selected Impact.
16+
Years of Engineering
Building software systems since 2010
8+
Years of Engineering Work Experience
Professional enterprise-scale software engineering
10+
Production Projects
On-premises, cloud, and hybrid multi-service systems
Led backend and cloud engineering across large-scale systems involving many microservices and production environments.
Led and scaled engineering teams, delegated technical work, tracked delivery timelines, actively unblocked engineers through daily collaboration, mentored engineers through code reviews and cross-team technical coordination, and supported cross-team engineering initiatives focused on performance, scalability, and reliability.
Designed and delivered Azure-based cloud-native solutions using App Services, Functions, Cosmos DB, Event Hubs, Service Bus, APIM, Bicep, Application Gateway, Front Door CDN, Storage Accounts, Microsoft Graph API, and Entra ID application registration. Also used RabbitMQ from Kubernetes on-premises and Kafka on-premises. In many cases for messages exchanged, the claim-check and outbox patterns were used.
Contributed to AWS-based solutions using Lambda, Cognito, Aurora MySQL with RDS Proxy, AWS SAM, AWS CDK, secure VPC networking, and Node.js/TypeScript Lambda APIs using TypeORM.
Delivered a production AWS cloud-native system using Angular with AWS Amplify, Cognito-based authentication (OIDC PKCE with native users and SAML federation), a custom Java authorizer on API Gateway, and role-based access control backed by Aurora RDS through RDS Proxy.
Designed and implemented event-driven architectures using Kafka, RabbitMQ, Azure Service Bus, and Azure Event Hub, applying reliability patterns including retries and asynchronous workflows.
Designed modular architecture using micro-frontends, SPI, and shared modules across backend and frontend systems, and implemented dynamic runtime extensibility using polymorphism, service loaders, dependency injection, and dynamic routing.
Introduced reusable parent/common modules, SPI modules, and shared UI libraries, enabling feature composition through runtime route and component injection based on data-driven configuration.
Achieved significant performance gains by eliminating query-in-loop patterns, introducing bulk data fetching, optimizing algorithms using O(1) lookup structures, improving concurrency stability through thread-safe random generation, and enhancing database throughput through JPA batch processing. Used also Cache-aside pattern and used thread safe approaches to avoid thread deadlocks and reduce contention, like singleton without state, ThreadLocalRandom, synchronized methods, and more recently AtomicInteger, AtomicLong and AtomicReference. Replaced Ehcache with Redis-based distributed caching to improve scalability and consistency.
Advocated Infrastructure-as-Code best practices by promoting Bicep-based provisioning over imperative scripting for multi-environment systems, and used Flyway and Liquibase for database initialization and schema evolution.
Contributed to architectural decision-making and Software Architecture Document (SAD) definition, security and compliance-related engineering, privacy/security assessment support, and browser-side rendering isolation patterns for untrusted HTML and document content.
Contributed to InfoSec and compliance-related assessment activities for Azure-based cloud systems, supporting alignment with enterprise and regulatory control frameworks such as NIST, SOC 2-type requirements, and other recognized cybersecurity certification frameworks.
Authored Kubernetes manifests and Helm charts, led migration of on-premise Spring Boot microservices into Dockerized Kubernetes environments, implemented service mesh capabilities for mTLS and observability, improved Kubernetes resilience through node-aware pod distribution, and designed resilient deployment and caching strategies across Kubernetes- and Redis-based environments.
Applied BDD testing with Cucumber/Gherkin, implemented Selenium-based end-to-end testing, built and maintained CI/CD pipelines using Jenkins, Azure DevOps, ArgoCD, Nexus OSS, and Azure Artifacts, and integrated SonarQube to improve code quality, maintainability, and release reliability.
Created a PDF creation abstraction layer as a reusable library that was using PDFBox as dependency, which helped with the creation of PDFs and used in various production projects.
Contributed to the migration of legacy monolithic systems to Spring Boot microservices, led frontend modernization from AngularJS to Angular, introduced centralized logging and monitoring using the ELK stack, delivered backend and frontend improvements across enterprise software projects, and used Apache Camel for integration workflows. Used Spring Boot, Java, jQuery, ElasticSearch as DB.
Developed backend and frontend features across enterprise software projects, improved Angular performance by avoiding DOM re-rendering bottlenecks through property-based conditional directives instead of function-based approaches, supported production deployments and CI/CD processes, and used Apache Camel with file and SFTP components. Used Spring Framework, Spring Boot, Java, AngularJS, Angular, PostgreSQL, XSD Schemas, JSON Schemas, MVC HTML, JSP Servlets, Cache-Aside pattern.
Developed backend and frontend features across enterprise software projects, supported production deployments and CI/CD processes, and used Apache Camel with file and SFTP components. Used Spring Framework, Java, AngularJS, Angular, PostgreSQL, XSD Schemas, JSON Schemas, MVC HTML, JSP Servlets.
Applied reliability patterns including idempotency keys, retry mechanisms, and asynchronous workflows.
Experience.
Senior Software Engineer & Team Lead
European Dynamics
- Led backend and cloud engineering across large-scale microservice systems on Azure and AWS, designing event-driven architectures with Kafka, RabbitMQ, and managed messaging services using claim-check and outbox patterns.
- Scaled and mentored engineering teams while driving performance, reliability, and security improvements — container orchestration with service mesh for mTLS, distributed caching, batch processing optimizations, CI/CD pipelines, and alignment with recognized security and compliance frameworks.
Senior Software Engineer
European Dynamics
- Drove migration of legacy monoliths to Spring Boot microservices and modernized frontends from AngularJS to Angular.
- Introduced centralized logging and monitoring using a search and analytics stack, and built integration workflows using Apache Camel.
Software Engineer
European Dynamics
- Delivered backend and frontend features across enterprise projects using Spring Boot, Java, Angular/AngularJS, and PostgreSQL, applying the Cache-Aside pattern and XSD/JSON schema validation.
- Improved frontend rendering performance through targeted change-detection optimizations, and built integration workflows using Apache Camel with file and SFTP components.
Software Developer
European Dynamics
- Developed backend and frontend features across enterprise software projects using Spring Framework, Java, Angular/AngularJS, and PostgreSQL.
- Supported production deployments and CI/CD processes, and built integration workflows using Apache Camel with file and SFTP components.
Military Service — Special Forces
Hellenic Army · Amphibious Commando
- Completed mandatory military service in the Hellenic Army Special Forces in an amphibious commando role.
- Developed discipline, resilience, teamwork, and the ability to perform effectively under pressure.
Certifications.
Professional Certifications
Azure Data Fundamentals
Microsoft
Validity: 2026 - No expiration
Azure Administrator Associate
Microsoft
Validity: 2025 - Present
Azure Developer Associate
Microsoft
Validity: 2025 - Present
Azure Fundamentals
Microsoft
Validity: 2024 - No expiration
Certificates of Completion
Education
Bachelor Thesis
Software System for Collecting Cellular and Wi-Fi Network Information Using an Android Device
View ThesisLanguages
Greek
Greece
Native
Native language
English
United States
Professional Working Proficiency
Michigan HAU B2 (2007) · Duolingo score: 130
Japanese
Japan
Elementary Proficiency
Duolingo score: 12
Current Interests.
Beyond day-to-day engineering, areas of active exploration and development.
Fintech Patterns, Architectures & Payments
Hands-on with hexagonal architecture, DDD, CQRS, Saga orchestration, transactional outbox, double-entry ledgers, multi-currency FX, idempotency, and resilience patterns for payment-grade systems.
Android Product Development
Building mobile applications with a focus on real-world utility and modern Android development practices.
Applied AI & Computer Vision
Occasional experimentation with image recognition and object detection in Python/TensorFlow.
Data Platform Exploration
Light exploration of lakehouse architectures and modern data engineering workflows.