Mert Yagci

Freelance Senior Java Cloud Engineer

9+ years as a Java freelancer with Spring Boot, Kubernetes, Azure and Terraform — cloud-native systems for Rhine-Main and remote. I also build software in an AI-driven way.

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About

Freelance Senior Java Cloud Engineer based in Offenbach am Main (Rhine-Main) with over 9 years of experience designing, building and operating cloud-native microservice systems based on Spring Boot, Kubernetes, OpenShift and Microsoft Azure. Proven expertise in full cloud migrations (on-premises/AWS → Azure), production-ready CI/CD pipelines (Jenkins, Helm, Terraform) and DevOps integration in enterprise landscapes. I also build software in an AI-driven way — from LLM integrations to faster feature delivery with modern AI workflows. Project references at Deutsche Bahn, Union Investment, Toll Collect, SVG and SAP.

I help teams with architecture, implementation and reliable delivery pipelines — and ship features using AI-assisted development workflows.

Education

Bachelor of Science – Business Information Systems International

Frankfurt University of Applied Sciences (FRA-UAS)

09/2012 – 09/2016 · 2.1 · Controlling

Languages

  • TurkishNative
  • GermanNear-native (C2)
  • EnglishGood (B2)

Certificates

  • Professional Scrum Developer I (PSD I) — Scrum.org
  • Developing Solutions for Microsoft Azure — Microsoft
  • Web application security
  • Software architecture for web applications
  • Developing Web Apps with SAPUI5 — SAP
  • IP-Multimedia Systems – telephony in fixed and mobile networks

Projects

Selected engagements across rail, finance, telematics and enterprise software.

  • SVG Bundes-Zentralgenossenschaft Straßenverkehr eG

    10/2022 – 06/2026

    Senior Java Cloud Engineer (Cloud & Microservices)

    Full cloud migration from on-premises/AWS to Microsoft Azure plus design and operations of cloud-native microservices for digital service and integration platforms.

    • On-premises/AWS → Azure migration with significantly improved scalability
    • Cloud-native microservices with Spring Boot and Kubernetes
    • CI/CD with Bitbucket Pipelines and Helm for testing, staging and production
    • Event-driven integration via Azure Service Bus; infrastructure with Terraform
    • Database optimization, Redis caching and observability with Grafana
    • Java
    • Spring Boot
    • Kubernetes
    • Docker
    • Microsoft Azure
    • Terraform
    • Helm
    • Bitbucket (Git)
    • Bitbucket Pipelines
    • Azure Service Bus
    • MS SQL Server
    • PostgreSQL
    • Redis
    • Keycloak
    • Angular

    Read case study

  • ATIS systems GmbH

    10/2019 – 08/2022

    Java Developer / Systems Engineer

    Development and modernization of technical communication and integration solutions in security- and network-oriented systems. Migration of existing C applications to Java, integration of diverse communication interfaces, and operations of productive Linux environments.

    • Migration of a safety-critical legacy application from C to Java
    • Development of web- and TCP-based communication interfaces (SOAP, JSON, SSL)
    • Administration of productive Linux servers; maintenance of Jenkins build pipelines
    • Test automation following TDD; root-cause analysis and fixes in real-time systems
    • Java
    • Maven
    • Gradle
    • Apache Ivy
    • Jenkins
    • Linux
    • TCP/IP
    • SOAP
    • JSON
    • SSL
    • JUnit
    • TDD
    • CI/CD

    Read case study

  • Toll Collect (via CDI AG)

    08/2019 – 09/2019

    Consultant / Java Backend Developer — enterprise integration

    Further development and stabilization of business-critical systems in the national toll-collection domain.

    • Analysis and resolution of critical production defects
    • REST interfaces with Spring Boot
    • Automated tests following TDD (JUnit, JGiven)
    • Java EE
    • Spring Boot
    • JAX-RS
    • JPA
    • Oracle 12c
    • JUnit
    • JGiven
    • Maven
    • Jenkins
    • TDD

    Read case study

  • Union Investment (via CDI AG)

    01/2019 – 04/2019

    Consultant / Java Backend Developer — problem management regulatory reporting

    Root-cause analysis and fixes in regulatory reporting plus BPM process development with Camunda in a complex enterprise landscape.

    • Analysis and correction of complex defects in a JBoss/WildFly Swarm environment
    • BPM process design with Camunda (BPMN)
    • Integration testing across a heterogeneous enterprise landscape
    • Java EE
    • Drools
    • ActiveMQ
    • Docker
    • Oracle 12c
    • Camunda
    • BPMN
    • Maven
    • Jenkins

    Read case study

  • Deutsche Bahn (via CDI AG)

    06/2017 – 12/2018

    Java Backend Developer — VENDO reservation system

    Greenfield development of the VENDO reservation system based on microservices, OpenShift and RabbitMQ in a cross-functional Scrum team.

    • Backend microservices following Domain-Driven Design
    • Deployment and operations of containerized services on OpenShift / AWS
    • Asynchronous train-journey processing via RabbitMQ
    • CI/CD with Jenkins and GitLab CI/CD; performance tests with Gatling
    • Java 8
    • Thorntail/WildFly Swarm
    • MongoDB
    • RabbitMQ
    • OpenShift
    • AWS
    • Docker
    • Jenkins
    • GitLab CI/CD
    • DDD

    Read case study

  • SAP SE

    08/2015 – 01/2016

    Intern — SAP BPM

    BPM prototyping with OData (Apache Olingo), JPA and SAPUI5 in the SAP enterprise stack, including mobile app development.

    • Prototyping with Apache Olingo (OData), data dictionary and JPA
    • Automated tests with JUnit; pair programming
    • Business-process orchestration via SMP Server; SAPUI5 analytics app
    • Apache Olingo
    • JPA
    • OData
    • JUnit
    • SAPUI5
    • SAP Mobile Platform 3.0
    • SAP NetWeaver

    Read case study

Skills

Hands-on core competencies: backend, cloud, containers, infrastructure as code and AI-driven software development.

Download skill matrix (Excel)CV (PDF)

Backend

  • Java (SE/EE)Excellent8+ Years
  • Spring Boot / Spring FrameworkExcellent8+ Years
  • Microservices / DDDExcellent5+ Years
  • REST APIs / JPA / HibernateExcellent8+ Years
  • JAX-RSGood3+ Years
  • Apache CamelGood2–3 Years
  • MapStructGood3+ Years
  • DroolsGood2+ Years
  • KotlinBasic1+ Years
  • GoBasic1+ Years

Cloud & DevOps

  • KubernetesExcellent4–5 Years
  • DockerExcellent5+ Years
  • OpenShift / OKDExcellent2–3 Years
  • Microsoft AzureExcellent3+ Years
  • TerraformExcellent2–3 Years
  • CI/CD (Jenkins / Helm)Excellent5+ Years
  • GitLab CI/CDExcellent5+ Years
  • Bitbucket PipelinesExcellent3+ Years
  • YAMLExcellent4+ Years
  • Azure FunctionsGood2–3 Years
  • GrafanaGood4–5 Years
  • LinuxGood5+ Years
  • VMware (Workstation)Basic1+ Years

Databases

  • Microsoft SQL ServerExcellent8+ Years
  • PostgreSQLExcellent8+ Years
  • MySQLGood3+ Years
  • Oracle 12cGood2–3 Years
  • MongoDBGood3+ Years
  • RedisGood3+ Years

Security

  • Keycloak / OAuth2Good3+ Years
  • OpenID ConnectGood3+ Years

Testing

  • JUnitExcellent8+ Years
  • TDDExcellent8+ Years
  • Integration testsExcellent8+ Years
  • MockitoGood5+ Years
  • CucumberGood3+ Years
  • GatlingGood3+ Years
  • SonarQubeGood3+ Years

Messaging

  • RabbitMQExcellent4–5 Years
  • Azure Service BusExcellent3+ Years
  • ActiveMQGood4–5 Years
  • JMSGood4–5 Years
  • SOAP / REST / API integrationGood5+ Years
  • Apache KafkaBasic1+ Years

BPM

  • Camunda / BPMNGood1–2 Years
  • Workflow EnginesGood1–2 Years
  • Business process automationGood1–2 Years

Frontend

  • Angular / TypeScriptGood3+ Years
  • JavaScriptGood3+ Years
  • HTML / CSSGood3+ Years

Tools

  • Git / BitbucketExcellent8+ Years
  • GitLab CI/CDExcellent5+ Years
  • Bitbucket PipelinesExcellent3+ Years
  • MavenExcellent8+ Years
  • IntelliJ IDEAExcellent8+ Years
  • ScrumExcellent5+ Years
  • DevOpsExcellent5+ Years
  • GradleGood3+ Years
  • JiraGood5+ Years
  • ConfluenceGood5+ Years
  • NexusGood3+ Years
  • Code reviewsGood5+ Years

AI

  • AI-driven software developmentGood1–2 Years
  • LLM API integration (OpenAI)Good1–2 Years
  • AI-assisted feature developmentGood1–2 Years
  • Prompt EngineeringGood1–2 Years
  • Python automationGood2+ Years

Services

Software development, cloud architecture, DevOps and migration — focused on measurable outcomes.

  • Software development

    Backend & frontend

    Building robust backends with Java/Spring Boot and modern frontends with Angular and TypeScript — including API design, tests and long-term maintainability.

  • SaaS / cloud architecture

    System design & scale

    Design and delivery of cloud-native microservice architectures focused on scalability, integration readiness and long-term evolution.

  • DevOps & cloud

    Deployment & operations

    Operations and deployment with Kubernetes, Helm, Docker, Azure and Terraform — including CI/CD pipelines for testing, staging and production.

  • Maintenance & migration

    Existing systems

    Modernizing existing systems, cloud migrations, performance optimization, sustainable bug fixing and technical support.

Topics & services

Focused pages on Java freelancing, cloud migration, Kubernetes and AI-driven development.

Contact

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