Marcel S.
Lead Developer / Software Architect
Experience
Lead Developer / Software Architect
Rezeptprüfstelle Duderstadt GmbH
Responsible for redeveloping billing and validation software for prescriptions
Full verification and analysis of e-prescriptions for correctness (content, billing)
System consists of multiple contexts as Docker containers:
Reviewing and processing data deliveries via FTP and email
Managing invoices, clearings, discounts, and write-offs
Managing and executing validation rules and checklists
Reporting based on Metabase
Developer stack: Kotlin, Vue 3, Vuetify 3, ANTLR, Spring Boot 3, REST API, Gradle, Docker, GitLab, PostgreSQL, Kafka, Keycloak, Scrum, Grafana, Loki, Testcontainers, Prometheus
Software Developer (Part-time)
Beyond Chiefs GmbH
Designing (analysis, PoC) and building a platform to match freelancers and employees with projects and jobs based on AI-powered skill analysis
Developer stack: Java, Go, TypeScript, Node.js, Vue 3, Flowbite, Spring Boot, Spring AI, LLM, RAG, PostgresDB with vector extension, GitHub, Google Cloud, Kubernetes
Senior Developer
Vaillant GmbH
Enhancing the B2B platform to integrate consumption data and control various heating systems (gas boilers, heat pumps) via public REST APIs
Platform consists of multiple microservices communicating synchronously (REST) and asynchronously (Kafka)
Persistence in MongoDB Atlas or service-bound via Kafka Streams
Access control via Azure API Management and specification in the Azure Developer Portal
Developer stack: Java 17-21, Go, Azure APIM, Spring Boot 2-3, Gradle, MongoDB, Kafka, OpenAPI, GitHub Actions, JWT/OAuth2, DevOps, Terraform, Instana, Grafana, Kibana, JUnit, Testcontainers, Mockito, Spring Boot Test, K6
Software Developer
OTTO GmbH
Implementing a scalable microservice architecture with Java 17 and Spring Boot in the AWS cloud for ingesting and processing product data (Excel, CSV, JSON)
Entry points: web UI (React), FTP, and REST API
Asynchronous integration of product data via Kafka into surrounding systems (e.g., marketplace)
Monitoring with Grafana and Prometheus, logging with AWS CloudWatch, tracing with Elastic APM and OpenTelemetry
Developer stack: Java 17, AWS, Kafka, MongoDB, PostgreSQL, React, MUI, Spring Boot, Gradle, Terraform, GitHub, Elasticsearch, DevOps, Scrum, CI/CD, JUnit, Testcontainers, Mockito, Spring Boot Test, TestCafe
Software Developer (Part-time)
Feuerring GmbH
Building and continuously improving a comprehensive CRM platform (contacts, email, calls, tasks, documents) as a module-based monolith in Java 21 in the Azure cloud
Using Spring Boot 3, Vue, and Docker
Developer stack: Java 21, Azure, Vue, Vuetify, Spring Boot 3, Gradle, PostgreSQL, GitHub, Docker, JUnit, Testcontainers, Mockito, Spring Boot Test
Software Developer
Intersoft AG
Further development of a new insurance platform for household contents and liability insurance based on a microservice architecture with Java 11, Vue and Spring Boot
On-premise cloud with Rancher, Kubernetes and Docker
Developer Stack: Java 11, PostgreSQL, Oracle DB, Spring Boot, Vue, Vuetify, TypeScript, Kubernetes, Rancher, Gradle, Gitea, Jenkins, DevOps, Scrum, CI/CD, JUnit, Testcontainers, Mockito, Spring Boot Test, PowerMock
Software Developer
dealerdesk GmbH
Relaunch of the CRM platform for car dealers as a modulith in Java 11 and Spring Boot on Google Cloud
Launch of a car marketplace for electric vehicles with a standalone frontend in Vue and TypeScript
Developer Stack: Java 11, Spring Boot, Vue, Vuetify, TypeScript, Google Cloud, GitLab, JUnit, Testcontainers, Mockito, Spring Boot Test
Freelancer
e.kundenservice Netz GmbH (e.ON)
Creation of widgets for LoRa devices and dashboards to monitor indoor climate data in buildings
Processing IoT data and integration via ThingsBoard
Developer Stack: AngularJS, CSS, HTML, JavaScript, ThingsBoard
Freelancer
Fielmann AG
Providing self-service functionality for registration processes, order management and email sending in the "My Fielmann Account" area
Microservice architecture in AWS using .NET Core and C# as well as new services in Kotlin and Spring Boot
Migration from .NET Core 2.1 to 3.1 and C# 8
Developer Stack: .NET Core, C#, Kotlin, Spring Boot, TypeScript, React, REST, DDD, Kafka, Concourse, Kubernetes, Helm, Docker, AWS, PostgreSQL, Scrum, Git, GitHub, SSL/TLS, JUnit, Testcontainers, Mockito, Spring Boot Test, TestCafe
Senior Java Server / Backend Developer
Starfinanz GmbH
Integration of credit card and overdraft features into the yomo banking app
Integration with the bank interface OSPEx in a Java 11 Spring Boot application
Restructuring of the S-APP by moving business logic into Frontend as a Service and Backend as a Service
Developer Stack: REST, Swagger, Spring Boot 2, Java 8, Jenkins, Gradle, Scrum, Git, Bitbucket, SSL/TLS, asymmetric payload encryption
Senior Software Developer
PLATH GmbH
Further development of the ICAS platform
Developer Stack: Eclipse RCP, OSGi, Spring, Servlet, Data Distribution Service (OMG, RTI), Java 8, Git
Principal Consultant
Swiss Life Deutschland Operations GmbH
Software architecture and interfaces to back-office systems
Setting up a new system landscape (microservice, private on-premise cloud)
Representation at VDG "New Development Technologies"
Projects:
Application entry system with Spring Boot, RabbitMQ, Elastic Stack and Cloud Foundry
Evaluation of a PaaS environment
Document archive service (JAX-RS, JSON, JPA, EJB3, BouncyCastle CryptoFramework)
Integration of a K&I system (JAX-RS, JSON, JPA, EJB3)
Harmonization of customer management systems
Migration interface (Angular)
New development of a key performance indicator system based on portlets (JSR 286, PrimeFaces, JPA, Liferay 6)
Application Developer
Generali Schweiz
Building and enhancing portlets for the broker portal
Technologies: JSF, Portlets, JPA, JAX-WS, XML, WS-Security, SAML, SSL/TLS, gSOAP
Projects: Self-service portal; information on commissions and contract data
Application Engineer (Java)
UBS Schweiz
Support and further development of the pending items system based on Java, PEGA (BPMN), EJB, IBM MQ and Struts
Project: PendingItems (PI) for Switzerland and international
Team Lead Web Applications
tecis FDL AG
Leading the web applications team and coordinating the further development of web projects
Maintaining technical responsibility for SitLap
Software Developer
tecis FDL AG
Support and further development of web applications and CMS based on Lotus Domino
Technical responsibility for the SitLap product
Projects:
Redesign of SitLap using JSF, RichFaces and Hibernate
SitLap financial planning tool with Java, Struts and Apache FOP
Business report and BI tool with Java and Struts
Excalibur desktop application with Java, Eclipse RCP and Hibernate
Languages
Education
Tecis Service AG
IT Specialist in Application Development · Hamburg, Germany
Certifications & licenses
ISaqb® Certified Professional For Software Architecture, Advanced Level
ISaqb®
Itil V3 Foundation
Omg Certified Uml Professional Fundamental
OMG
Oracle Certified Master, Java Ee 5 Enterprise Architect
Oracle
Sun Certified Java Programmer (Java 5)
Sun
Sun Certified Web Developer (J2Ee 1.4)
Sun
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