Marcel Seifert - Lead Developer / Software Architect

Q: Where is Marcel based?

Marcel is based in Hamburg, Germany and can operate in on-site , hybrid , and remote work models.

Q: What languages does Marcel speak?

Marcel speaks the following languages: German (Native), English (Advanced) .

Q: How many years of experience does Marcel have?

Marcel has at least 23 years of experience. During this time, Marcel has worked in at least 9 different roles and for 15 different companies . The average length of individual experience is 2 years and 6 months . Note that Marcel may not have shared all experience and actually has more experience.

Q: What is Marcel's latest experience?

Marcel's most recent position is Lead Developer / Software Architect at Rezeptprüfstelle Duderstadt GmbH .

Q: What companies has Marcel worked for in recent years?

In recent years, Marcel has worked for Rezeptprüfstelle Duderstadt GmbH , Beyond Chiefs GmbH , Vaillant GmbH , OTTO GmbH , and Feuerring GmbH .

Q: Which industries is Marcel most experienced in?

Marcel is most experienced in industries like Banking and Finance , Insurance , and Information Technology . Marcel also has some experience in Retail , Healthcare , and Energy .

Q: Which business areas is Marcel most experienced in?

Marcel is most experienced in business areas like Information Technology , Product Development , and Business Intelligence . Marcel also has some experience in Human Resources .

Q: Which industries has Marcel worked in recently?

Marcel has recently worked in industries like Information Technology , Healthcare , and Retail .

Q: Which business areas has Marcel worked in recently?

Marcel has recently worked in business areas like Information Technology , Product Development , and Human Resources .

Recommended expert

Hamburg, Germany

Experience

Aug 2024 - Present

1 year 8 months

Lead Developer / Software Architect

Rezeptprüfstelle Duderstadt GmbH

Responsible for the redevelopment of a billing and validation software for prescriptions to fully check and analyze e-prescriptions for correctness (content, billing)
System consists of multiple contexts running as services (Docker containers):
Checking and processing data deliveries via FTP and email
Management of invoicing, clearings, deductions and offsets
Management and execution of validation rules and test sets
Analytics 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

May 2024 - Present

1 year 11 months

Beyond Chiefs GmbH

Design (analysis, PoC) and development of a platform for matching 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

Jul 2023 - Jul 2024

1 year 1 month

Senior Developer

Vaillant GmbH

Further development of the B2B platform for integrating consumption data and controlling various heating systems (gas boilers, heat pumps) via public REST APIs for B2B partners
Platform consists of multiple microservices communicating synchronously (REST) and asynchronously (Kafka)
Data persistence in MongoDB or service-specific via Kafka Streams
Access control through Azure API Management and API specification described in the Azure Developer Portal
Developer Stack: Java 17–21, Go, Azure / APIM / Developer Portal, Spring Boot 2–3, Gradle, MongoDB (Atlas), Kafka / Kafka Streams, REST API / OpenAPI, GitHub / GitHub Actions, JWT / OAuth2, DevOps, Terraform, Instana, Grafana, Kibana, JUnit, Testcontainers, Mockito, Spring Boot Test, K6

Jan 2022 - Jun 2023

1 year 6 months

OTTO GmbH

Implementation of a scalable microservice architecture with Java 17 and Spring Boot on AWS cloud for ingesting and processing product data (Excel, CSV, JSON) via web UI (React), FTP and REST API
Integration of product data into surrounding systems (e.g. marketplace) through asynchronous interfaces (Kafka)
Monitoring services 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, OpenTelemetry, ElasticSearch, DevOps, Scrum, CI/CD, JUnit, Testcontainers, Mockito, Spring Boot Test, Testcafe

Nov 2021 - Dec 2024

3 years 2 months

Feuerring GmbH

Development (part-time) and continuous improvement of a comprehensive CRM platform (contacts, email, calls, tasks, documents) as a modular monolith in Java 21 on Azure cloud with 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

Jan 2021 - Dec 2021

1 year

Intersoft AG

Further development of a new insurance platform for household contents and liability based on a microservice architecture with Java 11, Vue and Spring Boot in an on-premises cloud (Rancher, Kubernetes, 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

Jun 2020 - Dec 2020

7 months

dealerdesk GmbH

Relaunch of the CRM platform for car dealers as a modulith in Java 11 and Spring Boot on Google Cloud
Launch of an online marketplace for electric vehicles as a standalone frontend with Vue and TypeScript with REST calls to the CRM platform
Developer Stack: Java 11, Spring Boot, Vue / Vuetify, TypeScript, Google Cloud, GitLab, JUnit, Testcontainers, Mockito, Spring Boot Test

Dec 2019 - Apr 2020

5 months

Freelancer

e.kundenservice Netz GmbH (e.ON)

Creation of widgets for LoRa devices and dashboards to display indoor climate in buildings
Processing of IoT device data and integration within ThingsBoard
Developer Stack: Angular(JS), CSS, HTML, JavaScript, ThingsBoard

Apr 2019 - Apr 2020

1 year 1 month

Freelancer

Fielmann AG

Providing self-service features for the registration process, order management and email sending based on a microservice landscape in AWS using .NET and C# as well as newer services in Kotlin and Spring Boot
Migration from .NET Core 2.1 to 3.1 / 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

Jun 2018 - Mar 2019

10 months

Senior Java Server / Backend Developer (Freelancer)

Starfinanz GmbH

Integration of credit card and overdraft credit features and connection to the OSPEx bank interface in a Java 11 Spring Boot application for the Yomo banking app
Refactoring of the S-APP by moving business logic to 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 encryption

Feb 2018 - May 2018

4 months

Hamburg, Germany

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

Mar 2013 - Jan 2018

4 years 11 months

Hamburg, Germany

Senior Consultant

Swiss Life Deutschland Operations GmbH

Software architect for interfaces to back-office systems and building a new system landscape (Microservices, private on-premise cloud)
Representative at VDG New Development Technologies
Projects:
Application entry system (Spring Boot, RabbitMQ, ElasticStack, Cloud Foundry)
Evaluation of a PaaS environment
Document archive service for storing and retrieving internal archive systems (JAX-RS, JSON, JPA, EJB3, encryption with BouncyCastle)
Integration of a K&I system with surrounding legacy systems (JAX-RS, JSON, JPA, EJB3)
Harmonization of customer management systems
Migration interface for monitoring (Angular)
New development of a dashboard system based on portlets (JSR 286, Primefaces, JPA, Liferay 6)

Oct 2010 - Feb 2013

2 years 5 months

Adliswil, Switzerland

Application Developer

Generali Schweiz

Development and enhancement of portlets for the broker portal (JSF, Portlets, JPA, JAX-WS, XML, WS-Security, SAML, SSL/TLS, gSOAP)
Projects:
Self-Service Portal
Data inquiry for commissions and contract data

Jul 2009 - Sep 2010

1 year 3 months

Zürich, Switzerland

Application Engineer (Java)

UBS Schweiz

Support and further development of the pending items system based on Java, PEGA (BPMN), EJB, IBM MQ, Struts
Project: PI (PendingItems) for Switzerland and International

Feb 2003 - Jun 2009

6 years 5 months

Hamburg, Germany

Software Developer, from 2008-10-01 Team Lead Web Applications

tecis FDL AG

Support and further development of all web applications and the CMS system based on Lotus Domino; technical responsibility for the SitLap product
Projects:
Redesign of the SitLap product based on JSF / RichFaces and Hibernate
SitLap (Java, Struts, Apache FOP): financial planning tool including concept creation (PDF)
Business Report (Java, Struts): reporting and BI tool for sales
Excalibur (Java, Eclipse RCP, Hibernate): desktop application for capturing customer, advisor, application, and commission data

Industry Experience

See where this freelancer has spent most of their professional time.

Experienced in Banking and Finance, Insurance, Information Technology, Retail, Healthcare, and Energy.

Banking and Finance

Insurance

Information Technology

Retail

Healthcare

Energy

Business Area Experience

See which departments and functions this freelancer has contributed to most.

Experienced in Information Technology, Product Development, Business Intelligence, and Human Resources.

Information Technology

Product Development

Business Intelligence

Human Resources

Skills

Java
Kotlin
Type- / Javascript
C#
Go
Html / Css / Sass
Elasticsearch / Mongodb / Postresql
Sql92
Oracle Pl/sql
Apache Kafka
Nunit / Junit / Wiremock / Rest Assured
Angular / React / Vue
Vuetify / Mui
Git / Svn
Jenkins / Concourse / Gitlab
Maven / Gradle
.Net Core
Spring Boot / Spring Data / Spring Cloud
Terraform
Docker / Kubernetes

Languages

German

Native

English

Advanced

Education

Aug 2000 - Jan 2003

tecis Service AG

IT specialist in application development · Hamburg, Germany

Certifications & licenses

ITIL V3 Foundation

OMG Certified UML Professional Fundamental

Oracle Certified Master, Java EE 5 Enterprise Architect

Sun certified Java Programmer (Java 5)

Sun certified Web Developer (J2EE 1.4)

iSAQB® Certified Professional for Software Architecture, Advanced Level

tecis Management Development Program

Statistics

Experience

Total positions 15

Experience in Banking and Finance 8.5 y

Avg length 1 y 10 m

Longest experience 6 y 4 m

Global Experience

Countries worked in 2 (Germany, Switzerland)

Primary country Germany

Expertise

Recent roles Lead Developer / Software Architect, Senior Developer, Freelancer

Main industries Banking and Finance, Insurance, Information Technology

Main business areas Information Technology, Product Development, Business Intelligence

Qualifications

Certifications earned 7

Profile

Created

September 2025

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Frequently asked questions

Do you have questions? Here you can find further information.

Where is Marcel based?

Marcel is based in Hamburg, Germany and can operate in on-site, hybrid, and remote work models.

What languages does Marcel speak?

Marcel speaks the following languages: German (Native), English (Advanced).

How many years of experience does Marcel have?

Marcel has at least 23 years of experience. During this time, Marcel has worked in at least 9 different roles and for 15 different companies. The average length of individual experience is 2 years and 6 months. Note that Marcel may not have shared all experience and actually has more experience.

What roles would Marcel be best suited for?

Based on recent experience, Marcel would be well-suited for roles such as: Lead Developer / Software Architect, Senior Developer, Freelancer.

What is Marcel's latest experience?

Marcel's most recent position is Lead Developer / Software Architect at Rezeptprüfstelle Duderstadt GmbH.

What companies has Marcel worked for in recent years?

In recent years, Marcel has worked for Rezeptprüfstelle Duderstadt GmbH, Beyond Chiefs GmbH, Vaillant GmbH, OTTO GmbH, and Feuerring GmbH.

Which industries is Marcel most experienced in?

Marcel is most experienced in industries like Banking and Finance, Insurance, and Information Technology. Marcel also has some experience in Retail, Healthcare, and Energy.

Which business areas is Marcel most experienced in?

Marcel is most experienced in business areas like Information Technology, Product Development, and Business Intelligence. Marcel also has some experience in Human Resources.

Which industries has Marcel worked in recently?

Marcel has recently worked in industries like Information Technology, Healthcare, and Retail.

Which business areas has Marcel worked in recently?

Marcel has recently worked in business areas like Information Technology, Product Development, and Human Resources.

What is Marcel's education?

Marcel attended tecis Service AG for IT specialist in application development.

Does Marcel have any certificates?

Marcel has 7 certificates. Among them, these include: ITIL V3 Foundation, OMG Certified UML Professional Fundamental, Oracle Certified Master, and Java EE 5 Enterprise Architect.

What is the availability of Marcel?

Marcel will be available full-time from April 2026.

What is the rate of Marcel?

Marcel's rate depends on the specific project requirements. Please use the Meet button on the profile to schedule a meeting and discuss the details.