Jan H. - Senior Software Engineer

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Berlin, Germany

Experience

Jan 2025 - Jun 2025

6 months

Senior Software Engineer

Helmholtz Centre for Environmental Research (UFZ)

Spearheaded implementation of a new authentication system across PHP backend, Vue.js web application, and Ionic-based iOS/Android mobile apps to ensure compliance with Keycloak security requirements
Owned requirements engineering and product roadmap development, aligning technical initiatives with business objectives and stakeholder needs
Delivered multiple high-impact features across web and mobile platforms, enhancing user experience and expanding system capabilities
Facilitated knowledge transfer through comprehensive documentation and handover processes to ensure continuity of operations

Jul 2021 - Present

4 years 3 months

Berlin, Germany

Technical Founder

Telemarie

Conducted trade-off analyses for tech stacks and led the design and implementation of the software architecture, including mobile and backend solutions
Facilitated event storming workshops to define solution domains for DDD and architecture
Defined overall product and organizational strategic direction and explored new forms like steward ownership
Guided adoption of Lean and Agile principles, implemented lean prototypes, and ensured adherence to Lean Startup processes
Facilitated workshops, retrospectives, and futurespectives to align team, resolve conflicts, and foster collaboration
Technologies: Flutter, Google Cloud, Firebase, Android, iOS, Hexnode MDM, proto.io
Organizational Methods: Lean startup, lean canvas, event storming, retrospectives

Jan 2015 - Jun 2021

6 years 6 months

Delivery Lead

Zalon by Zalando

Initiated implementation using Scala Play framework with Postgres and AWS and expanded architecture incorporating a microservices strategy
Commanded delivery teams in journey from 0 to ~€50M revenue, collaborating with business on tech-critical decisions and nurturing cross-functional teams
Held accountability for entire application and system architecture, including microservice strategy, AWS, Kubernetes, and Docker
Technologies: Scala, Akka, Scalaz, Scalatest, Play2, Postgres, AWS (EC2, Lambda, RDS, Route53, CloudFront, S3), Kubernetes, Grafana, NewRelic/AppDynamics
Organizational Methods: Lean and Agile methodologies, event storming workshops for goal alignment

Mar 2013 - Dec 2014

1 year 10 months

Technical Founder

get2play GmbH

Responsible for implementation of platform and coordination of development
Defined product and organizational strategic direction and explored steward ownership models
Guided adoption of Lean and Agile principles, implemented lean prototypes, and iterated from product/solution-fit to product/market-fit
Facilitated workshops, retrospectives, and futurespectives to align team, resolve conflicts, and foster collaboration
Technologies: Play2, Scala, JavaScript, WebAudio, jQuery, Heroku, AWS (EC2, S3, Media Services), Mixpanel, MongoDB
Organizational Methods: Lean startup, lean canvas, event storming, retrospectives

Apr 2011 - Dec 2012

1 year 9 months

Software Developer

PARSHIP GmbH

Developed major improvements of online matchmaking platform and new mobile web application
Overhauled legacy modules to object-oriented architecture to improve performance and maintainability
Initiated and implemented build and configuration management tools to facilitate continuous deployment
Collaborated with team members to ensure code quality and conducted peer reviews
Technologies: Java, Microservices
Organizational Methods: Agile development, Continuous Integration/Continuous Deployment, Code reviews

Aug 2009 - Mar 2011

1 year 8 months

Software Developer

edict egaming GmbH

Created multiplatform desktop Java client for online casino admin and backoffice, ensuring compatibility and performance across operating systems
Developed robust automated acceptance tests to validate features and ensure quality assurance prior to deployment
Technologies: Java, Java Swing, Java FX, REST APIs
Organizational Methods: Agile development, RESTful architecture, Automated Acceptance Testing

Dec 2008 - Aug 2009

9 months

Consultant and Developer

Freelancer

Developed ERP modules for Creations Media using Java
Consulted at Heitcon3 and Creations Media on system and software architectures, OO analysis and design, TDD, and Scrum

Jan 2007 - Nov 2008

1 year 11 months

Senior Consultant

Steria Mummert Consulting AG

Led migration of CRM application suite to web-based SAP applications using SAP WAS (ABAP)
Created and executed roadmap for integrated CRM and sales channel management landscape used by 500–1000 users
Conducted business process and requirements analysis for solution modeling and implementation
Introduced Agile principles and served as Scrum Master for a team of 7 members
Provided training and consulting in OO design and system architectures
Developed GUI using BSP and HTML and implemented business and data layers using ABAP Objects, Object Services, Open SQL, and XML
Technologies: SAP WAS (ABAP), BSP, HTML, Open SQL, XML
Organizational Methods: Agile principles, Scrum, Object-Oriented Design, Business Process Analysis

Nov 2004 - Jan 2007

2 years 3 months

Technology Consultant

Accenture

Served as Assistant Project Manager for transactional data portal with ~500 users and led development team of 5 members
Conducted business process and requirements analysis and functional design
Oversaw technical design and implementation of services and change requests using EJBs, ABAP Objects, WebDynpros, and JSPs
Crafted technical design for validation module with complex algebra for financial consolidation and custom application for rule definitions
Defined data model for rules using XML and XML Schemas and developed business and data layers with Java EJB, JDO, and JAX
Technologies: EJB, ABAP Objects, WebDynpros, JSPs, XML, XML Schemas, Java EJB, JDO, JAX
Organizational Methods: Project Management, Business Process and Requirements Analysis, Technical Design, Module Design

Aug 2001 - Mar 2004

2 years 8 months

Research Assistant

University of Hamburg

Worked in artificial intelligence focusing on knowledge representation and processing to verify theories on human spatial concepts and processes
Built virtual robot to interpret textual route descriptions, create internal representations, and navigate within artificial environment
Developed application interface and key knowledge representation modules in Java and text-interpretation module in Prolog integrated via C-based interface
Used complex geometric framework for artificial environment operations and conclusions
Technologies: Java, Prolog, C, Artificial Intelligence, Knowledge Representation

Summary

I'm a hands-on software engineer with deep technical expertise who gets energized by adjacent fields like organizational design, product strategy, and modern work methodologies. My sweet spot: combining solid engineering fundamentals with state-of-the-art approaches to deliver real business value.

Technical depth: Backend-focused (Scala, Java, cloud platforms) with T-shaped skills across mobile, frontend, and architecture
Business-tech bridge: Strong communication skills that translate between engineering realities and business needs
Delivery focus: From startup MVPs to €50M+ products
Modern methods: Lean Startup, Agile, DDD, and AI-enhanced development workflows
Hands-on leadership: Code, architect, facilitate—whatever gets the job done

I thrive at the intersection of technical excellence and smart business decisions, helping teams navigate complex trade-offs while keeping everyone aligned.

Whether it's technical co-founding, scaling delivery teams, or optimizing how teams work together, I love creating systems and cultures that deliver value fast.