Sebastian W.-AI-Native Engineering Lead & Senior SAP ABAP Developer · SAP S/4HANA · Solution Architecture
Check rate
Experience
Senior SAP ABAP Developer / Solution Architect
Confidential Client
AI-Native S/4HANA Custom Development
Solution architecture and implementation of an extensive SAP S/4HANA custom solution replacing required retail/POS standard functionality directly in S/4HANA.
- Architecture and technical design for inbound, persistence, enrichment, validation, aggregation and outbound processing
- Modular SAP ABAP / ABAP OO implementation based on Clean Core, Clean Code and testability principles
- AI-native development workflow with AI-generated implementation and test code
- Orchestration of specialized AI roles for discovery, planning, development and independent reviews
- Decision Freeze, Build Plans and Quality Gates for controlled AI-based delivery
- Human Design Authority for architectural decisions, SAP validation, technical acceptance and release
IMPACT ACHIEVED:
- Productive use of an AI-native engineering model in a real enterprise SAP project
- Extensive modular custom solution with several hundred SAP development objects
- High maintainability and testability through modular architecture, automated tests and structured reviews
- Replacement of required standard functionality to reduce recurring licensing and operating costs
Engineering Lead / Senior SAP ABAP Developer
HUGO BOSS AG
Engineering Lead - SAP Core Development
Sales, Logistics & Supply Chain
Technical leadership and operational implementation in a highly complex SAP Core landscape, with responsibility for architecture, engineering governance and direct ABAP development.
- Technical leadership of distributed SAP development teams with 50+ internal and external developers
- Architecture and design responsibility for business-critical SAP Core components
- Hands-on ABAP development in business-critical SAP ECC and S/4HANA systems
- Modernization, refactoring and performance optimization of existing ABAP logic
- Establishment of Clean Code principles, coding guidelines and structured code reviews
IMPACT ACHIEVED:
- Stabilization and scaling of the SAP development organization while increasing code quality and delivery reliability
- Created a technically sound foundation for the S/4HANA transformation
Technical Project Lead / SAP ABAP Developer
HUGO BOSS AG
Technical Project Lead - SAP CAR, Omnichannel & Code Quality
Technical project leadership in complex SAP retail landscapes, focusing on SAP CAR, omnichannel processes and sustainable improvement of code quality.
- Technical project leadership in the SAP CAR and omnichannel environment
- Introduction and establishment of Clean Code principles in development teams
- Establishment of unit testing and Test-Driven Development (TDD)
- Structured code reviews to ensure quality and maintainability
- Coaching developers in refactoring and sustainable code architecture
- Technical coordination with architecture, basis and adjacent systems
IMPACT ACHIEVED:
- Significantly improved code quality and long-term maintainability of the ABAP codebase
- Established modern engineering standards as a foundation for future scaling
Software Engineer / SAP ABAP Developer
HUGO BOSS AG
Software Engineer - SAP Retail & Sales (ABAP)
Hands-on SAP ABAP development in sales-driven retail processes in a productive international SAP retail environment.
- SAP ABAP development in end-to-end sales processes (Order-to-Cash)
- Implementation and enhancement of stable SAP backend functionality
- Close collaboration with business departments to translate requirements into technical solutions
- Early involvement in solution design and technical architecture decisions
IMPACT ACHIEVED:
- Built a strong foundation of SAP Retail and sales domain expertise for the long term
- Delivered stable, maintainable ABAP solutions in a productive retail environment
Industry experience
See where this freelancer has spent most of their professional time.
Experienced in Retail and Fashion.
Business area experience
See which departments and functions this freelancer has contributed to most.
Experienced in Information Technology, Product Development, and Project Management.
Summary
Senior SAP ABAP Developer and Solution Architect with 16+ years of enterprise software engineering experience in SAP S/4HANA, SAP Core, SAP Retail and SAP Customer Activity Repository (SAP CAR), including POS Data Transfer and Audit (POSDTA). Most recently responsible for a large-scale S/4HANA custom solution replacing required retail/POS standard functionality. Uses a production-proven AI-native engineering model in which AI agents generate implementation and test code, while architecture, quality, SAP validation and release responsibility consistently remain Human-in-the-Loop. Combines deep hands-on ABAP expertise with architectural responsibility and many years of technical leadership of distributed engineering teams.
- Productive use of an AI-native engineering model in a real enterprise SAP project
- Extensive modular custom solution with several hundred SAP development objects
- High maintainability and testability through modular architecture, automated tests and structured reviews
- Replacement of required standard functionality to reduce recurring licensing and operating costs
- Stabilization and scaling of the SAP development organization while increasing code quality and delivery reliability
- Created a technically sound foundation for the S/4HANA transformation
- Significantly improved code quality and long-term maintainability of the ABAP codebase
- Established modern engineering standards as a foundation for future scaling
- Built a strong foundation of SAP Retail and sales domain expertise for the long term
- Delivered stable, maintainable ABAP solutions in a productive retail environment
- 16+ years of experience in international fashion & retail organizations at enterprise level
- Deep understanding of SAP-driven core processes in omnichannel retail environments
- Experience with highly integrated sales, logistics and supply chain processes
- Stabilization and further development of complex retail system landscapes
AI-native engineering is the differentiator; deep SAP ABAP and S/4HANA expertise provides the enterprise foundation. Suitable for hands-on senior ABAP roles as well as Technical Lead, Solution Architecture and AI-native engineering responsibility.
Skills
Core Competencies
- Sap Abap
- Sap S/4hana
- Abap Oo
- Solution Architecture
- Sap Retail
- Sap Car/Posdta
- Sap Ecc
- Cds Views Amdp
- Odata / Gateway
- Ale / Idocs
- Enterprise Integration
Ai-Native Engineering
- Generative Ai
- Ai Agents
- Ai-Native Development
- Design Authority
- Agentic Development
- Ai Code Review
- Human-In-The-Loop
- Git
Engineering Quality
- Clean Core
- Clean Code Abap
- Abap Unit
- Tdd
- Code Reviews
- Refactoring
- Performance Optimization
Leadership
- Engineering Lead
- Technical Lead
- Solution Architect
- Enterprise Architecture
- Distributed Teams
- Delivery Responsibility
- Engineering Governance
Sap Domains
- Sap Retail
- Sap Car/Posdta
- Sap Sd / Billing Order-To-Cash
- Sales
- Logistics
- Supply Chain
Engineering
- S/4hana Transformation
- Code Reviews
- Refactoring
- Performance Engineering
- Unit Testing
- Tdd
- Clean Core
- Git
Working Model
- Hands-On Sap Engineering
- Independent Remote Delivery
- Architecture And Technical Responsibility
- Ai-Native Development Governance
Languages
Statistics
Experience
Global experience
Expertise
Frequently asked questions
Have questions? Find more information here.
Sebastian is based in Zeulenroda-Triebes, Germany and can operate in on-site, hybrid, and remote work models.
Sebastian speaks the following languages: German (Native), English (Advanced).
Sebastian has at least 17 years of experience. During this time, Sebastian has worked in at least 4 different roles and for 2 different companies. The average length of individual experience is 4 years and 2 months. Note that Sebastian may not have shared all experience and actually has more experience.
Based on recent experience, Sebastian would be well-suited for roles such as: Senior SAP ABAP Developer / Solution Architect, Engineering Lead / Senior SAP ABAP Developer, Technical Project Lead / SAP ABAP Developer.
Sebastian's most recent position is Senior SAP ABAP Developer / Solution Architect at Confidential Client.
In recent years, Sebastian has worked for Confidential Client and HUGO BOSS AG.
Sebastian is most experienced in industries like Retail and Fashion.
Sebastian is most experienced in business areas like Information Technology, Product Development, and Project Management.
Sebastian has recently worked in industries like Retail and Fashion.
Sebastian has recently worked in business areas like Information Technology and Product Development.
Sebastian is immediately available full-time for suitable projects.
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Calculated based on our freelancers’ daily rates as of 25 Oct 2026. Actual rates may vary depending on seniority level, experience, skill specialization, project complexity, and engagement length.
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