E-Invoicing Experts in Germany

• Defined S/4HANA finance solution architecture and led full project lifecycle — Blueprint through Hypercare — for global rollout.
• Designed global finance templates and COPA characteristics, harmonizing financial reporting across business units.
• Implemented role-based authorizations, SOD controls, and master data governance; managed provisioning and training for 200+ users.
• Coordinated cross-module integrations (MM, SD, PP) and third-party systems (Salesforce, SAP DRC, E-Invoicing), reducing month-end close from 5 days to 2 days.
• Prepared functional specifications, supported ABAP development, and drove problem management practices that reduced recurring incidents.

• DTO class generator: In-house development of a tool for the automatic generation of classes, functions, and methods for use in .NET Core projects based on SAP Business One Service Layer metadata
• E-invoice import add-on: Development of a SAP Business One add-on / coresuite module for the automated import of ZUGFeRD e-invoices as incoming invoices – with configurable mapping to flexibly control the import logic across four mapping types (DIRECT, SQL, FIXED, EXPR). The add-on is available as a licensed product for SAP Business One customers.

Stack: SAP Business One, SAP Business One Service Layer, coresuite Country Package, C#

• Consolidation
• Mergers
• Law firm chart of accounts / cost centers
• Preparation of annual financial statements
• Digital process development and optimization of the accounting/closing and reporting area
• Optimization of the DATEV software environment

• Responsible for the concept, planning, and implementation of the product development of GetMyInvoices 2.0 and the subcomponent InvoiceRails
• Independent work on all aspects of the project, including concept, specification in tickets, and coordination of developers
• Creation, management, and prioritization of tickets to ensure all tasks are completed on time and with high quality
• Carrying out and/or coordinating tests and ensuring the proper implementation of the developed features and functionalities
• Close collaboration with developers to clarify technical requirements and ensure the implementations match the specifications
• Regular reporting on project progress and documentation of key decisions, changes, and risks
• Taking on the subject matter lead for all topics around e-invoicing and Peppol, especially in relation to the InvoiceRails component
• Internal consulting and knowledge sharing on e-invoicing and Peppol for other teams and departments
• Tracking market trends and new developments in e-invoicing and Peppol to continuously adapt the product strategy
• Ensuring the long-term scalability and flexibility of the products for future technical and regulatory changes in the e-invoicing area

• Replacement and renewal of the existing client PCs with an upgrade to Windows 11 and mobile workstations with laptops and docking stations
• Introduction of Office365 with OneDrive use
• Introduction of e-invoicing with DATEV accounting software
• Revision of the standard office applications in daily use
• File storage in SharePoint instead of local data storage
• New authorization structure for users
• Use of Microsoft accounts to synchronize profiles
• Reorganization of the document scanning process with storage in SharePoint
• New backup concept in addition to the Microsoft cloud solution
• Introduction of new data structures: review and separation of data into active, inactive, private, business
• Simplification of processes
• Increased data security and improved security
• Permanent data availability at all internal and external workplaces

Design and implementation of a compact ERP, CRM, accounting, and production-planning platform for a German food manufacturer. The system replaces Rechnung11, self-built Excel sheets, and manual processes for fewer than 10 internal users.

• Designed and implemented the full platform architecture as sole architect and developer.
• Built modules for customer management, B2B order handling, invoicing, production planning, and accounting support.
• Implemented DATEV export, ZUGFeRD/XRechnung e-invoicing, FinTS bank statement synchronization, and GoBD audit trail concepts.
• Used AI-supported workflows for prototyping, test support, and implementation acceleration while retaining full architecture, review, testing strategy, and technical ownership.

Technology: Java 23, Spring Boot 3, Spring Data JPA, Spring Security, Vue 3, TypeScript, PostgreSQL, Flyway, REST, OpenAPI, JWT, TOTP, RBAC, DATEV, FinTS, ZUGFeRD, XRechnung, GoBD, JUnit, Mockito, Testcontainers, Playwright, Docker, GitLab CI/CD

• Development of software and system support for RPG development.
• Development, optimization and maintenance of programs in RPG (RPG II to ILE Free Format).
• Performing integration tasks, data management as well as applying and managing system updates.
• User support and training to ensure smooth system operation.

• Concept and full-stack development of an app for parking space booking & management (Hahn Airport)
• From requirements to implementation and deployment; AI-supported development (Claude Code)

• The main goal of the project was to link the ECC system to the French e-invoicing network. This includes ensuring compliance with national e-invoicing regulations and achieving e-reporting readiness for the digital transfer of transaction data.

• Standardization of order management processes to achieve the required data quality and consistency.

• Ensuring correct VAT determination through targeted developments (customizing and, if necessary, ABAP) in the SAP SD module to comply with EU tax regulations.

• Design and configuration of the down payment process (Down Payments) in the SAP ECC system.

SAP S/4HANA Implementation (Greenfield)

• SAP Finance Reporting
• VAT Reporting
• Foreign Plants
• Tax Calculation for SD/MM
• Z4/Z5 Reports
• Intrastat
• SAP DRC (E-Invoicing)

System: SAP

Industry: Manufacturing

Team: 10

• Lead SAP Controlling, Product Costing and Material Ledger activities across multiple legal entities, improving standard-costing consistency, inventory valuation and month-end financial reporting.
• Contributed to a 30% reduction in the overall financial closing cycle by coordinating SAP Finance, Controlling, Material Ledger and plant-closing activities against a structured month-end calendar.
• Maintain 99.5% SLA adherence while resolving complex Level 2 and Level 3 incidents across Product Costing, Cost Center Accounting, Material Ledger, Actual Costing, WIP, variance calculation and production-order settlement.
• Execute and validate individual and mass standard-cost estimates using CK11N and CK40N, ensuring accurate costing based on current BOMs, routings, activity prices, purchasing conditions and overhead structures.
• Improved product-costing accuracy by identifying and correcting inconsistencies across material-master costing views, activity types, work centres, BOMs, routings and purchasing data.
• Reduced month-end delays by resolving missing cost estimates, incomplete settlement rules, incorrect activity allocations, variance-calculation errors and production-order settlement failures.
• Reconcile production-order costs, inventory values, purchase-price differences, work in process, production variances and settlement postings across SAP Controlling, Material Ledger and General Ledger.
• Execute Material Ledger and Actual Costing close activities, including price determination, purchase-price-difference allocation and periodic unit-price validation.
• Analyse manufacturing-cost variances across raw materials, labour, machine activity, subcontracting, production usage and overhead costs, enabling business controllers to identify root causes and cost-reduction opportunities.
• Configure and support costing variants, valuation variants, quantity structures, cost-component structures, overhead-costing sheets and automatic account-determination settings.
• Coordinate annual standard-cost planning, costing runs and standard-price releases with Finance, Procurement, Production and plant-controlling teams.
• Improved indirect-cost visibility through cost-center planning, activity-price calculations, assessments, distributions and cost-allocation cycles.
• Support profitability reporting through Account-Based CO-PA, enabling analysis by product, customer, market, company code and profit center.
• Developed reconciliation controls, standard operating procedures and costing reports that improved financial governance, closing accuracy and audit readiness.
• Facilitate workshops and knowledge-transfer sessions covering standard costing, Material Ledger, WIP, production variances and production-order settlement.

• Support for an SAP S/4HANA migration
• Adjustments and bug fixes in SAP CATS
• Technical stabilization of existing developments
• Code analysis and cleanup of custom ABAP developments

• Service owner of the receivables management platform Ikarus
• Management and coordination of external 1st-level service providers
• Team leadership and building ITIL-compliant support structures
• Managing the handover to 3rd-level support (internal & external, incl. vendor/development)
• Stakeholder management between the business unit, IT, and external partners
• Jira ticket automations and maintenance of Confluence documentation

Task

• Further development of a new ERP system with Blazor
• Creation of e-invoices in the XRechnung and ZUGFeRD formats
• UI/UX design Client-server system
• Windows 11 Technology
• Microsoft .NET 9, Git, Azure DevOps, ASP.NET, MSSQL, Blazor Programming languages
• C#, MVVM Development tools
• Microsoft Visual Studio .NET 2022 Database
• MSSQL Industry
• Other