08/20/2026 updated
100 % available
Senior SAP ABAP Developer | S/4HANA, BTP, RAP, OData & Integration
Shantou, China
Only remote
B.S. in Computer Science & Information TechnologyAbout me
Senior SAP engineer (15+ yrs) passionate about clean architectures and complex problem-solving. I bridge classic ECC/R3 with modern S/4HANA, BTP, and GenAI. Clients trust my pragmatic delivery, high code quality, and clear technical communication. Autonomous, reliable, and 100% remote.
Java (Programming Language)SAP Web DynproJava Development KitSAP ERPSAP ABAPSAP COSAP Customizing/KonfigurationSAP HANASAP ImplementationSAP R/3SAP PSSAP SDSystems IntegrationSAP DevelopmentSAP AIF
SAP BTP & Cloud-Native Development
Expertise in SAP BTP (ABAP Cloud Environment), RAP Managed and Unmanaged Scenarios, CDS Views, OData V2/V4 service modeling with Draft Handling, and Clean Core Methodology. Development of complex procurement approval and supplier collaboration modules on SAP BTP.
Enterprise System Integration
Mastery of complex heterogeneous system integration including SAP PO 7.50 AAE, SPROXY (Client Proxy), IDoc/EDI, RESTful API consumption and publishing, JSON processing via XCO library, Base64 handling, and high-volume batch optimizations. Design and implementation of real-time, low-latency, high-concurrency bi-directional integration pipelines.
Classic ABAP Engineering
Deep proficiency in OO ALV (CL_GUI_ALV_GRID), Dynpro Screen Programming, Enhancement Framework (BAdI, User-Exits, Enhancement-Points), BAPI, RFC, IDoc/EDI, SAP Workflow, SmartForms, and Adobe Forms across FICO, MM, SD, PS, HR/HCM, and MDG modules.
Master Data Governance (MDG)
Implementation of MDG-M (Material) and MDG-S (Supplier/BP) governance pipelines, BRF+ business rules (Validations and Derivations), Floorplan Manager (FPM) UI enhancements, and Change Request Workflows.
Generative AI Integration
End-to-end integration between SAP BTP and Generative AI platforms (Google Gemini Vision / OpenAI), automating OCR document recognition, extraction, and direct SAP financial posting. Custom ABAP processing engines to parse JSON payloads and trigger document creation/clearing in S/4HANA.
HCM/Payroll & Workday Integration
Bi-directional interface integration between Workday and SAP HCM across multiple countries. Handling of 15+ Infotypes with automated file pre-checks, wage type mapping, batch postings, and alert notifications. Payroll Driver and Cluster RX (PAYRESULT) data extraction, validation, and posting.
Fiori & OData Development
Development of OData services for mobile Worklist apps and Time Confirmation apps, supporting dynamic list outputs, single/batch document generation, and bi-directional work order status synchronization. Optimization of complex Worklist SQL queries and end-to-end Error Log and Change Log audit tracking.
WMS & EDI Integrations
Building end-to-end WMS interface streams (Material, Barcode, GR/GI confirmation) and auto-DN generation. Spearheading IDoc/EDI inbound/outbound flows (DN, GR, Logistics Invoice Verification) and HR/OA interfaces automating staff labor cost allocations.
Functional Domain Expertise
Broad functional coverage across Financial Accounting and Controlling (FICO), Materials Management (MM), Sales and Distribution (SD), Human Capital Management and Payroll (HR/HCM/Payroll), Project Systems (PS), and Master Data Governance (MDG).
Expertise in SAP BTP (ABAP Cloud Environment), RAP Managed and Unmanaged Scenarios, CDS Views, OData V2/V4 service modeling with Draft Handling, and Clean Core Methodology. Development of complex procurement approval and supplier collaboration modules on SAP BTP.
Enterprise System Integration
Mastery of complex heterogeneous system integration including SAP PO 7.50 AAE, SPROXY (Client Proxy), IDoc/EDI, RESTful API consumption and publishing, JSON processing via XCO library, Base64 handling, and high-volume batch optimizations. Design and implementation of real-time, low-latency, high-concurrency bi-directional integration pipelines.
Classic ABAP Engineering
Deep proficiency in OO ALV (CL_GUI_ALV_GRID), Dynpro Screen Programming, Enhancement Framework (BAdI, User-Exits, Enhancement-Points), BAPI, RFC, IDoc/EDI, SAP Workflow, SmartForms, and Adobe Forms across FICO, MM, SD, PS, HR/HCM, and MDG modules.
Master Data Governance (MDG)
Implementation of MDG-M (Material) and MDG-S (Supplier/BP) governance pipelines, BRF+ business rules (Validations and Derivations), Floorplan Manager (FPM) UI enhancements, and Change Request Workflows.
Generative AI Integration
End-to-end integration between SAP BTP and Generative AI platforms (Google Gemini Vision / OpenAI), automating OCR document recognition, extraction, and direct SAP financial posting. Custom ABAP processing engines to parse JSON payloads and trigger document creation/clearing in S/4HANA.
HCM/Payroll & Workday Integration
Bi-directional interface integration between Workday and SAP HCM across multiple countries. Handling of 15+ Infotypes with automated file pre-checks, wage type mapping, batch postings, and alert notifications. Payroll Driver and Cluster RX (PAYRESULT) data extraction, validation, and posting.
Fiori & OData Development
Development of OData services for mobile Worklist apps and Time Confirmation apps, supporting dynamic list outputs, single/batch document generation, and bi-directional work order status synchronization. Optimization of complex Worklist SQL queries and end-to-end Error Log and Change Log audit tracking.
WMS & EDI Integrations
Building end-to-end WMS interface streams (Material, Barcode, GR/GI confirmation) and auto-DN generation. Spearheading IDoc/EDI inbound/outbound flows (DN, GR, Logistics Invoice Verification) and HR/OA interfaces automating staff labor cost allocations.
Functional Domain Expertise
Broad functional coverage across Financial Accounting and Controlling (FICO), Materials Management (MM), Sales and Distribution (SD), Human Capital Management and Payroll (HR/HCM/Payroll), Project Systems (PS), and Master Data Governance (MDG).
Experience
Professional experience10+ years
Freelancer since2024
Languages
ChineseNative speakerEnglishFluent
Project history
Designed and implemented a real-time, low-latency, high-concurrency bi-directional integration pipeline connecting core S/4HANA business events with external cloud SaaS and microservices following an S/4HANA upgrade. Architected end-to-end Client Proxy pipelines (SPROXY), built SAP PO 7.50 integration pipeline with standard Software Components and namespaces in ESR, implemented complex Message Mappings with custom Java UDFs, and conducted full end-to-end integration stress tests.
Rebuilt legacy custom extensions on SAP BTP ABAP Environment following an ECC to S/4HANA Public Cloud migration adhering strictly to the Clean Core strategy. Architected RAP Managed Scenarios for procurement approval and supplier collaboration modules, built multi-tier CDS Views exposed via OData V4 services for Fiori front-ends, implemented Draft Handling for large-scale purchase requisition entries, and ensured 100% compliance with ABAP Cloud guidelines.
Led SAP BTP cloud-native development (RAP/OData), enterprise Generative AI integrations for finance, Fiori mobility, and reusable developer toolkits. Connected Google Gemini Vision API / OpenAI via SAP BTP Destination service for high-precision extraction of unstructured invoices. Developed standardized ABAP Cloud toolkit with JSON processing engines, configured BTP XSUAA fine-grained role-based access control, developed OData services for mobile Worklist apps and Time Confirmation apps for Hong Kong EMSD Fiori Mobility Phase II.