Sebastian Gesiarz, Developer in Wrocław, Poland
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Sebastian Gesiarz

Verified Expert  in Engineering

SAP Consultant and Developer

Wrocław, Poland
Toptal Member Since
November 29, 2023

Sebastian has 9+ years of SAP, BI, and data engineering experience. Adept at gathering and analyzing requirements, he crafts data warehouse architectures with an exceptional user experience and state-of-the-art reporting. He identifies optimal solutions—examining business processes with a clear separation between semantic and data modeling. Sebastian also expertly manages product owners' expectations, plans project backlogs, and delivers software and documentation that adhere to Agile practices.


Tenthpin Management Consultants
SAP Datasphere, SAP Analytics Cloud (SAC)
Hilti North America
SAP Datasphere, SAP Analytics Cloud (SAC), SAP, SAP BW/4HANA, ABAP...
SAP BW/4HANA, SAP Profitability and Performance Management (PaPM), Snowflake...




Preferred Environment

SAP HANA, SAP HANA Cloud, SAP, SAP Datasphere, SAP BW/4HANA, SAP HANA SQLScript, ABAP, SAP Analytics Cloud (SAC), Python

The most amazing... I've developed predicted which machine installed by the customer would likely break and estimated the potential repair costs.

Work Experience

Senior SAP Datasphere and SAC Planning Consultant

2022 - PRESENT
Tenthpin Management Consultants
  • Built an inventory management data model in SAP Datasphere and the SAP Analytics Cloud (SAC) front end using S/4HANA, Datasphere, and SAC development best practices.
  • Designed and developed two SAC planning applications using flat files and SAP Datasphere as the source. One is to plan and simulate the production process improvements, and the second is to plan supply chain costs.
  • Supported the volume planning project and designed and developed the SAC to SAP Business Warehouse (BW) write-back capability.
Technologies: SAP Datasphere, SAP Analytics Cloud (SAC)

Senior SAP Datasphere and SAC Consultant

2022 - 2022
Hilti North America
  • Designed, built, and configured all components that interacted with SAP Datasphere, including BW/4HANA, the cloud connector, SAC, and the data provisioning agent. I built proofs of concepts and created SAP Datasphere development guidelines.
  • Built a performance dashboard with custom data flow for online analytical processing statistics—providing valuable insights into system performance and allowing for the optimization of several SAC applications and SAP Business Explorer (BEx) queries.
  • Improved system performance and reduced downtime risk by introducing them to the technical monitoring cockpit tool to prove that increasing parallel SAC sessions would fit within the current landscape configuration.
  • Created an ABAP service that consumed the SAC API metadata and posted it to BW/4HANA. This integration allowed seamless data transfer between the two systems and provided valuable insights into data analytics and reporting.
Technologies: SAP Datasphere, SAP Analytics Cloud (SAC), SAP, SAP BW/4HANA, ABAP, SAP HANA SQLScript

Senior SAP Analytics Consultant

2021 - 2022
  • Designed and built a flagship project for profitability analysis using SAP Profitability and Performance Management (PaPM), BW/4HANA, and SAC.
  • Optimized data storage and retrieval in BW/4HANA by implementing data tiering optimization (DTO). I also revised existing models by adding new BW/4HANA features—ensuring the project was futureproofed and aligned with industry best practices.
  • Advised clients strategically on the direction of the SAP data warehouse and HANA extended application services advanced model (XSA) migration, helping them stay up-to-date with the latest technologies and trends.
  • Implemented HANA real-time data acquisition from SharePoint in Office 365, providing clients instant access to critical business data.
Technologies: SAP BW/4HANA, SAP Profitability and Performance Management (PaPM), Snowflake, ABAP, SAP HANA SQLScript

SAP Planning and Analytics Consultant

2021 - 2021
Delivery Hero
  • Designed and implemented a full-time equivalent forecasting application that helped clients accurately predict staffing needs. I created a custom alert broadcasting service that notified cost center owners when they ran under budget.
  • Simplified the navigation process of the activity and revenue planning application. I used the SAC planning calendar, which resulted in a more intuitive and user-friendly interface.
  • Created a Push API that enabled users to input and validate CSV data directly into SAC planning models, improving the accuracy and efficiency of the planning process.
  • Broadened the use of BW/4HANA mixed scenarios, ABAP-managed database procedures (AMDP), and data flow objects to improve system performance and scalability, ensuring the system was optimized for future growth.
  • Helped set up an Agile project framework using Jira, Confluence, and Smartsheet, allowing streamlined collaboration and efficient project management.
Technologies: SAP BW/4HANA, SAP Analytics Cloud (SAC), ABAP, SAP HANA SQLScript, Agile

SAP HANA Analytics Consultant

2019 - 2020
ASML Holding
  • Enabled the cost analysis of non-quality products and empowered business line reporting by event allocation.
  • Prepared SAP HANA extended application services (XS) classic models for HANA Cloud and XSA migration.
  • Created and implemented modular, parametrized, and reusable HANA virtual data models.
  • Devised and developed a material design trusted data set for SAP HANA Cloud.
  • Provided an architecture and implemented on-the-fly repair rates calculation using time-dependent median and material predecessor trail.
  • Developed a virtual robot testing framework environment using microservices and scalable containers.
  • Collected event data using Prometheus gauges and visualized it in Grafana.
  • Designed and deployed a row-level secure machine data authorization concept.
  • Automated tests using the XSUnit library. Improved HANA SQL data warehouse performance by pinpointing bottlenecks and optimizing models, consuming the data through HANA smart data access and the SAP Landscape Transformation Replication Server (SLT).
Technologies: SAP HANA Cloud, Data Warehousing, Data Engineering, Python 3, Docker, Kubernetes, Grafana, Spotfire, SAP HANA Enterprise Cloud (HEC)

SAP BW and BPC Consultant

2018 - 2019
Merck & Co.
  • Deployed core SAP Business Planning and Consolidation (BPC)-based manual interfaces and served as a subject matter expert for the cloud for finance project.
  • Created a framework for intercompany profit elimination in profit and loss, balance sheet, and sales. Enabled users to interact with the data warehouse by using the BPC front end and business process flows to correct, upload, and consolidate data.
  • Streamlined business processes using SAP BI integrated planning (IP). Implemented an allocation engine allowing users to distribute sales and profits across legal entities.
  • Deployed an on-the-fly balance sheet shift and reporting layer virtual data release model. Designed, implemented, and automated data reprocessing and self-healing engines.
  • Promoted and led the SAP BW on HANA mixed scenarios architecture.
Technologies: SAP BW on HANA, SAP BI Integrated Planning (BI-IP), ABAP, SAP HANA, SAP HANA SQLScript, SAP Business Planning and Consolidation (BPC)

SAP BW and BI-IP Developer

2017 - 2018
  • Enabled stock forecasting and turnover based on near-real-time goods movement.
  • Set the ground and created the first interfaces for operational data provisioning and delta queue (ODP/ODQ).
  • Allowed comparative analysis by blending stock data with sales and rolling forecasts. Provided sets of reports for inventory and SAP CO profitability analysis. Empowered the user by delivering on-the-fly unit of measurement conversion.
  • Developed KPIs using S/4HANA embedded analytics. Provided analysis of alternatives for BW workspaces and HANA mixed scenarios. Implemented data flows based on the SLT data extractors.
  • Delivered a proof of concept for SAP Fiori applications based on S/4HANA core data service views and the business object processing framework.
Technologies: SAP BW on HANA, SAP Business Planning and Consolidation (BPC), Apache FOP, SAP Lumira

SAP BW and BI Consultant

2014 - 2017
AB Volvo
  • Tuned the data model performance and maintained housekeeping activities before and after the HANA migration.
  • Implemented the new authorization concept across two business warehouses migrating to HANA.
  • Developed the data flows for supply chain management and material supersession.
  • Enabled the user to report missing orders and invoices directly into SAP BW.
  • Migrated BW business planning and simulation to BI-IP.
  • Created dashboards in SAP Analysis for Microsoft Office (AFO) using a mix of Visual Basic for Applications and SAP APIs. Developed new KPIs for the sales, marketing, and technology departments and provided ad hoc reports using SAP Lumira.
Technologies: SAP BW on HANA, ABAP, SAP Lumira, SAP AfO

Interface to Connect Office 365 with SAP HANA Enterprise
Extracting the flat files from Microsoft SharePoint to SAP BW/4HANA.

• Load the flat files from SharePoint to BW/4HANA
• Store the flat file changelog and snapshots in BW/4HANA
• Enhance existing BW models with flat file data managed in SharePoint

Interface to Consume SAC OData Service in BW/4HANA
Consuming SAC APIs in ABAP and posting the result to the BW advanced DataStore object.

• Store changelog for SAC metadata
• Enhance existing BW models with SAC metadata
• Consume SAC APIs through ABAP using OAuth 2.0
• Use token authentification
2012 - 2018

Master's Degree in Business Intelligence

Wrocław University of Economics and Business - Wrocław, Poland


Grafana, Spotfire


Business Intelligence (BI), Agile, Data Science


ABAP, Python, Snowflake, Python 3, R, PHP, Java




SAP HANA, Docker, Kubernetes


SAP Datasphere, SAP BW/4HANA, SAP Analytics Cloud (SAC), Data Warehousing, Data Engineering, SAP BW on HANA, SAP BI Integrated Planning (BI-IP), Apache FOP, SAP Lumira, SAP AfO, SAP Business Intelligence (BI), SAP HANA Enterprise Cloud (HEC), SAP Profitability and Performance Management (PaPM), Big Data Architecture, Decision Modeling, Data Mining, IT Project Management, OData, Business Information Systems, SAP HANA Cloud, SAP, SAP Business Planning and Consolidation (BPC)

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