Jakub Gulewski - MSSQL Backend / Data Engineer Specialist

Q: Where is Jakub based?

Jakub is based in Toruń, Poland .

Q: What languages does Jakub speak?

Jakub speaks the following languages: Polish (Native), English (Advanced), German (Intermediate) .

Q: How many years of experience does Jakub have?

Jakub has at least 14 years of experience. During this time, Jakub has worked in at least 16 different roles and for 25 different companies . The average length of individual experience is 1 year and 7 months . Note that Jakub may not have shared all experience and actually has more experience.

Q: What is Jakub's latest experience?

Jakub's most recent position is MSSQL Backend / Data Engineer Specialist at Schneider Electric .

Q: What companies has Jakub worked for in recent years?

In recent years, Jakub has worked for Schneider Electric , New Work SE , Credit Suisse , Grundfos , and Zurich Insurance .

Q: Which industries is Jakub most experienced in?

Jakub is most experienced in industries like Information Technology , Retail , and Fashion . Jakub also has some experience in Banking and Finance , Energy , and Insurance .

Q: Which business areas is Jakub most experienced in?

Jakub is most experienced in business areas like Business Intelligence , Information Technology , and Quality Assurance . Jakub also has some experience in Accounting , Finance , and Project Management .

Q: Which industries has Jakub worked in recently?

Jakub has recently worked in industries like Energy , Banking and Finance , and Insurance .

Q: Which business areas has Jakub worked in recently?

Jakub has recently worked in business areas like Business Intelligence , Information Technology , and Project Management .

Recommended expert

Toruń, Poland

Check rate

Experience

Apr 2024 - Jun 2025

1 year 3 months

Warsaw, Poland

MSSQL Backend / Data Engineer Specialist

Schneider Electric

Joined the team to evaluate the existing backend architectural landscape and processes with a focus on future improvements in SQL and ETL for the data warehouse.
Acted as data architect and senior SQL developer, investigating possible improvements in the data model and code.
Simplified maintenance and added modularity by unifying custom logging, process audits, custom monitoring, and reorganizing code.
Prepared a roadmap for CI/CD, code review, optimization, and standardization of code and processes.
Collaborated closely with the team on user management and data security, and with various departments and owners throughout the product lifecycle.
Developed and supported business-as-usual processes.
Tech stack: MSSQL 2019, SSIS 2019, Amazon AWS Redshift, Aurora, S3, Tableau, Jira, Confluence.

Jan 2023 - Mar 2023

3 months

Frankfurt, Germany

Data Modelling Expert

New Work SE

Supported the client with data architecture, data modelling, BAU support, and improvements to existing BI processes.
Built and maintained OLAP data models and data marts for a data warehouse.
Developed, optimized, and maintained SQL code, transformations, and integration with Tableau reports.
Collaborated with various departments and owners throughout the product lifecycle.
Tech stack: Exasol, DBSchema, DBeaver, Tableau Desktop, Tableau Prep.

Feb 2022 - Dec 2022

11 months

Zürich, Switzerland

MSSQL Backend Specialist / Consultant

Credit Suisse

Supported and enhanced existing automated ETL/SQL solutions.
Designed and implemented OLAP data models (logical, physical, Kimball).
Created and maintained T-SQL code and processes with a focus on optimization, orchestration, index strategy, row- and column-level security.
Developed SSRS reports and maintained a metadata-driven ETL solution based on T-SQL, SSIS, and .NET.
Evaluated and enhanced the current solution with new features.
Built SSIS/T-SQL data integration between the data warehouse and data marts.
Automated BI processes including error handling, process auditing, logging, and reporting.
Tech stack: Microsoft SQL Server 2019, SSIS, SSRS, SSAS, T-SQL, Visual Studio 2019, Git, Agile, PowerShell, Oracle, Jira, Confluence.

Feb 2022 - Feb 2022

1 month

Frankfurt, Germany

Business Intelligence Specialist

Grundfos

Delivered reports and dashboards for project management in Power BI.
Collaborated closely with the business owner on overall implementation.
Designed and developed a snowflake-schema data model.
Developed DAX calculations for visuals, implemented row-level security, and wrote M-language code to process external data.
Tech stack: Power BI, DAX, Power Query.

Jun 2021 - Oct 2021

5 months

Frankfurt, Germany

MSSQL Backend / Data Engineer Specialist

Zurich Insurance

Improved performance of data integration and Power BI dashboards and reports.
Reviewed current processes, collected requirements, performed gap analysis, and recommended redesign of data architecture focusing on optimization and orchestration.
Built high-performance visuals for large data volumes with row-level security and smooth user experience.
Designed and implemented a new star/snowflake data model in Power BI with a new T-SQL layer.
Increased report responsiveness by simplifying complex DAX calculations, applying T-SQL optimizations, and automating processes.
Tech stack: SQL Server 2019, Power BI, Azure, Azure Analysis Services, DAX, Power Query, Azure SQL, Agile.

Jan 2021 - Feb 2021

2 months

Frankfurt, Germany

Data Engineer / Business Intelligence Specialist

BASF

Led the Power BI team and collaborated with senior management on new reporting solutions and data architecture.
Gathered requirements, conducted testing, and provided guidance on best practices, methodologies, and code optimization to meet SLA timelines.
Designed streamlined and efficient data delivery processes with cross-functional teams.
Migrated reports from Tableau to Power BI, developing DAX calculations, Power Query transformations, data models, and row-level security.
Partnered with data analysts to validate requirements, verify data accuracy, and test end-to-end processes.
Developed advanced visualizations including geo-referencing, mapping, nested filters, and longitudinal analysis.
Tech stack: Power BI, Azure, DAX, Power Query, Tableau, Excel.

May 2019 - Dec 2019

8 months

Frankfurt, Germany

MSSQL Backend Specialist / Consultant

Dentsply Sirona

Delivered enhanced ETL feed processes for Salesforce CRM by analyzing existing workflows, identifying gaps, and designing a new data architecture.
Designed and developed incremental ETL and SQL processes with robust error handling and simplified maintenance.
Implemented automated, self-healing data feeds between the data warehouse and Salesforce CRM.
Optimized solution for scalability, modularity, error handling, process auditing, and ease of maintenance.
Incorporated comprehensive error logging, data validation, and process auditing for low latency and high parallelism.
Built a data warehouse process with incremental loads and Change Data Capture.
Tech stack: MS SQL 2017, SSIS, DBAMP, Azure PaaS, Data Vault, VSTS, MS Build, Salesforce.

Jan 2019 - Feb 2019

2 months

London, United Kingdom

MSSQL Backend Specialist / Consultant

Global Brand Group

Investigated and optimized CRM-to-DWH data integration, reviewing processes and business rules to advise on rebuilding the ETL framework.
Designed and delivered a proof of concept for a new data architecture integrating Dynamics AX 2012 with the data warehouse and reporting layer.
Redesigned architecture and processes to enhance performance, data availability, and reliability.
Developed a PoC ETL solution using SSIS and SQL Server DWH with continuous, incremental data loading, orchestration, self-awareness, and self-healing capabilities.
Implemented logging and auditing to strengthen transparency and governance.
Designed new Power BI data models (T-SQL based and Tabular) optimized for scalability, modularity, and maintainability.
Introduced row-level security for secure, role-based access to visuals and reports.
Tech stack: MS SQL 2014, SSIS, SSAS, SSRS, DAX, Power Query, Data Vault, AX 2012, Azure PaaS, VSTS, Jira, Confluence.

Feb 2018 - Jul 2018

6 months

Frankfurt, Germany

MSSQL Developer

Deutsche Bank

Collaborated with the front-end team on an internal application for monitoring and analysing bank security, responsible for data architecture and SQL development.
Partnered with cross-functional teams to build business knowledge, perform gap analysis, and create detailed process documentation.
Planned and executed data architecture and modelling (conceptual and physical), developed new T-SQL objects, and implemented database user security.
Designed and implemented logging and auditing processes, integrating SSIS for ETL and reporting to support data workflows and visualizations.
Tech stack: MS SQL 2012, SSIS 2012, GitHub, VSTS, Jira, Confluence.

Jan 2018 - Feb 2018

2 months

London, United Kingdom

MSSQL Backend Specialist / Consultant

HCA Healthcare UK

Supported business operations through administration, BAU tasks, and development, collaborating with business owners to understand processes and requirements.
Contributed across the full development lifecycle, including database monitoring and administration.
Developed and enhanced T-SQL and SSIS processes for data warehouse operations.
Designed and implemented conceptual, physical, and dimensional data models and delivered new data marts.
Created, maintained, and optimized T-SQL reports, queries, and processes to improve performance and reliability.
Tech stack: MS SQL 2012, SSIS, TFS, VSTS, Jira, Confluence.

Nov 2017 - Dec 2017

2 months

London, United Kingdom

MSSQL Backend Specialist / Consultant, Data Architect

Chanel

Optimized existing data warehouse processes and reporting solutions while leading initiatives to design and implement a modern data architecture.
Built a proof of concept for a new data warehouse, recommending best practices and optimizations for ETL.
Collaborated with stakeholders to capture requirements and design a Kimball-based architecture including a Power BI data model.
Developed a new ELT framework using SSIS and T-SQL with logging, auditing, error handling, self-healing, incremental loading, row-level security, and CDC.
Designed and delivered Power BI data models and reports for business insights and decision-making.
Tech stack: MSSQL 2012, SSIS 2012, SharePoint 365, C#, Power BI, DAX, Power Query, Data Vault, VSTS.

Jul 2017 - Nov 2017

5 months

London, United Kingdom

MSSQL Specialist, Lead Report Developer

ASOS

Implemented reporting solutions for CRM, managing the full development lifecycle with business stakeholders.
Designed, built, and deployed an SSRS and Power BI suite with row-level security for AX 365 to support accounting and finance.
Gathered requirements and performed gap analysis with senior stakeholders to align with business needs.
Developed and optimized conceptual, physical, and dimensional data models using the Kimball methodology delivered through AOS objects.
Created custom AOS Entities, Data Entities, T-SQL, SSRS, and X++ objects for reporting and integration.
Tech stack: MSSQL 2016, SSIS 2016, SSRS 2016, AX Dynamics 365, TFS, Azure, VSTS, Power BI, DAX, Power Query.

Mar 2017 - Jun 2017

4 months

London, United Kingdom

MSSQL Backend Specialist / Consultant

FieldFisher

Served as senior/lead developer responsible for the full development lifecycle, working with senior management to deliver reporting solutions on the AX 365 data platform.
Gathered requirements and collaborated with stakeholders to design and deliver Power BI and SSRS reports and dashboards.
Planned and modelled data structures in AOS and Power BI for analytics and reporting.
Developed T-SQL objects for Kimball-based data warehouse layers in AX Dynamics 365, creating data entities and AOS objects with X++.
Designed and implemented SSRS and Power BI reports with row-level security for role-based access.
Contributed to DevOps processes including Azure-based code deployment and version control.
Tech stack: MSSQL 2016, SSIS 2016, SSRS 2016, AX Dynamics 365, CI, Azure, Power BI, VSTS, DAX, Power Query.

Jan 2017 - Feb 2017

2 months

London, United Kingdom

MSSQL / ETL Specialist

RSSB

Developed an ETL solution to unify multiple data sources into a single customer view, managing gap analysis, building business knowledge, testing, and deployment.
Designed and built ETL and T-SQL processes to prepare unified datasets for CRM AX NAV.
Collaborated with business users to validate requirements and ensure data quality specifications.
Tech stack: MSSQL 2016, SSIS 2016, SharePoint 365, CozyRoc, Pragmatic Works.

Aug 2016 - Nov 2016

4 months

Gibraltar

MSSQL Backend Developer / Consultant

Gala Coral

Acted as data architect and developer on a database migration project, responsible for end-to-end solution design and implementation.
Designed dimensional data models and developed ETL processes to support migration and integration.
Integrated a Kimball-based data warehouse with Salesforce CRM for advanced reporting and analytics.
Managed the full development lifecycle including UAT testing, error tracking, process logging, and data lineage.
Tech stack: MS SQL 2016, TFS, Azure PaaS, Oracle, Data Warehouse.

Jan 2016 - Apr 2016

4 months

London, United Kingdom

MSSQL Backend Developer / Consultant

Ciber

Built an automated ETL solution for data feeds into AX Dynamics 2012 CRM on Azure, ensuring reliability, scalability, and workflow integration.
Developed, tested, and integrated an SSIS solution with AX Dynamics API.
Implemented data quality checks, error handling, and process logging for transparency and resilience.
Created customized SSRS reports for internal and external users in CRM.
Provided ad-hoc and BAU support with T-SQL, SSIS, and SSRS development and maintenance.
Tech stack: MS SQL 2012, SSIS 2012, SSRS 2012, C#, Azure, KingswaySoft.

Oct 2015 - Dec 2015

3 months

London, United Kingdom

MSSQL Backend Developer / Consultant

Generali

Enhanced data feed processes across systems and the data warehouse, providing development and advisory support.
Advised on future data architecture and best practices for Microsoft technologies.
Developed SSRS reports and delivered ad-hoc business support to meet client needs.
Tech stack: MS SQL 2008 R2, SSIS, SSRS, T-SQL.

Jul 2015 - Oct 2015

4 months

London, United Kingdom

MI Developer / Consultant

PIAS

Delivered a new ETL data feed to the data warehouse integrating sales and royalty fee information using SSIS, C#, and T-SQL.
Planned and modelled solution architecture as data architect ensuring scalability and performance.
Developed a metadata-driven ETL process with robust error handling, CDC, and full data lineage.
Designed and implemented automated, self-healing ETL pipelines ingesting high-volume data from external APIs (Spotify, Apple, Google).
Tech stack: MS SQL 2012, SSIS, Tableau, C#, REST APIs, PowerShell, XML, JSON.

May 2015 - Jul 2015

3 months

London, United Kingdom

MSSQL Backend Developer / Consultant

NBC Universal

Delivered BI enhancements for internal clients while supporting BAU processes for reliable data operations and continuous improvement.
Developed and maintained ETL solutions using T-SQL, SSIS, and C#.
Implemented and tested an ETL migration across multiple source environments within a complex broadcast data structure.
Tech stack: MS SQL 2008 R2, SSIS, SSRS, T-SQL, PL-SQL, TFS, C#, Oracle 11g.

Dec 2014 - Apr 2015

5 months

London, United Kingdom

Data Architect / MSSQL Backend Developer

WorldRemit

Delivered a new OLTP data architecture for APIs and front-end applications, modernizing data processes and removing legacy limitations.
Optimized data processes using Azure PaaS and SQL Server 2012, collaborating with business owners on requirements and database design.
Developed a PoC resolving architectural bottlenecks using sharding and in-memory tables for load balancing.
Enhanced security with Always Encrypted, access control, and data hashing/masking.
Designed an incremental data feed to a Kimball data warehouse for near real-time reporting with minimal latency.
Tech stack: MS SQL 2014, SSIS, SSRS, Git, Erwin, VBA, C#, Excel DAX, PowerShell, Red Gate, Azure PaaS.

Jan 2013 - Nov 2014

1 year 11 months

London, United Kingdom

Senior MI Developer / MSSQL Backend Developer

Net-a-Porter

Delivered solutions and PoCs for a Kimball-based data warehouse across multiple projects, collaborating with accounting, operations, marketing, and procurement departments.
Designed, developed, tested, and deployed SSIS, T-SQL, and SSRS components for enterprise reporting and analytics.
Acted as developer DBA, optimizing T-SQL and SSIS for high-volume structured and unstructured data, including Amazon Hadoop integration.
Delivered key marketing reports for customer segmentation and longitudinal analysis, creating a single customer view.
Enhanced the data warehouse with CDC, data quality auditing, process orchestration, and advanced error handling.
Implemented DevOps practices with CI using TeamCity and Redgate across BI projects.
Tech stack: MS SQL 2008 R2, SSIS, SSRS, SSAS, Team Foundation, Red Gate, MySQL, PostgreSQL, .NET, VBA, BIML, CozyRoc, TeamCity.

Mar 2012 - Jan 2013

11 months

Grays, United Kingdom

MSSQL Backend Developer

EC Group

Developed a bespoke accounting system using T-SQL with AX Dynamics 2008 as the primary data source.
Tech stack: MS SQL 2008 R2, SSIS, SSRS, AX Dynamics 2009, XML, SharePoint, BizTalk.

May 2011 - Jan 2012

9 months

Bristol, United Kingdom

MSSQL Backend Developer

Consumer Intelligence

Developed an automated SQL solution to generate phantom profiles and ensure data readiness, improving efficiency and reliability.
Tech stack: MySQL 5.6, C#, ETL scripts, unit testing.

Feb 2011 - May 2011

4 months

Basildon, United Kingdom

MSSQL Consultant / Developer

Drakefield Insurance Services Limited

Supported an insurance client with database migration, reporting, and BAU operations to ensure smooth data management and business continuity.
Tech stack: MS SQL 2005, SSIS, SSRS.

Jun 2006 - Dec 2009

3 years 7 months

Manchester, United Kingdom

MI Developer / Geo SQL Analyst

Manchester Geomatics Ltd

Responsible for spatial analysis, data quality, geo-accuracy, and data transformation to support online services.
Tech stack: MySQL, MS SQL 2005, Excel, MapInfo, ASP.NET, .NET, geocoding ETL, segmentation, longitudinal analysis, unit testing.

Industry Experience

See where this freelancer has spent most of their professional time.

Experienced in Information Technology, Retail, Fashion, Banking and Finance, Energy, and Insurance.

Information Technology

Retail

Fashion

Banking and Finance

Energy

Insurance

Business Area Experience

See which departments and functions this freelancer has contributed to most.

Experienced in Business Intelligence, Information Technology, Quality Assurance, Accounting, and Finance.

Business Intelligence

Information Technology

Quality Assurance

Accounting

Finance

Summary

Senior Data Engineer / MSSQL BI / Backend specialist and consultant with 15+ years of experience in development, data architecture, DBA development, and DevOps. Skilled in leading and mentoring teams, with proven expertise in data modelling, data processing, and end-to-end data solutions delivery. Experienced in collaborating directly with clients to design and implement solutions that meet business needs and expectations.

Specialised in designing and executing full data solutions, including ETL, DWH/Data Vault, data integration, transformation, modelling, reporting, and visualisation. Extensive experience as a BI developer across diverse environments and data design patterns. Adept at delivering bespoke, automated, and robust BI solutions with a strong focus on quality assurance, performance optimisation, and scalability.

Skills

Backend Development

Design Complex Processes For A Billion-row Solution And Complex Relations.
Produce Kpis And Reports (Ssrs, Power Bi) As Requested By The Business According To Sla.
Power Bi Build Models And Security.
Unit Test, Test Driven Development.
Worked With Spatial Data.
Implement Data Encryption And Data Hashing, Db Migration, Db/table Partitioning, Error Tracking And Solving.
Level Security (Rls), Column Level Security (Cls).
Design And Implement The Etl/elt Process.

Data Architecture

Data Architecture And Data Modelling From Conceptual Through Logical To Physical.
Olap Data Modelling: Data Warehouse - Kimball And Inmon (Facts And Dimensions, Slowly Changing Dimensions, Star Schema, Snowflake Schema), Data Vault 1.0/2.0 (Hubs, Satellites And Links), Change Data Capture (Cdc).
Oltp Data Models, Entity-relationship, Db Normalisation And Denormalisation (3f, 5f).
Data Quality, Consistency And Lineage.

Development Dba

Optimising T-sql.
Creation And Maintenance Of Indexes, Constraints, Jobs/schedules, Replication, And User Permission Management.
Db Backups.

Devops

Set Up Ci/cd (Continuous Integration And Deployment).
Source Control.
Code Review, Deployments, Mergers.

Tech Stack

Microsoft Sql Server Version: 2005, 2008 R2, 2012, 2014, 2016, 2017, 2019, 2022.
Microsoft Bi Stack: Ssis, Ssrs, Ssas, T-sql, Sssis Extensions Cozyroc, Kingwaysoft.
Apex And Red Gate Sql Tools, Ssms, Workbench, Dbeaver, Pgadmin.
Mysql 4.x & 5.x., Oracle 11g And Postgresql 8.2, Exasol, Amazon Redshift.
Mapinfo And Arcgis, Surfer.
Ms Excel, Power Bi, Dax, Tabular Model, Power Queries, Dax Studio, Tabular Editor.
Jira, Confluence, Documentation.
T-sql, Plsql, Vba, Html, Xml, Json, C# .Net, R, Python And Powershell.
Teamcity, Ms Build, Vsts, Microsoft Team Foundation Framework And Github.
Ax Dynamics 2009, 2012, Dynamics 365.
Dbschema, Schema Creator In Ssms And Workbench, Draw.io.
Erp/crm: Ax Dynamics 2009, 2012, 365, Salesforce.

Languages

Polish

Native

English

Advanced

German

Intermediate

Education

Oct 2011 - Jun 2012

UniGIS U.K.

Postgraduate certificate degree, Geographic Information Systems · Geographic Information Systems · United Kingdom

Oct 2004 - Jun 2005

The University of Manchester

School of Geography · Manchester, United Kingdom

Oct 2002 - Jun 2006

Nicolaus Copernicus University

School of Geography · Poland

Statistics

Experience

Total positions 25

Experience in Information Technology 6 y

Avg length 6 m

Longest experience 3 y 6 m

Global Experience

Countries worked in 5 (United Kingdom, Germany, Poland, Switzerland, Gibraltar)

Primary country United Kingdom

Expertise

Recent roles MSSQL Backend / Data Engineer Specialist, Data Modelling Expert, MSSQL Backend Specialist / Consultant

Main industries Information Technology, Retail, Fashion

Main business areas Business Intelligence, Information Technology, Quality Assurance

Qualifications

Profile

Created

April 2026

Need a freelancer? Find your match in seconds.

Try FRATCH GPT

Frequently asked questions

Do you have questions? Here you can find further information.

Where is Jakub based?

Jakub is based in Toruń, Poland.

What languages does Jakub speak?

Jakub speaks the following languages: Polish (Native), English (Advanced), German (Intermediate).

How many years of experience does Jakub have?

Jakub has at least 14 years of experience. During this time, Jakub has worked in at least 16 different roles and for 25 different companies. The average length of individual experience is 1 year and 7 months. Note that Jakub may not have shared all experience and actually has more experience.

What roles would Jakub be best suited for?

Based on recent experience, Jakub would be well-suited for roles such as: MSSQL Backend / Data Engineer Specialist, Data Modelling Expert, MSSQL Backend Specialist / Consultant.

What is Jakub's latest experience?

Jakub's most recent position is MSSQL Backend / Data Engineer Specialist at Schneider Electric.

What companies has Jakub worked for in recent years?

In recent years, Jakub has worked for Schneider Electric, New Work SE, Credit Suisse, Grundfos, and Zurich Insurance.

Which industries is Jakub most experienced in?

Jakub is most experienced in industries like Information Technology, Retail, and Fashion. Jakub also has some experience in Banking and Finance, Energy, and Insurance.

Which business areas is Jakub most experienced in?

Jakub is most experienced in business areas like Business Intelligence, Information Technology, and Quality Assurance. Jakub also has some experience in Accounting, Finance, and Project Management.

Which industries has Jakub worked in recently?

Jakub has recently worked in industries like Energy, Banking and Finance, and Insurance.

Which business areas has Jakub worked in recently?

Jakub has recently worked in business areas like Business Intelligence, Information Technology, and Project Management.

What is Jakub's education?

Jakub attended UniGIS U.K. for Geographic Information Systems.

What is the availability of Jakub?

Jakub is immediately available full-time for suitable projects.

What is the rate of Jakub?

Jakub's rate depends on the specific project requirements. Please use the Meet button on the profile to schedule a meeting and discuss the details.