This case study details the collaboration between a global eCommerce company and Pythian to enhance data management and analytics capabilities. The organization, headquartered in Canada, faced significant challenges due to a fragmented data strategy following multiple acquisitions. This fragmentation hindered their ability to gain critical insights into customer metrics and performance indicators, leading to missed revenue opportunities and inefficient marketing efforts. To address these issues, the company partnered with Pythian to develop a Gross Transaction Volume (GTV) data mart, centralizing their data across various product lines. The implementation utilized Google BigQuery, Dataform, and Jupyter Notebooks to optimize data analytics and governance. As a result of this collaboration, the eCommerce company achieved a unified view of customer data, improved strategic decision-making, and enhanced their ability to track key performance indicators. This transformation positioned the company for sustained growth and innovation in a competitive market.