Etsy now handles tax collection and remittance globally due to evolving jurisdictional requirements. Their tax calculation process involves determining tax during the shopping cart phase, utilizing buyer/seller location, product category, and tax rules. Etsy partners with Vertex, using their Quotation Request and DistributeTaxRequest APIs for accurate calculations and continuous updates. Order and tax details are synced with Vertex, even for cancellations and refunds, ensuring comprehensive transaction records. Vertex generates reports and audit data, which Etsy imports for analysis after the data is moved to transaction detail table from tax journal database by a cron job. Etsy maps its product categories to Vertex's rule drivers to correctly determine tax applicability. To manage increased API traffic, Etsy implemented multiple Vertex instances, separating quotation and distribution calls for scalability. They also use shadow logging to simulate stress on Vertex and monitor the checkout experience before releasing new features. This process allows them to ensure performance is not impacted while navigating increasing tax complexities and traffic volume. Future improvements will address analytics, reporting, and configuration synchronization.