This article examines the experience of a large research library when it migrated its collections materials purchasing onto its university’s outsourced e-procurement platform. Previously, the library used a homegrown legacy workflow to export invoice data directly from the integrated library system (ILS) to Accounts Payable to initiate payments to suppliers. Adopting the procurement platform has produced benefits for both the university and the library by bringing the library into alignment with standard campus workflows and improving visibility into collections materials spending. The move has also posed challenges for the library, which has had to adapt to new tasks in another system running parallel to its ongoing acquisitions work in the ILS. The article describes the legacy workflow, the campus platform, the migration project, and the library’s continuing efforts to optimize its workflows to meet the campus platform’s requirements while completing work in the ILS as efficiently as possible.