This document summarizes a new online tool created for ISMN agencies in the Netherlands. The tool aims to automate common ISMN actions, reduce manual work, build a complete catalog of titles, and be accessible and flexible. It allows publishers to request accounts, pay for ISMN prefixes, add title information in batches using Excel, and pay for assigned ISMN numbers. The agency can oversee publishers and prefixes, activate new accounts, and the public can search the catalog. The conclusion is that the tool automates nearly all actions, creates a full searchable title catalog, and provides a flexible, open source, web-based system for ISMN management.