The Swedish National Data Service (SND) maintains metadata about its holdings in the Data Documentation Initiative's DDI-Lifecycle format. The total amount studies in the holdings amounts to over one thousand, both quantitative and qualitative. SND stores and indexes this metadata using eXist-db, an open source XML database. Colectica is another DDI 3-based tool, but by default it uses a different repository structure for storing metadata. In order to allow Colectica tools to interact with SND metadata, we implemented a set of Web Services on top of eXist-db that allow Colectica to store and load information using eXist-db. We will demonstrate functionality provided by the eXist-db system, discuss the steps we took to integrate with Colectica, and demonstrate the resulting functionality with the two systems working together. We will also present recommendations on how to interact between DDI repositories in general and DDI tools. Implementations on our approach could be done from other DDI repositories.