Multiple data sources

How to resolve the "Databases with multiple data sources are not supported" error in Whalesync

Databases with multiple data sources are not supported in this API version.

On September 3, 2025, Notion updated their API to allow multiple data sources per database. A data source is a set of pages in a database — so a single database can now contain several independent collections of pages.

Whalesync fully supports multiple data sources on all newly created syncs. However, this change is not backward-compatible with syncs that were created before the update.

If you're seeing the error above, you have two options:

Option 1: Create a new sync

Create a new sync in Whalesync. New syncs use the latest Notion API version and support multiple data sources out of the box.

Option 2: Remove extra data sources in Notion

If you'd prefer to keep your existing sync, you can remove any additional data sources from the Notion database so that it only contains a single data source.

To do this, open the database's view settings and click Manage data sources:

Open view settings, then click "Manage data sources"

Then click the ••• menu next to the extra data source and choose Move to to relocate it to another database:

Use the ••• menu to move or delete extra data sources

Once a database has only one data source, the existing sync will work as before.