Hello @JanW
Following up on the answer above from @saurabh18cs and the results of a quick API test. Thank you for setting out what you tried and how you compared it with an app outside a space. That made the case easy to reproduce
Short answer: You are not missing a setting. The answer above is right: An app in an App Space cannot take a Lakebase database today. I tried both resource routes through the API, and both were rejected. If the app needs Lakebase now, build it outside a space, where a Lakebase database is a documented app resource.

Qn. "Am I missing something or is this not possible yet?"
It is not possible yet, as far as I can find. As of date (November 3, 2026) I tested both resource routes with the Databricks CLI on AWS:
- A resource on the app:
databricks apps create-update with a postgres resource returned "Apps in space ... cannot declare a resource of this type on the app. Allowed resource types: []". A SQL warehouse got the same error, so an app in a space cannot declare any resource of its own.
- A shared resource on the space: The Terraform app_space resource lists
postgres as a space resource type and says that resources on a space are granted to the space's own service principal. Adding one with databricks apps update-space returned "Space ... has no principal to grant shared resources to". The space I created through the API had no service principal. A second space with the resource in the create request failed the same way.
Options for now:
Before you rely on this:
- Testing: I tested only via the CLI and the REST API, not the App Spaces UI. If your space settings page offers Lakebase under Shared resources, that would change the answer.
- Check before you act: A space created in the UI may have a service principal where mine did not. The first command below shows whether your space has
service_principal_client_id set. If it has one, the second command attaches the database to the space. I could not run that case, so I would like to hear the result.
- Beta: Genie App Builder and App Spaces are both Beta, so the resource rules may change.
databricks apps get-space my-space -o json
databricks apps update-space my-space resources --json '{
"resources": [{
"name": "postgres",
"postgres": {
"branch": "projects/my-project/branches/production",
"database": "projects/my-project/branches/production/databases/databricks-postgres",
"permission": "CAN_CONNECT_AND_CREATE"
}
}]
}'
Happy to look at the get-space output if you run it on your space.
Hope this helps!
LK