(WarpStream co-founder)

It requires some form of object storage (S3, GCS, Azure blob storage, etc). You could use minio if you want to host the storage yourself, although I think I need to make a few changes to make that configurable in the agent.

For local development you can use an in-memory or local file storage, but not for "real" usage.

Okay - yes, it would make a lot of sense as a Kafka alternative to those of us who prefer to stay away from the public clouds.