Yes, it can be integrated freely with any backend relay (nostream, nostr-rs-relay, and other relays). We just need to setup relay url config in env variable. 

This repo only integrate several modules which can be replaced and customized individually. 

 love2know thanks will try it out later - seems it sits like proxy layer once config correctly.
 

 Yes, it sits like a proxy relay in front of its backend relay. Let me know your experieces self-host it 👀