Awesome
Nostr Relay Framework -- use it to implement your own custom relay.
There is an example/reference implementation at basic. Binaries for that are also available under Releases.
<a href="https://godoc.org/github.com/fiatjaf/relayer"><img src="https://img.shields.io/badge/api-reference-blue.svg?style=flat-square" alt="GoDoc"></a>