@feld This is the Nostr equivalent of Pleroma: https://github.com/hoytech/strfry
Truly incredible, simplicity and hyper efficiency, and has the equivalent of MRF… except you can write them in any programming language without recompiling the main program.
Check out my Hellthread Policy in TypeScript: https://gitlab.com/soapbox-pub/strfry-policies/-/blob/develop/hellthread-policy.ts
It uses stdin and stdout to filter JSON events.