Oddbean new post about | logout
 Use reCAPTCHA v3.
Also, post honeypots that only bots can see, and when they engave with them (which regular useds won't do as they won't see them) ban them. 
 IMHO, using recaptcha would be like using “Sign in with Google”. 
 Recaptcha would have to become a NIP since all of this happens over websockets and not basic HTTP. And then nostr clients would need to add support for recaptcha.