Forcing sign-in to be "log in using email" wiped out +90% of spam for the ~300 forums I run. I use auth0 now in a passwordless setup, and it requires either Go

Forcing sign-in to be "log in using email" wiped out +90% of spam for the ~300 forums I run. I use auth0 now in a passwordless setup, and it requires either Google Auth, Windows (Hotmail) Auth or a one-time-token being emailed to the person (with a 15 minute expiry). It has required that I pay for Sendgrid to ensure the email delivery... but it's worth it. I deal with virtually no spam nowadays and the biggest cure was this one thing.