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Email (sign-in links)

spellcache has no passwords: users sign in with a one-time link or code sent by email. Emails go through Resend.

  1. Create a Resend account and verify your sending domain (DNS records shown by Resend).

  2. Create an API key and set it in .env:

    Terminal window
    RESEND_API_KEY=re_…
    RESEND_FROM_EMAIL="spellcache <signin@your-domain.example>"

  3. Restart web: docker compose -f docker-compose.example.yml up -d web.

RESEND_FROM_EMAIL must be an address on a domain verified in Resend. Without it, Resend’s test sender is used, which only delivers to your own Resend account address.

In production the web container refuses to send sign-in emails without a Resend key: a missing key would otherwise print valid sign-in links in the logs.

SMTP

Plain SMTP is not supported today. Auth.js (the authentication library) can send through SMTP with its Nodemailer provider, so adding it is possible but requires a code change; contributions are welcome.