Resend

Resend sends two types of emails:

Magic-link sign-in — single-form login, sent to existing viewers
Private stream invite — outbound from /dashboard/invites

There's only one template (packages/mail/src/templates/magic-link.ts) — it does both jobs.

Setup

Verify a sending domain

resend.com/domains → Add domain → enter your domain. Resend gives you SPF, DKIM, and DMARC records to add to your DNS. Apply them in Cloudflare DNS.

Wait ~15 minutes for verification. Refresh the Resend dashboard until status flips to "verified".

Get the API key

resend.com/api-keys → Create API key → name it HowlCast prod. Copy.

Set the secrets

# locally
echo "RESEND_API_KEY=re_yourkey" >> apps/server/.env
echo 'MAIL_FROM=HowlCast <invites@mail.your-domain.tv>' >> apps/server/.env

# prod (push via alchemy)
bun run deploy

MAIL_FROM must be at the verified domain. Common gotcha: using noreply@gmail.com — Resend rejects.

Local fallback (mailpit)

For local dev without Resend, the mail package falls through to SMTP. Spin up mailpit in Docker:

bun run dev:mail        # starts mailpit on :1025 (SMTP) + :8025 (UI)
bun run dev:mail:logs   # tail
bun run dev:mail:stop   # tear down

Set SMTP_URL=smtp://localhost:1025 in apps/server/.env. Magic-link emails appear in the mailpit UI at http://localhost:8025.

If neither RESEND_API_KEY nor SMTP_URL is set, the mail package logs the magic-link URL to console. Useful for reading the link without setting up infra. Useless in prod — log scraping is brittle.

Rotation

Generate a new API key, add it as RESEND_API_KEY, redeploy, then revoke the old one in the Resend dashboard. Plan on ~30s of mail downtime during the swap.

Troubleshooting

Magic-link email never arrives — check RESEND_API_KEY is set, MAIL_FROM is at a verified domain, recipient isn't blocked. Resend dashboard "Logs" tab shows delivery status.
Resend 403 / 422 — almost always a MAIL_FROM domain mismatch.
Console fallback fires in prod — neither secret is set. Check bun run deploy actually pushed RESEND_API_KEY.

Next: Twitch + emotes.