@nymbalhq/email-resend

The resend email provider for Nymbal. It sends every transactional mail over Resend's SMTP relay, and takes Resend's bounce and complaint webhooks, so a permanent bounce or a spam complaint stops alert mail to that address.

npm install @nymbalhq/email-resend nodemailer

// nymbal.config.ts
commerce: {
  email: {
    provider: 'resend',
    config: {
      from: '[email protected]', // an address on a domain verified in Resend
      smtp: { pass: env('RESEND_API_KEY') },
      webhookSecret: env('RESEND_WEBHOOK_SECRET'),
    },
  },
}

• smtp.host defaults to smtp.resend.com, smtp.port to 587 (STARTTLS) and smtp.user to resend. For implicit TLS set port: 465, secure: true.
• smtp.pass is a Resend API key with sending access.
• smtp.pass and webhookSecret may be left out of the config and saved in the admin's Settings instead.
• webhookSecret is the webhook's signing secret (whsec_…, Resend: Webhooks, the endpoint). Without it the store refuses every webhook post and the email slot's health is degraded.

Webhooks

In Resend, add a webhook endpoint at <api origin>/api/webhooks/resend subscribed to:

• email.bounced
• email.complained

A Permanent bounce is recorded as a hard bounce (resend.bounced.v1) and a complaint as resend.complained.v1, one per recipient; both stop alert mail to the address. A Transient or Undetermined bounce is soft and stops nothing. Any other event posted to the same URL is answered 200 and ignored.

Only a post whose Svix signature matches the secret, with a timestamp within five minutes of the server's clock, is accepted. Resend's retry of a post keeps its svix-id, and the store records each id once.