Resend Email Setup

How to configure Resend for transactional email and newsletter subscriptions.

Last updated: April 12, 2026

Create a Resend account

Sign up at resend.com
Go to API Keys → Create API Key
Name it (e.g., BloggFast Production) and give it Full access
Copy the key — you can only see it once

Verify your domain

For production, verify your sending domain under Domains in the Resend dashboard. Add the DNS records Resend provides to your domain registrar. Without domain verification, emails may land in spam or be limited to Resend's sandbox.

Note

During development, you can use onboarding@resend.dev as the from address to send test emails to your own account without domain verification. Resend's free tier allows 3,000 emails/month.

Configure environment variables

.env.local

RESEND_API_KEY=re_...
RESEND_FROM_EMAIL=hello@yourdomain.com
RESEND_WEBHOOK_SECRET=whsec_...    # Optional: for webhook event handling
RESEND_AUDIENCE_ID=               # Optional: for Resend Contacts sync

Email flows in BloggFast

BloggFast uses Resend for these email flows (defined in src/lib/resend.ts):

Function	When it fires	Template
`sendSubscriptionConfirmationEmail`	When a user submits the newsletter subscription form	HTML with a tokenized confirmation link
`sendWelcomeEmail`	After subscription is confirmed via the confirmation link	HTML welcome message
`upsertSubscriberContactInResend`	After confirmation — syncs the subscriber to Resend Audiences (if `RESEND_AUDIENCE_ID` is set)	N/A — API call only
`unsubscribeContactInResend`	When a subscriber opts out	N/A — removes from Resend Audience

Webhook setup (optional)

BloggFast includes a Resend webhook handler at /api/webhooks/resend (via the Svix verification library) that handles bounce and complaint events. To enable:

In your Resend dashboard, go to Webhooks → Add Endpoint
Set the URL to https://yourdomain.com/api/webhooks/resend
Select events: email.bounced, email.complained
Copy the signing secret → set as RESEND_WEBHOOK_SECRET

Webhook events automatically update subscriber statuses in the database (BOUNCED, COMPLAINED) and log to the SubscriberEvent table.

Audience sync (optional)

If you want to sync subscribers to a Resend Audience (for broadcast emails), create an audience in the Resend dashboard and add the ID to your environment:

.env.local

RESEND_AUDIENCE_ID=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx

If this variable is not set, the app skips the contact sync step without errors — email sending still works normally for transactional flows.