Connect CRM-NG SMTP to Resend with an API key that has sending access and a verified domain.

This guide shows you how to send your WordPress email through Resend, a modern email API popular with developers. It suits sites that want quick setup and a tidy dashboard. Resend has a free plan with monthly and daily limits; check its site for the current figures.

The Resend mailer sends through Resend's API with an API key. Resend only delivers mail from domains you have verified.

Before you start

• A Resend account (sign up at https://resend.com/).
• A domain you control, with access to its DNS records.
• Administrator access to your WordPress site.

Step 1: Add and verify your domain

1. Sign in to Resend

   Go to https://resend.com/ and sign in.

2. Open Domains

   Open Domains in the side menu and choose Add Domain.

3. Enter the domain

   Type the domain you send from and pick a region close to your audience if Resend asks.

4. Publish the records

   Resend lists a DKIM TXT record, plus an MX and an SPF TXT record on a sending subdomain (usually send.yourdomain.com). Add them at your DNS provider exactly as shown.

5. Verify

   Return to Resend and press Verify DNS Records until the domain shows as verified.

See Adding DNS records for help with DNS.

Step 2: Create an API key

1. Open API Keys

   Open API Keys in the side menu (the plugin's link goes to https://resend.com/api-keys) and choose Create API Key.

2. Name it

   Use a name that identifies the site.

3. Set the permission

   Choose Sending access. You can also limit the key to your verified domain.

4. Copy the key

   Create the key and copy it now; it starts with re_ and Resend shows it once.

Step 3: Connect in CRM-NG SMTP

1. Choose the mailer

   In WordPress, open CRM-NG SMTP → Settings → General and set Mailer to Resend.

2. Paste the key

   Paste the key into API Key.

3. Set the sender

   Set From Email to an address on your verified domain, for example hello@yourdomain.com, and set From Name. Tick Force From Email so other plugins cannot use an unverified domain.

4. Save

   Press Save Settings.

Send a test email

Open CRM-NG SMTP → Tools → Email Test, enter your address in Send To, and press Send Email. Resend's Emails page shows the message and its delivery events. See Sending a test email.

Troubleshooting

• The key is wrong, deleted, or limited to another domain: 401 Unauthorized or Forbidden and Invalid API key
• The From domain is not verified: 553 Sender address rejected
• You hit the daily or monthly limit, or sent too fast: Email sending limit reached
• The recipient bounced or complained before: Email address in suppression list
• Mail arrives in spam: Emails landing in spam

Related

• Choosing a mail service
• Adding DNS records: SPF, DKIM and DMARC
• Verifying your DNS records
• Sender name, address and the Force settings
• Debug events