Table of Contents
What Is Resend?
Resend is an email delivery platform built for developers that makes it easy to send transactional emails using API or SMTP. It offers domain verification, email logs, analytics, and a simple setup flow, making it a solid option for WordPress sites that need reliable email delivery through the Master SMTP plugin.
Setting Up a Resend Account
To get started, visit the Resend pricing page:
In this example, we will use the Free plan to set up Resend.
Click Get started under the Free plan to create your account and continue.
Next, complete the account creation steps. You can create your account manually by entering your details, or use Sign in with Google for a faster one-step signup process.
After your account is created, log in to continue with the Resend setup.
Authorizing Your Domain
Before you can send emails with Resend, you need to add and verify your sending domain. This confirms that you own the domain you want to send from and helps improve email deliverability.
Adding Your Sending Domain
To add a sending domain, log in to your Resend account and go to Domains from the left sidebar, or visit https://resend.com/domains.
Then click Add domain to continue.
Enter your domain name, then choose the region you want to use.
Domain: Using a subdomain is recommended, such as mail.yourdomain.com or mailing.yourdomain.com. This can still be used for sending emails for addresses on your main domain, depending on your setup.
Region: Select the region closest to you or your main audience for the best performance.
When ready, click Add domain.
DNS Records
For Cloudflare and some other DNS providers, you can use Auto configure to add the required DNS records automatically.
If you prefer to add the records yourself, click Manual setup and copy the DNS records into your domain DNS settings manually.
If you used Auto configure, Resend will add the DNS records for you automatically. After the setup is completed, you should see your domain marked as Verified.
Note: Domain verification may take a few minutes after the DNS records are added.
Resend API Key
To create your Resend API key, click API Keys from the left sidebar, or visit https://resend.com/api-keys.
Then click Create API Key.
Enter the API key details, then click Add.
Name: Enter a clear name, such as Master SMTP.
Permission: Select Full access.
Domain: If you verified multiple domains, you can limit the API key to a specific domain, or leave it set to All Domains.
Then click Add
After the API key is created, copy and save it in a secure place. Resend only shows the full API key once, and you will need it in the next step when setting up Resend in the Master SMTP plugin.
Resend Setup in Master SMTP Plugin
In your WordPress dashboard, go to Master SMTP > Connections, then click Create New Connection.
Configure Connection
In the Configure Connection section, fill out the Connection Details fields:
Connection Details: Enter a name for this connection. This is only for you, recipients will not see it.
Default From Email: The email address used when an outgoing email does not define a From Email.
Force From Email: If enabled, this From Email will be used for all emails, even if the email has a different From Email.
Default From Name: The name used when an outgoing email does not define a From Name.
Force From Name: If enabled, this From Name will be used for all emails, even if the email has a different From Name.
Default Reply-To Email: The Reply-To address used when an outgoing email does not define a Reply-To Email.
Force Reply-To Email: If enabled, this Reply-To Email will be used for all emails, even if the email has a different Reply-To Email.
In the Choose a Mailer section, select Resend from the grid mailer list.
Resend Settings
In the Resend Settings section, paste your Resend API Key into the matching field.
If you want to use Resend as your main mailer, enable Make this the default connection, then click Save Connection.
The connection will be added to the Connections list, and you should see Connection saved. at the top of the window.
Note: The free version allows you to add only one connection. If you need multiple connections, Conditional Routing, and many other features, you should purchase the Master SMTP Pro.
Test Resend Connection
After saving your Resend connection, it is recommended to send a test email to make sure everything is working correctly. This helps confirm that your API Key, and connection settings have been entered properly and that your site can send emails successfully through Resend SMTP.
For step-by-step instructions, see the test connection guide here: