Custom SMTP for organizations

Send booking emails from your own domain using a custom SMTP server.

Organizations on Cal.com can configure a custom SMTP server so that booking-related emails (confirmations, reminders, cancellations, and more) are sent from your own domain instead of Cal.com’s default email address.

This helps keep your communications on-brand and can improve deliverability for your team’s emails.

Custom SMTP is an enterprise feature available for organizations only. Individual users and teams cannot configure their own SMTP settings. Contact your Cal.com account representative to enable it.

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How it works

When you set up a custom SMTP configuration, Cal.com routes supported email types through your SMTP server. If your server is temporarily unreachable, Cal.com automatically falls back to its default email service so that no emails are lost.

Each organization can have one SMTP configuration at a time.

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Supported email types

Custom SMTP applies to booking-related emails, including:

• Booking confirmations — sent to both the attendee and the organizer
• Cancellations and reschedules — notifications when bookings change
• Booking requests — emails for events that require approval
• Payment emails — no-show fee notifications
• Recording and transcript links — download links after meetings
• Workflow emails — messages triggered by your custom workflows
• Routing form responses — emails from routing form submissions

Account-level emails such as password resets or login verifications are not sent through your custom SMTP server.

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What you need

Before configuring custom SMTP, have the following details from your email provider:

Setting	Description	Example
SMTP host	Your mail server address	smtp.yourcompany.com
SMTP port	The port your server uses	465 (SSL) or 587 (STARTTLS)
Username	The account used to authenticate	[e-mail]
Password	The password or app-specific password	—
Encryption	SSL/TLS (port 465) or STARTTLS (port 587)	SSL/TLS
Sending email address	The address that appears in the “From” field	[e-mail]
From name	The display name next to the email address	Your Company

Make sure your SMTP server allows sending from the “From” email address you configure. If there is a mismatch, emails may fail or be rejected by recipient mail servers.

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Set up custom SMTP

Once the feature is enabled for your organization, org admins can configure SMTP directly from the settings page.

1. Open custom email settings

   Go to Settings → Organization → Custom email.

2. Connect your SMTP server

   Click the Connect button to open the configuration form.

3. Enter your SMTP details

   Fill in the following fields:

   • Name — the display name for outgoing emails (e.g., “Your Company”)
   • Sending email address — the “From” email address
   • SMTP server name — your mail server address (e.g., smtp.yourcompany.com)
   • Encryption — choose SSL/TLS (port 465) or STARTTLS (port 587). The port is set automatically based on your selection.
   • Username — your SMTP authentication username
   • Password — your SMTP authentication password
4. Test the connection

   Click Test Connection to verify that Cal.com can reach your SMTP server with the credentials you provided. You must pass this test before saving.

5. Save the configuration

   Once the connection test succeeds, click Save to apply your SMTP settings. All supported emails from your organization will now be sent through your server.

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Test your configuration

After saving, you can send a test email to confirm everything is working end to end.

1. Open your SMTP configuration in Settings → Organization → Custom email.
2. Expand the configuration card and click Send a test.
3. Check your inbox for the test email.

If the test email does not arrive, verify your SMTP host, port, username, and password with your email provider.

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Edit or delete your configuration

To update your SMTP settings, open the configuration card and click Edit. You can change any field — if you modify connection-related settings (host, port, encryption, username, or password), you will need to pass a new connection test before saving.

To remove custom SMTP entirely, click Delete on the configuration card. All emails will revert to Cal.com’s default email address.

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Automatic fallback

If your SMTP server becomes temporarily unavailable, Cal.com automatically retries the email using its default email service. This ensures that booking emails are always delivered, even if there is an issue with your mail server.

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Frequently asked questions

Who can configure custom SMTP?

Only organization admins and owners can access the custom email settings page. The feature must also be enabled for your organization — contact your Cal.com account representative if you don’t see it in your settings.

Can I use different SMTP settings for different teams?

No. Custom SMTP is configured at the organization level and applies to all teams and members within the organization.

What happens if I delete my SMTP configuration?

All emails will be sent from Cal.com’s default email address going forward. No previously sent emails are affected.

Do I need to update DNS records?

Cal.com does not require specific DNS changes, but your email provider may require SPF, DKIM, or DMARC records to authorize the sending server. Check with your email provider for their requirements.

Which email providers work with this?

Any provider that supports standard SMTP (such as Google Workspace, Microsoft 365, Amazon SES, SendGrid, or Postmark) is compatible.

Why is the connection test required?

The connection test ensures your SMTP server is reachable and your credentials are correct before any booking emails are routed through it. This prevents email delivery failures.