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 only available for organizations. Individual users and teams cannot configure their own SMTP settings.

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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

You must be an organization admin to configure custom SMTP. Before getting started, 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 (TLS)
Username	The account used to authenticate	[e-mail]
Password	The password or app-specific password	—
Secure connection	Whether the server uses SSL/TLS	Yes for port 465, typically
From email	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

Organization admins can configure custom SMTP directly from the organization settings. To get started, ask your Cal.com account representative to enable the custom SMTP feature flag for your organization.

Once the feature is enabled, follow these steps:

1. Open organization settings

   Go to your organization settings in the Cal.com dashboard.

2. Enter your SMTP details

   Fill in the required fields:

   • From email — the address that appears in the “From” field
   • From name — the display name next to the email address
   • SMTP host — your mail server address
   • SMTP port — the port your server uses (for example, 465 for SSL or 587 for TLS)
   • Username — the account used to authenticate
   • Password — the password or app-specific password
   • Secure connection — enable this if your server uses SSL/TLS (recommended)
3. Test the connection

   Use the test connection option to verify that Cal.com can reach your SMTP server and authenticate with the credentials you provided.

4. Send a test email

   Send a test email to confirm that messages are delivered correctly from your configured “From” address. Enter a recipient email and check your inbox to verify delivery.

5. Save your configuration

   Once the test email arrives successfully, save your configuration. All supported email types will now be sent through your SMTP server.

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Test your configuration

After saving your SMTP settings, you can verify them at any time:

• Test connection — confirms that your SMTP server is reachable and your credentials are valid
• Send test email — delivers a test message to an email address you specify, so you can confirm that emails arrive from your configured “From” address

If either test fails, double-check your SMTP host, port, username, and password with your email provider.

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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

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.

Can I update my SMTP settings after saving?

Yes. You can update any of your SMTP settings at any time from your organization settings. Changes take effect immediately for all future emails.

What happens if I remove 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.