Email suppression lists

Email suppression lists prevent repeated delivery attempts to addresses that recently failed or reported unwanted mail. Clerk uses suppression lists to protect your domain reputation and to avoid sending emails that providers are likely to reject.

If an address is on a suppression list, Clerk won't send more emails to that address until it's removed from the list. This can affect verification emails, invitation emails, and other email templates delivered by Clerk.

Why addresses are suppressed

An email address can be added to a suppression list when a provider reports that future delivery attempts are likely to fail or harm your sending reputation. Common causes include:

• Hard bounces — The recipient mailbox doesn't exist, can't receive mail, or permanently rejected the message.
• Spam reports — The recipient marked a Clerk-delivered email as spam or junk.
• Provider blocks — The receiving provider rejected the message because of policy, reputation, or filtering rules.

Suppression lists help prevent repeated attempts to invalid or unwanted recipients. Without them, every retry can increase bounce rates, spam complaint rates, or provider blocks for your domain.

How suppression appears in Email Logs

In the Clerk Dashboard, navigate to the Email Logs⁠ page to view suppression-related events such as bounce, spam_report, or dropped.

bounce and spam_report events can automatically place a recipient on a suppression list. Provider blocks can also lead to suppression. A dropped event with a suppression-related reason usually means Clerk didn't attempt delivery because the recipient was already suppressed. Since suppression lists are created automatically, you can't manually add an address to one from the Clerk Dashboard.

When to remove an address

Remove an address from a suppression list only after you understand why it was suppressed. Before you remove an address, confirm that:

• The email address is spelled correctly.
• The recipient mailbox exists and can receive mail.
• The recipient expects to receive email from your application.
• The issue that caused the bounce, block, or spam report has been resolved.

To remove an address from a suppression list:

1. In the Clerk Dashboard, navigate to the Email Logs⁠ page.
2. Select a qualifying suppression-related event for the recipient, such as a bounce, spam_report, or suppression-related dropped event.
3. If you have permission to manage instance configuration, in the event details, select Remove.

After you remove the address, trigger a new sign-up, sign-in, invitation, or verification flow to send a new email. Removing an address doesn't resend past emails or change past Email Log events.

Best practices

• Use email verification codes instead of email links when possible, especially for Microsoft Outlook and Office 365 recipients.
• Use Clerk's default email templates unless you have a clear reason to customize them.
• Keep a working mailbox behind your "from" address.
• Monitor bounce rates and spam complaint rates during launch and domain warm-up.
• Avoid repeatedly removing an address that continues to bounce or report spam.