Deliverability
Abuse Complaint
When a recipient marks an email as spam or junk, generating a complaint to the sender's email provider.
Definition
An abuse complaint (also called a spam complaint) occurs when an email recipient clicks the "Report Spam" or "Mark as Junk" button in their email client. This action is reported back to the sender through Feedback Loops (FBLs) provided by major mailbox providers. High complaint rates severely damage sender reputation and can lead to blacklisting. Industry best practice is to maintain a complaint rate below 0.1% (1 complaint per 1,000 emails sent).
Examples
A user receives an unwanted promotional email and clicks "Report Spam" in GmailToo many complaints trigger automatic blocking by the ISP
Pro Tip
Always include a clear, one-click unsubscribe link. Users who can easily unsubscribe are less likely to file complaints.