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Deliverability

Spam Complaint

When a recipient marks your email as spam, negatively impacting your sender reputation.

Definition

A spam complaint occurs when an email recipient clicks the 'Mark as Spam' or 'Report Spam' button in their email client. This action is reported to the mailbox provider and often to the sender through feedback loops. Spam complaints are among the most damaging signals for sender reputation - even a small percentage of complaints can severely impact deliverability.

Why It Matters

Spam complaints directly damage your sender reputation with mailbox providers. ISPs track complaint rates closely - exceeding thresholds (typically 0.1%) triggers filtering, throttling, or blocking. High complaint rates can land you on blacklists and destroy email deliverability.

How It Works

When a recipient clicks the spam button, their mailbox provider records this. Providers with feedback loops send complaint notifications to senders. The complaint affects your reputation with that provider. Cumulative complaints across many recipients compound the reputation damage.

Best Practices

  • 1Keep complaint rates below 0.1% (Google's threshold)
  • 2Register for feedback loops with major providers
  • 3Remove complainers from your list immediately
  • 4Make unsubscribe easier than complaining
  • 5Only email opted-in subscribers

Frequently Asked Questions

Spam buttons are often more visible and convenient than unsubscribe links. Some users do not understand the difference. Some use spam buttons to bulk-clean their inbox. Make unsubscribing as easy as possible to reduce spam complaints.

The complaint is recorded by the mailbox provider, affecting your reputation with them. If you have a feedback loop, you receive notification and should remove that address. Too many complaints trigger filtering or blocking of your emails.