What is a Spam Complaint?

A spam complaint is recorded when one of your recipients clicks the "report spam", "junk", or equivalent button in their mail client. The mail provider then notifies Amazon SES through a feedback loop, and SES forwards that notification to Mailblast.

Complaints matter more than bounces. AWS's pause threshold for complaints is 0.5% versus 10% for bounces - a complaint pulls your sending reputation down roughly 20 times harder than a bounce does. The recommended ceiling is just 0.1%, meaning 1 complaint per 1,000 emails already puts you above what AWS wants to see.

How complaints happen

Most complaints are not malicious. The common reasons:

  • The recipient does not remember signing up
  • They cannot find the unsubscribe link and the spam button is easier
  • They signed up months ago and your email no longer feels relevant
  • The from name does not match the brand they recognise (e.g. you send as "Newsletter" but they signed up at "Acme Co")

In other words, a complaint is usually a UX failure, not a malicious action.

What Mailblast does with a complaint

The moment SES tells us about a complaint, Mailblast:

  1. Suppresses that email address across all of your lists immediately
  2. Records the complaint against the campaign that triggered it
  3. Surfaces the complaint count on the campaign's report page

There is no manual step. The next campaign you send will skip that recipient automatically.

Reducing your complaint rate

If your complaint rate is creeping up, the levers in rough order of effectiveness:

  1. Make the unsubscribe link obvious. Put it in the footer with normal-sized text, not 8-pixel grey-on-grey. Subscribers who can find it use it; subscribers who cannot, hit the spam button.
  2. Use a recognisable from name and address. "Acme Newsletter hello@acme.com" beats "Newsletter noreply@mg-acme-prod.com" every time.
  3. Remind people why they are getting the email. A single line in the footer ("You are getting this because you signed up at acme.com") cuts complaints noticeably.
  4. Stop sending to people who never engage. A subscriber who has not opened anything in 12 months is more likely to mark you as spam than read you.
  5. Match the cadence you promised at signup. If they signed up for a weekly newsletter, do not start sending daily.

What it looks like on a campaign report

Complaints show up alongside bounces and unsubscribes on each campaign's report page. AWS's recommended ceiling is 0.1%, so aim well under that across your rolling average.

If a single campaign's complaint rate is much higher than your usual baseline, treat it as a signal: something in that send - the subject line, the segment, the content - did not match what subscribers expected.

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