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Beginner10 min read

Reducing Spam Complaints: A Comprehensive Strategy

Learn why users mark emails as spam and implement strategies to reduce spam complaints and protect your reputation.

Spam complaints (when recipients click "Mark as Spam") are one of the most damaging metrics for sender reputation. Even a 0.1% complaint rate can trigger deliverability issues. Here's how to keep complaints low.

Critical Threshold

ISPs typically take action when spam complaint rates exceed 0.1%. Above 0.3%, expect significant deliverability problems or blocklisting.

Why People Mark Emails as Spam

Didn't Remember Subscribing

Long delay between signup and first email, or unclear opt-in process

Too Many Emails

Sending too frequently without giving subscribers control over frequency

Irrelevant Content

Emails don't match what they signed up for or their interests

Can't Find Unsubscribe

Unsubscribe link is hidden, broken, or requires too many steps

Deceptive Subject Lines

Subject doesn't match content, or uses misleading tactics

Prevention Strategies

1. Set Clear Expectations

Tell subscribers exactly what they're signing up for:

  • What content they'll receive
  • How often you'll send emails
  • What value they'll get

2. Make Unsubscribing Easy

Best Practices

  • • Place unsubscribe link in footer of every email
  • • Make it one-click (no login required)
  • • Process immediately (within seconds)
  • • Don't ask "Are you sure?" multiple times
  • • Offer preferences (frequency, topics) as alternative

3. Send Welcome Email Immediately

Send a welcome email within minutes of signup while they still remember subscribing. This sets a positive first impression and reduces future spam complaints.

4. Maintain Consistent Sending

Don't go silent for months then suddenly email. Subscribers forget about you and mark emails as spam. Send regularly (weekly, bi-weekly, or monthly) to stay top-of-mind.

Content Best Practices

Accurate Subject Lines

Subject should accurately reflect email content. Avoid clickbait or misleading hooks.

Recognizable Sender Name

Use your company name, not a person's name or generic address like "noreply@".

Include Physical Address

CAN-SPAM requires a physical mailing address in every email. This also builds trust.

Avoid Spam Trigger Words

Minimize use of "FREE", "ACT NOW", "GUARANTEED", excessive punctuation!!!, and ALL CAPS.

Segmentation and Personalization

Send relevant content by segmenting your list:

  • By behavior: Purchase history, browsing activity, engagement level
  • By demographics: Location, industry, company size
  • By preferences: Interests, frequency, content type

Monitoring and Response

What to Track

Spam Complaint RateKeep below 0.1%
Unsubscribe Rate0.2-0.5% is normal
List Growth RateNew subs minus unsubs
Engagement TrendsOpens and clicks over time

Start with a Clean List

Invalid email addresses lead to hard bounces, which damages sender reputation and increases the likelihood of spam complaints. Validate before sending.