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How to reduce spam complaint rates
How to reduce spam complaint rates

Discover effective strategies to reduce spam complaints, improve your email deliverability, and maintain a healthy sender reputation.

Gareth Burroughes avatar
Written by Gareth Burroughes
Updated over a week ago

A spam complaint is generated when a recipient reports your email as spam in one of the following ways:

  1. Selecting the "mark email as spam/junk" button.

  2. Moving the email to the spam/junk folder.

  3. Sending a complaint to a third party, such as your email-sending platform, government entity, or blocklist.

In this article, we look at ways to reduce the number of spam complaints.

The impact of a spam complaint

Recipients marking emails as spam directly and strongly indicate to the receiver that you are sending unwanted mail. This causes damage to your sender's reputation and increases the likelihood of emails landing in the spam folder or bouncing.

Causes of spam complaints

When a recipient marks an email as spam, they indicate unmet expectations. The email may not be relevant to them, or they may not have been expecting any emails from you.

Common causes of complaints

Common cause of complaints


Purchased/rented/affiliate/third-party/sister company data

Contacts are unaware of data sharing or your brand and do not expect to hear from you.

Incorrect email address collected

Accidental or intentional errors when the email address was provided.

Hidden consent

Automatic enrollment in promotional email programs, concealed consent in terms, pre-checked consent checkboxes, and confusingly labelled consent checkboxes.

Requiring subscription

Mandating sign-up to promotional emails to access services such as Wi-Fi or account creation.

Misaligned expectations

Type or frequency of emails is unclear at sign-up.

Unmet expectations

Different content or frequency than stated as sign-up.

Ignoring preferences

Not considering frequency, interest, or content type preferences settings.

No unsubscribe link

If people cannot unsubscribe, they mark emails as spam.

Not respecting unsubscribes

Continuing to send emails after opt-out.

Complex unsubscribe process

Link in email is hard to find, unsubscribe behind an account login, requires multiple steps, or re-entering email address.

Neglecting replies

Ignoring unsubscribe requests in replies.


Emailing uninterested or disengaged recipients.

Sending to old data

Contacting past subscribers who have not received emails in 3+ months and forgot they signed up.

Low brand recognition

Frequently changing friendly from name or branding, causing recipients to doubt your authenticity or not recognize your emails.

View your spam complaints

Some receivers, including Microsoft Hotmail/, Yahoo and AOL, offer feedback loops (FBLs). Dotdigital is signed up to FBLs and receives detailed reports enabling campaign-specific reporting on the number of spam complaints (labelled as an ISP complaint) and automatic suppression of the recipient in your account.

Gmail, citing privacy concerns, provides aggregate spam complaint data through Google Postmaster Tools (GPT) rather than detailed FBLs. Consequently, Dotdigital can't report Gmail complaint rates for specific campaigns or suppress recipients who mark emails as spam in your Dotdigital account. Instead, you'll need to monitor this in GPT; you can fill out this GTP access request form for your Dotdigital custom from the address domain, and a member of the team will be in touch.

High spam complaint rates

You should always aim for zero spam complaints. Rates over 0.1% may indicate current or incipient inbox placement issues. In addition to increased spam folder placement, Gmail, Yahoo and AOL may bounce emails for senders getting 0.3% or higher spam complaint rates. Postmaster teams automatically reject requests to reclassify emails as non-spam for those with complaint rates of 0.3% or higher.

Reduce spam complaints

To reduce spam complaints, you must implement deliverability best practices in your marketing strategy:

Best practice


Avoid purchasing lists

Sending to purchased lists is prohibited by Dotdigital's terms.

Only send to people who explicitly subscribe

If they're expecting to hear from you, they're less likely to complain.

Implement double/confirmed opt-in

Verify the email address is correct and belongs to the person who signed up.

Require a positive action for consent

Contacts must check a clearly labelled checkbox to sign up.

Make consent optional

If someone does not want marketing emails, they should not have to subscribe.

Set expectations

Clearly state what recipients are signing up for, including content and frequency.

Meet expectations

Ask permission first and give contacts a way to opt-out if you want to change frequency/content.

Respect preferences

Honour preferences if you have a preference centre.

Include an unsubscribe link

Make it clearly labelled and easy to find in all promotional emails.

Honour unsubscribes promptly

Stop sending emails ASAP after someone unsubscribes.

Make unsubscribing easy

Unsubscribing should not require logging in or re-confirming the email address and take only 2 clicks.

Monitor replies

Replies can contain beneficial information and unsubscribe requests.

Personalize, segment, and automate for relevancy

Utilize contact data to send tailored email content.

Sunset lapsed contacts

Stop sending emails to people who no longer engage with your brand.

Implement automations

Re-engage contacts before they lapse completely, and suppress those who continue to not engage.

Build re-engagement strategies

Combine carefully curated content with a sending plan that mitigates risk.

Consistently brand emails

Introduce a recognizable friendly from name and branding in a welcome automation triggered on sign-up.

Spam complaint help

If you'd like help in reducing your spam complaint rates, Dotdigital's expert in-house Deliverability Consultants are here for you:

  • Deliverability Scorecard: A health check report on your deliverability focused on identifying the causes of complaints and recommended actions for you to implement.

  • Deliverability Strategic Consulting: we'll partner with you to identify complaint sources, craft a reduction strategy, help monitor the results as you implement the changes, and provide further guidance. This includes training on and access to our inbox placement and sender reputation platform, which provides insights into whether your emails are landing in the inboxes of over 90 global receivers.

Contact our support team or your Customer Success Manager for information about Deliverability Scorecards and Deliverability Strategic Consulting.

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