What is Complaints?

When an email recipient marks a message as “spam” within their mail client, the sender receives an automated notification, commonly known as a feedback loop (FBL) message. These FBL messages serve as complaints and indicate that a recipient has identified the email as unsolicited or unwanted. The total count of these complaints is an important email-centric metric that can significantly impact a sender’s reputation.

“Complaints” in email marketing refer to the instances where recipients mark emails as spam or unsolicited, indicating their dissatisfaction with the received messages.

Complaints play a crucial role in email deliverability and sender reputation. When mailbox providers observe many complaints associated with a sender’s email campaigns, they perceive it as a negative signal. A high complaint rate raises concerns about the quality and relevance of the sender’s messages, potentially leading to adverse consequences for future email deliverability.

A sender’s reputation is closely tied to the complaint rate. A high number of complaints can result in mailbox providers treating the sender as a potential source of spam, which can lead to their emails being filtered into recipients’ spam or junk folders. Ultimately, this can reduce the chances of genuine emails reaching the intended recipients’ inboxes, impacting engagement and desired outcomes.

Email senders should focus on implementing best practices to mitigate the impact of complaints and maintain a positive sender reputation. These include obtaining explicit permission from recipients before sending emails, ensuring that content aligns with recipients’ expectations, employing proper list hygiene to remove inactive or unengaged subscribers, and promptly honoring unsubscribe requests. By adhering to these practices, senders can minimize the likelihood of recipients marking their emails as spam and mitigate the negative effects on their reputation.


1. How can I monitor and track the number of complaints received for my email campaigns?
To monitor and track complaints, leveraging the feedback loop (FBL) services provided by mailbox providers or third-party email deliverability platforms is essential. These services allow you to receive automated notifications when recipients mark your emails as spam. By monitoring and analyzing these complaints, you can gain insights into potential issues and take necessary actions to improve your email marketing practices.

2. What are the consequences of a high complaint rate for email deliverability?
A high complaint rate can have significant consequences for email deliverability. Mailbox providers use complaint rates as a signal to identify potential spam senders. If your complaint rate exceeds certain thresholds, your emails may be filtered into recipients’ spam folders, decreasing visibility, open rates, and overall engagement. Maintaining a low complaint rate is crucial to preserve deliverability and ensure that your messages reach the intended audience.

3. How can I reduce the complaint rate for my email campaigns?
Reducing the complaint rate requires implementing various strategies. Start by ensuring that your email lists only include recipients who have explicitly opted in to receive your emails. Focus on providing valuable and relevant content to your subscribers, segmenting your lists to target specific interests, and personalizing your messages. Promptly address any complaints or feedback received and make it easy for recipients to unsubscribe from your communications.

4. Can complaints be used as feedback to improve email marketing practices?
Yes, complaints can serve as valuable feedback to improve email marketing practices. Analyzing the reasons behind complaints can provide insights into potential issues such as irrelevant content, excessive frequency, or poor list quality. Addressing these concerns and making necessary adjustments can enhance the overall subscriber experience and reduce the likelihood of future complaints.

5. Are there any industry benchmarks for complaint rates?
While there are no universal industry benchmarks for complaint rates, it is advisable to compare your complaint rates against your own historical data and industry averages, if available. This allows you to identify trends, gauge the effectiveness of your email campaigns, and make data-driven improvements to your email marketing strategies.

6. How frequently should I review and address complaints?
Regularly reviewing and addressing complaints is crucial for maintaining a healthy sender reputation. Monitoring complaint metrics on an ongoing basis, such as weekly or monthly, is recommended to identify any sudden changes or trends. Promptly investigate and address any recurring issues to minimize the impact on your sender’s reputation and email deliverability.

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