How can I identify which users marked my emails as spam in Gmail?

Summary

While it's generally impossible to pinpoint specific individuals who mark emails as spam in Gmail, email senders can take several steps to understand and reduce spam complaints. Leveraging Feedback Loops (FBLs) and Google Postmaster Tools (GPT) allows senders to view aggregated data about campaigns generating high complaint volumes, though individual user data remains private. Unique unsubscribe links and Feedback-ID headers can offer limited approximations. Prioritizing best practices such as email list hygiene, obtaining explicit consent through double opt-in, sending targeted and relevant content, providing easy unsubscribe options via List-Unsubscribe headers (RFC2369), monitoring sender and IP reputation, and consistently reviewing email content are crucial in proactively mitigating spam complaints.

Key findings

  • No Direct User Identification: Directly identifying users who mark emails as spam in Gmail is generally not possible.
  • Aggregate FBL and GPT Data: Feedback Loops (FBLs) and Google Postmaster Tools (GPT) provide aggregated data on spam complaints, identifying problematic campaigns.
  • Unique Unsubscribe Links/Feedback-ID: Unique unsubscribe links and Feedback-ID headers can offer limited approximations of spam complaints.
  • Email List Hygiene: Regularly cleaning email lists by removing inactive subscribers and unengaged users improves sender reputation.
  • Double Opt-In: Implementing a double opt-in process ensures subscribers are genuinely interested, reducing spam complaints.
  • Targeted Content: Segmenting email lists and sending targeted content increases engagement and reduces spam complaints.
  • List-Unsubscribe Headers: Implementing a List-Unsubscribe header (RFC2369) provides an easy opt-out, reducing the likelihood of spam reports.
  • Sender Reputation: Monitoring sender and IP reputation through tools like Sender Score helps identify issues and trends.

Key considerations

  • Prioritize Email Best Practices: Focus on implementing email marketing best practices to prevent spam complaints, rather than attempting to identify complainers.
  • Leverage Feedback Loops: Utilize Feedback Loops and Google Postmaster Tools to identify and address issues in campaigns with high spam complaint rates.
  • Monitor Sender Reputation: Monitor sender and IP reputation to identify potential problems and take corrective action.
  • Value of User Privacy: Respect user privacy and adhere to policies that prevent the identification of complainers at an individual level.

What email marketers say
10Marketer opinions

While directly identifying users who mark emails as spam in Gmail is not possible, various strategies can help mitigate spam complaints and improve sender reputation. These include monitoring sender reputation metrics in Google Postmaster Tools and Sender Score, implementing one-click unsubscribe options with List-Unsubscribe headers, practicing rigorous email list hygiene (removing inactive subscribers), segmenting lists for targeted content, employing double opt-in processes, warming up a dedicated IP address, reviewing email content for relevance, and leveraging Feedback-ID headers for aggregated spam complaint data. The central theme is to proactively address factors that lead to spam complaints rather than focusing on identifying individual complainers.

Key opinions

  • No Direct Identification: Directly identifying users who mark emails as spam in Gmail is not possible.
  • Sender Reputation: Monitoring sender reputation through tools like Google Postmaster Tools (GPT) and Sender Score provides insights into spam complaint trends.
  • List-Unsubscribe Headers: Using one-click unsubscribe options and List-Unsubscribe headers reduces the likelihood of users marking emails as spam.
  • Email List Hygiene: Regularly cleaning email lists by removing inactive subscribers and those who haven't engaged improves sender reputation.
  • Targeted Content: Segmenting email lists and sending targeted content increases engagement and reduces spam complaints.
  • Double Opt-in: Implementing a double opt-in process ensures subscribers are genuinely interested, reducing spam complaints.
  • Dedicated IP: Warming up a dedicated IP address establishes a positive sending reputation and allows for better monitoring of spam rates.
  • Content Review: Regularly reviewing email content for relevance and avoiding misleading information reduces spam complaints.
  • Feedback-ID Header: The Feedback-ID header provides aggregated spam complaint data per identifier in Google Postmaster Tools (GPT), although it doesn't reveal individual users.

Key considerations

  • Focus on Proactive Measures: Prioritize improving email sending practices and list quality over attempting to identify individual spam reporters.
  • Monitor Key Metrics: Regularly monitor sender reputation metrics and spam complaint rates to identify and address deliverability issues.
  • Implement Best Practices: Follow email marketing best practices, such as obtaining explicit consent, providing easy unsubscribe options, and sending relevant content.
  • Leverage Aggregated Data: Utilize aggregated spam complaint data from Feedback Loops and Google Postmaster Tools to identify problem areas in email campaigns.
Marketer view

Email marketer from Sender Score indicates that closely monitoring your IP reputation is important. Sender Score analyzes various metrics to determine your sending reputation, and a low score can indicate issues such as high spam complaint rates, although the specific users are not identified.

March 2022 - Sender Score
Marketer view

Email marketer from Email Geeks shares that using the Feedback-ID header may provide some spam complaints per identifier in Google Postmaster Tools (GPT). Deciphering these identifiers may help identify some complainers, although these are just samples, not all complaints.

October 2023 - Email Geeks
Marketer view

Email marketer from HubSpot indicates that implementing a double opt-in process is crucial to improve the quality of your list. You cannot see who marks your emails as spam, instead by having legitimate users who have confirmed their subscription, the chances of being marked as spam are reduced.

March 2024 - HubSpot
Marketer view

Email marketer from Neil Patel emphasizes the importance of monitoring your sender reputation. While you can't directly see who marked your email as spam in Gmail, a sudden drop in sender reputation is a strong indicator of increased spam complaints. Use tools like Google Postmaster Tools (GPT) to monitor reputation and identify potential issues.

February 2022 - Neil Patel
Marketer view

Email marketer from Reddit user u/EmailGuru123 mentions that focusing on email list hygiene is crucial. Remove inactive users and those who haven't engaged in a while. While you can't see who marked you as spam, a cleaner list reduces the likelihood of complaints.

April 2023 - Reddit
Marketer view

Email marketer from Email on Acid shares that regularly cleaning your email list is essential for reducing spam complaints. Removing unengaged subscribers and those who haven't opened or clicked in a while improves your sender reputation, even if you can't identify individual spam reporters.

September 2023 - Email on Acid
Marketer view

Email marketer from Email Marketing Forum user User42 suggests segmenting your email list and sending targeted content to improve engagement. This can help reduce spam complaints, as recipients are more likely to find the content relevant. This will help improve your sender reputation and engagement metrics. This won't directly tell you who marks your emails as spam.

February 2023 - Email Marketing Forum
Marketer view

Email marketer from Mailjet discusses using one-click unsubscribe options and List-Unsubscribe headers as crucial elements for maintaining a healthy sender reputation. Although not directly revealing spam reporters, offering easy unsubscribe options can reduce the likelihood of users marking emails as spam.

June 2022 - Mailjet
Marketer view

Email marketer from Email Marketing Forum user EmailExpert suggests regularly reviewing the content of your emails. Ensure your content is relevant and not misleading. Even if you can't identify specific spam reporters, improving content quality can significantly reduce complaints.

December 2022 - Email Marketing Forum
Marketer view

Email marketer from Reddit user u/EmailPro mentions that using a dedicated IP address will help you monitor the spam rate if you keep the IP address warm, so the reputation will be highly associated with your email practices. You can't see who marked your emails as spam, however you will know your email practices lead to a low or high rate of spam reports.

February 2024 - Reddit

What the experts say
4Expert opinions

While pinpointing specific users who mark emails as spam in Gmail is generally impossible, there are methods to approximate and mitigate spam complaints. Using unique unsubscribe links can offer a fuzzy indication. Structured data strings consistently used in mailings might be identified as FBL identifiers by Google. Feedback Loops (FBLs) provide aggregate data on problematic mailings, enabling you to address issues like list hygiene. However, the primary focus should be on improving sending practices and understanding why recipients are marking emails as spam, rather than identifying individual complainers.

Key opinions

  • No Direct Identification: It's generally not possible to directly identify specific users who mark emails as spam in Gmail.
  • Fuzzy Approximation via Unsubscribe Links: Using unique unsubscribe links can offer an approximate indication of spam complaints, but it is not precise.
  • Structured Data Strings: Consistent structured data strings in mailings can sometimes be identified as FBL identifiers by Google.
  • Aggregate FBL Data: Feedback Loops (FBLs) provide aggregate data on which mailings generate the most spam complaints.
  • Focus on 'Why,' Not 'Who': Efforts should be directed toward understanding and addressing the reasons why recipients are marking emails as spam, rather than attempting to identify individual complainers.

Key considerations

  • Prioritize Improvement: Focus on improving sending practices, such as list hygiene, consent, and relevant content, to reduce spam complaints.
  • Utilize FBLs: Leverage Feedback Loops to identify and address problematic mailings based on aggregate spam complaint data.
  • Actionable Insights: Focus on understanding 'what' campaigns are causing issues rather than 'who' is complaining, as the former is more actionable.
  • Acknowledge Limitations: Acknowledge the limitations of identifying individual complainers and focus on broader strategies for spam complaint mitigation.
Expert view

Expert from Email Geeks shares an example where Google identified an 'L' within a structured data string (message ID or mail identifier) as a FBL identifier because it was consistently present across mailings for a specific list. This was visible in the GPT interface under 'FBL identifiers'. If you have a structured data string and it is consistent across mailings there is a chance that google will pick it up.

May 2021 - Email Geeks
Expert view

Expert from Spamresource.com explains that Feedback Loops (FBLs) are essential for identifying and responding to spam complaints. While FBLs don't reveal individual reporters, they provide aggregate data on which mailings are generating the most complaints. This allows senders to pinpoint problem areas and address them, such as list hygiene or content issues. In essence, focusing on the 'what' (which campaigns are causing issues) is more actionable than the 'who' (individual complainers, which is not provided).

October 2022 - Spamresource.com
Expert view

Expert from Word to the Wise emphasizes that attempting to identify individual users who mark emails as spam is largely futile and often counterproductive. Instead, the focus should be on addressing the underlying issues that lead to spam complaints in the first place. These include ensuring proper list hygiene (removing unengaged subscribers), obtaining explicit consent, sending relevant and valuable content, and making unsubscribing easy. Rather than trying to find 'who' complained, work on 'why' they complained and fix it.

February 2024 - Word to the Wise
Expert view

Expert from Email Geeks explains that using a unique link in the list unsubscribe header can provide an approximation of spam complaints, as Gmail may prompt users to unsubscribe when marking a message as spam. However, it's a fuzzy metric since the list unsub header is present in the mailbox, meaning not every click is a spam complaint.

May 2024 - Email Geeks

What the documentation says
4Technical articles

Identifying individual users who mark emails as spam in Gmail is generally not possible. However, Google Postmaster Tools (GPT), SparkPost and Feedback Loops (FBLs) provide aggregated data on spam complaints, enabling identification of campaigns generating high volumes of complaints. While not revealing individual user details, this allows for targeted investigation and improvement of problematic mailings. Implementing a List-Unsubscribe header as defined in RFC2369 offers an easy opt-out, reducing the likelihood of spam reports. Microsoft also explains how sender reputation is calculated based on spam complaints but it also withholds listing specific complainers.

Key findings

  • No Individual User Identification: It is generally not possible to identify individual users who mark emails as spam.
  • Aggregated Data from GPT: Google Postmaster Tools (GPT) provides aggregated Feedback Loop (FBL) data, allowing senders to identify campaigns with high spam complaint volumes.
  • FBLs Identify Problematic Campaigns: Setting up Feedback Loops (FBLs) with major ISPs like Gmail enables the identification of campaigns triggering high complaint volumes.
  • List-Unsubscribe Header Reduces Spam Reports: Implementing a List-Unsubscribe header, as defined in RFC2369, offers an easy opt-out for users and reduces the likelihood of emails being marked as spam.
  • Microsoft Sender Reputation: Microsoft calculates sender reputation based partly on spam complaints but does not provide a list of the people marking the emails as spam.

Key considerations

  • Focus on Campaign Improvement: Use aggregated data from GPT and FBLs to pinpoint problematic mailings and improve content, targeting, and list hygiene.
  • Implement List-Unsubscribe: Ensure a List-Unsubscribe header is properly implemented to provide an easy opt-out option for recipients.
  • Adhere to Best Practices: Follow email marketing best practices to avoid being placed on blocklists and maintain a positive sender reputation, as per Microsoft's guidance.
  • Data privacy: Services do not provide list of users, it is important to adhere to the user's data privacy and ensure not to collect or solicit this data.
Technical article

Documentation from RFC2369 explains that a List-Unsubscribe header provides a way for users to easily unsubscribe from mailing lists. Although it does not directly help identify users marking emails as spam, it reduces the chance of this happening by enabling users to opt-out easily.

October 2023 - RFC2369
Technical article

Documentation from Microsoft explains how they calculate sender reputation based on spam complaints, among other things. While they don't provide the list of users marking as spam, they advise to follow best practices in order to avoid ending up on blocklists.

February 2023 - Microsoft
Technical article

Documentation from Google explains that Google Postmaster Tools (GPT) can provide aggregated feedback loop (FBL) data, allowing senders to identify campaigns generating high volumes of spam complaints. While it doesn't reveal individual users, it helps pinpoint problematic mailings for investigation and improvement.

January 2022 - Google Postmaster Tools Help
Technical article

Documentation from SparkPost explains that setting up feedback loops (FBLs) with major ISPs like Gmail allows you to receive aggregated data about spam complaints. While it doesn't provide user-level details, it identifies campaigns triggering high complaint volumes so you can address deliverability issues.

October 2021 - SparkPost