Summary
A flat or zero feedback loop (FBL) graph in Google Postmaster Tools (GPT) is a frequent observation for email senders and is typically a positive sign. This indicates that your email campaign either has a low sending volume to Gmail or, more commonly, that the rate of user-reported spam is below Google's internal, undisclosed thresholds. The FBL graph specifically tracks direct 'report spam' clicks made by Gmail users, not general user actions like moving emails to junk. While often signaling a strong sender reputation and low complaint volume, a persistently flat graph could, in some cases, suggest potential inbox placement issues where emails are consistently landing in the spam folder, thus avoiding explicit user complaints. Google's FBL data is aggregated and does not reflect every single complaint; it is displayed only when specific volume and complaint thresholds are met, and Google may prioritize providing this data to senders it deems trustworthy.
Key findings
- Common and Positive: A flat or zero feedback loop (FBL) graph in Google Postmaster Tools (GPT) is a common occurrence and is often a positive indicator, signifying excellent email performance with very few recipients marking emails as spam.
- Volume and Complaint Thresholds: The primary reasons for a flat FBL graph are either insufficient email sending volume or a spam complaint rate from Gmail users that falls below Google's specific, undisclosed minimum thresholds-for example, a complaint-to-delivery ratio lower than 0.4%.
- Direct Gmail Complaints: GPT's FBL data specifically tracks explicit 'report spam' actions by Gmail users directly within the Gmail interface; simply moving an email to junk or deleting it does not contribute to this data.
- Sample, Not All Data: The FBL data provided by Google is not a 1:1 reflection of all actual complaints and represents only a sample. Google aggregates this data and may not display anything if the number of complaints is too low to meet its internal reporting requirements.
- Sender Trustworthiness: Historically, Google has provided FBL data primarily to senders deemed trustworthy who are expected to investigate their practices, and a flat graph might suggest that Google does not consider the sender trustworthy enough to provide the data, or that complaints are simply too low.
Key considerations
- Volume vs. Complaints: Assess your email sending volume to Gmail; a flat graph is a common and expected outcome for senders with low volume or extremely low complaint rates.
- Inbox Placement: While a flat FBL graph is often positive, consistently zero spam complaints coupled with low open rates might indicate that your emails are going directly to spam, bypassing user complaints.
- Authentication Protocols: Ensure that essential email authentication protocols, such as SPF, DKIM, and DMARC, are correctly configured, as this can impact whether Google Postmaster Tools consistently populates data.
- Engagement and List Hygiene: Focus on maintaining high recipient engagement and a clean mailing list to naturally keep complaint rates below Google's reporting thresholds, leading to a flat FBL graph.
- Thresholds and Trust: Understand that Google only displays FBL data when specific volume and complaint rate thresholds are met, and it may prioritize providing this data to senders deemed trustworthy.
What email marketers say
14 marketer opinions
The frequent observation of a flat or zero feedback loop (FBL) graph in Google Postmaster Tools (GPT) is typically a positive sign, indicating very low spam complaint rates from Gmail users that fall below Google's internal, undisclosed thresholds. This can persist for weeks, even for high-volume senders. While often reflecting excellent email performance, a persistently flat graph coupled with low open rates might suggest a hidden inbox placement issue where messages are consistently routed to the spam folder without generating explicit user complaints. It is crucial to understand that GPT's FBL data specifically tracks direct 'report spam' clicks within Gmail and is not a 1:1 reflection of all complaints; a blank graph simply means insufficient data to display, not necessarily zero complaints. Furthermore, correct configuration of email authentication protocols like SPF, DKIM, and DMARC is vital for Google Postmaster Tools to consistently populate any data.
Key opinions
- Widespread Observation: A flat or zero feedback loop (FBL) graph in Google Postmaster Tools (GPT) is a very common observation for email senders and can persist for weeks, even for those sending high volumes of mail.
- Threshold-Driven Display: The primary reason for a flat FBL graph is that the number of direct spam complaints from Gmail users falls below Google's minimum internal thresholds required to display data, such as a complaint-to-delivery ratio under 0.4%.
- Positive Performance Indicator: In most instances, a flat FBL graph signals strong email performance, indicating excellent sender reputation and very few recipients actively marking messages as spam within Gmail.
- Specific Complaint Tracking: GPT's FBL specifically tracks explicit 'report spam' actions initiated by Gmail users directly through the Gmail interface; other actions, like simply deleting an email or moving it to junk, do not contribute to this data.
- Sampled and Threshold-Based Data: Google does not provide all actual spam complaints, nor does it offer direct FBLs; the displayed data is a sample, and a blank graph means there are insufficient complaints to meet Google's display criteria, not necessarily an absolute zero.
- Authentication as Prerequisite: Proper configuration of essential email authentication protocols like SPF, DKIM, and DMARC is a foundational requirement for Google Postmaster Tools to consistently populate and display any feedback data.
- Volume Anecdote: Anecdotal evidence suggests that consistent FBL data in Google Postmaster Tools may only appear for senders who reach extremely high email volumes, potentially millions of emails daily.
Key considerations
- Monitor Beyond FBL: While a flat FBL graph is often a positive sign, consistently low open rates alongside a zero or flat FBL should prompt an investigation into potential inbox placement issues, as emails might be bypassing the inbox and landing directly in spam folders.
- Ensure Domain Access: Confirm that you have successfully verified and have proper domain access within Google Postmaster Tools to view your feedback loop graphs and other relevant data.
- Validate Authentication: Regularly verify that your email authentication protocols-SPF, DKIM, and DMARC-are correctly configured and aligned, as this is critical for Google Postmaster Tools to consistently provide any data.
- Sustain High Engagement: Continuously strive for high recipient engagement and rigorous list hygiene, as these practices are key to keeping spam complaint rates below Google's reporting thresholds, resulting in a healthy, typically flat, FBL graph.
- Understand Data Nuances: Recognize that a blank or flat FBL graph does not equate to zero complaints, but rather that the complaint volume is below Google's display threshold, and the data provided is always a sampled portion, not a complete count.
Marketer view
Email marketer from Email Geeks explains that users with domain access on Google Postmaster Tools (GPT) should see the feedback graph. He also clarifies that a flat graph often means insufficient complaints from Gmail users, as the data is not a 1:1 reflection of all complaints. He suggests that consistently zero spam complaints and low open rates in GPT might indicate an inbox placement issue where messages are going to spam.
18 Jul 2022 - Email Geeks
Marketer view
Email marketer from Email Geeks confirms that Feedback Loop (FBL) data in Google Postmaster Tools (GPT) is frequently flat.
4 Feb 2025 - Email Geeks
What the experts say
2 expert opinions
When the feedback loop (FBL) graph in Google Postmaster Tools (GPT) appears flat or registers zero, it generally signifies that recipients are not marking your emails as spam. This positive indication means your complaint rate is either genuinely very low, potentially rounded down to zero by Google's aggregated data reporting, or that your mail volume to Gmail users is below the threshold required for data display. Google's FBL specifically reports actual spam complaints from direct Gmail deliveries, not forwarded mail or general user feedback. Therefore, a flat line often points to strong deliverability and a positive sender reputation.
Key opinions
- Low Complaint Rate: A flat or zero FBL graph primarily indicates an exceptionally low, or even non-existent, spam complaint rate from Gmail recipients.
- Volume Dependency: Google Postmaster Tools only provides FBL data for senders with a significant volume of mail to Gmail; insufficient volume will result in a flat or absent graph.
- Actual Spam Reports: The data displayed on the FBL graph reflects explicit 'report spam' actions by users, rather than other interactions like 'not spam' clicks or general email forwarding.
- Data Aggregation: Google aggregates FBL data, meaning very low complaint rates can be rounded down or appear as zero, even if a few isolated complaints occurred.
- Direct Delivery Focus: FBL data is specific to mail directly delivered to Gmail users, not to mail that might have been forwarded or interacted with indirectly.
Key considerations
- Positive Deliverability: A flat FBL is largely a good sign, affirming that your email program is performing well with minimal user complaints.
- Assess Mail Volume: Always consider your sending volume to Gmail; if it is low, a flat FBL is expected and does not necessarily indicate zero complaints.
- Focus on Inbox Placement: While positive, ensure your emails are actually reaching the inbox, as a flat FBL coupled with low open rates could suggest mail is going to spam and thus bypassing explicit complaints.
- Maintain List Health: Continue prioritizing list hygiene and sending relevant content to engaged subscribers, which inherently keeps complaint rates low and contributes to a flat FBL.
Expert view
Expert from Spam Resource explains that a flat or zero Google Postmaster Tools feedback loop graph can occur if the complaint rate is genuinely very low or if the complaints are for mail not sent directly to Gmail users (e.g., forwarded mail). Google's FBL data is aggregated, and a low rate might be rounded down to zero. The data specifically reflects actual complaints, not just 'not spam' clicks.
6 Feb 2022 - Spam Resource
Expert view
Expert from Word to the Wise explains that a flat or zero Google Postmaster Tools feedback loop graph is generally a positive sign, indicating that recipients are not marking your emails as spam. She notes that GPT only provides data for senders with significant mail volume to Gmail; if volume is too low, no data will be displayed, leading to a flat graph. The reported data represents actual spam complaints, not just general user feedback.
22 May 2023 - Word to the Wise
What the documentation says
6 technical articles
The flatness or absence of data in the Google Postmaster Tools feedback loop (FBL) graph indicates that your email program is likely performing well, with Gmail users rarely marking your messages as spam. This state is common and suggests that either your sending volume to Gmail is below the threshold for data display, or, more positively, that your spam complaint rate is so low it falls beneath Google's undisclosed minimum reporting requirements. It specifically reflects direct 'report spam' actions by Gmail users.
Key findings
- Volume or Complaint Rate: The primary reasons for a flat or zero FBL graph are either insufficient email sending volume to Gmail or a spam complaint rate that falls below Google's specific, undisclosed thresholds.
- Positive Reputation Indicator: A flat FBL often serves as a positive indicator of good sender reputation and low complaint volume, suggesting that Gmail users are not actively marking emails from your domain as spam.
- Threshold-Based Reporting: Google Postmaster Tools only displays FBL data when both the email volume and the number of user-reported spam complaints meet certain undisclosed minimum thresholds.
- Gmail-Specific Complaints: This graph exclusively tracks explicit 'report spam' actions initiated by Gmail users within the Gmail interface, not general user feedback or complaints from other providers.
- Common for Healthy Lists: This flat state is a common observation for new senders or those who maintain highly engaged and clean mailing lists, naturally resulting in a lack of reportable spam complaints.
Key considerations
- Generally Positive Outlook: While seemingly absent data, a flat FBL graph is typically a positive sign, reflecting a healthy email program that successfully avoids triggering user-reported spam.
- Review Sending Volume: Always consider your sending volume to Gmail; if it is low, a flat FBL graph is the expected outcome and does not necessarily indicate zero complaints.
- Evaluate Inbox Placement: Despite a positive FBL, a flat graph paired with low open rates might suggest emails are consistently landing in the spam folder, thus bypassing user complaints and warranting further investigation into inbox placement.
- Prioritize List Quality: Continue to emphasize rigorous list hygiene and highly engaging content to naturally keep spam complaint rates low, which contributes to a flat and healthy FBL graph.
- Understand Data Requirements: Be aware that Google only populates FBL data when its internal volume and complaint thresholds are met, meaning a flat graph often signifies that these reporting requirements have not been reached.
Technical article
Documentation from Google Postmaster Tools Help explains that a flat or zero feedback loop (FBL) graph indicates that the sender is either sending a low volume of emails or has a low rate of user-reported spam. Significant email volume and a considerable number of spam reports are prerequisites for data to appear in the FBL graph.
23 Nov 2024 - Google Postmaster Tools Help
Technical article
Documentation from Postmark explains that a flat FBL graph signifies either an insufficient email sending volume or a lack of spam complaints that reach Google's specific, undisclosed thresholds. It highlights that this data exclusively tracks spam reports made by Gmail users.
16 Dec 2022 - Postmark Blog
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