Summary
A sudden spike in your transactional email spam rate can be perplexing, especially when other email streams perform well and your sender reputation appears solid. This guide delves into common reasons behind unexpectedly high spam rates for transactional emails, particularly those sent to Gmail, and outlines practical troubleshooting steps.
Key findings
- Gmail FBL data: Gmail does not provide traditional Feedback Loop (FBL) data to ESPs like SendGrid, meaning an ESP will not report spam complaints from Gmail users. The sole source for Gmail spam complaints is Google Postmaster Tools.
- Subdomain visibility: If you are using a subdomain for transactional emails but only your main domain is registered in Google Postmaster Tools, you may not have granular insight into which mailstream is generating the complaints. Registering transactional DKIM subdomains in Postmaster Tools is crucial for accurate troubleshooting.
- Complaint attribution: Google states that spam rates in Postmaster Tools are attributed to the day an email was sent, not the day a complaint was made. However, this behavior does not always align with observed patterns, making troubleshooting days with no sends but high complaints challenging.
- Low volume impact: For low sending volumes (e.g., 300-400 emails/day), even a small number of spam complaints can significantly inflate the percentage spam rate. This percentage might look high but could represent a minimal raw number of complaints.
- External factors: New or unmonitored sending activities, such as those from sales teams using external tools, can inadvertently affect your domain's reputation, even if they send to different email domains. While not directly to Gmail, such activities can still influence overall sender reputation.
Key considerations
- Verify Postmaster Data: Always consult Google Postmaster Tools for accurate spam complaint data directly from Gmail. Relying solely on ESP reports for Gmail complaints will give you an incomplete picture.
- Subdomain registration: Register all subdomains used for sending email, especially transactional ones, in Google Postmaster Tools. This helps isolate the source of any issues and understand the specific reputation of each mailstream.
- Review send patterns: Analyze your sending logs against Postmaster Tools data. If complaints appear on non-sending days, consider whether users are reporting older emails as spam, or if there's a delay in Google's reporting.
- Segmentation: Distinguish between marketing and transactional email sending domains. Using separate domains or subdomains helps maintain distinct reputations and prevents issues with one stream from affecting the other.
- Low volume interpretation: When dealing with low email volumes, focus on the raw number of complaints rather than just the percentage. A low raw number with a high percentage might not be as impactful on your sender reputation as it appears.
What email marketers say
Email marketers frequently face challenges with transactional email deliverability, often observing discrepancies between their ESP's reported metrics and those from major mailbox providers like Gmail. Understanding these differences is key to effective troubleshooting. Marketers highlight that while marketing emails might show excellent engagement and low spam rates, transactional emails can unexpectedly land in spam folders, even when technical configurations appear correct.
Key opinions
- Data discrepancy: Many marketers note that their ESP reports zero spam complaints for transactional emails to Gmail, while Postmaster Tools indicates a high spam rate. This disparity is a common source of confusion.
- Consistent high performance: Even with generally excellent email metrics for marketing campaigns (e.g., high open rates, low spam rates), transactional emails can still experience isolated spikes in spam flagging.
- Unexpected fluctuations: A sudden high spam rate over a few days, especially when no major campaigns were sent, points to underlying issues that are not immediately obvious.
- Impact of auxiliary sends: Some believe that unmonitored sending activities from other departments, even at low volumes and to different email providers, might indirectly contribute to reputation issues affecting transactional emails.
- Postmaster Tools for insights: Marketers recognize Google Postmaster Tools as the authoritative source for Gmail spam complaint data, essential for identifying and troubleshooting issues not reported by their ESPs.
Key considerations
- Monitor all sending activities: Be aware of all email sending sources within your organization, including those from sales or business development teams, as they can collectively impact your domain's sending reputation. While seamlessAI is not a direct threat to transactional mail if it's on a different domain, it highlights the importance of keeping track of all sending practices.
- Distinguish email types: Recognize that transactional emails have different expectations from recipients than marketing emails. Their content and context should be strictly informative and necessary, avoiding any promotional elements that could trigger spam complaints. Read more about the importance of transactional emails.
- Review Postmaster Tools data: Regularly check your domain's spam rate in Google Postmaster Tools. This is your most reliable source for Gmail-specific complaint data, which your ESP might not provide.
- Understand domain reputation impact: Even with separate subdomains, the overall domain reputation can be influenced by issues on any subdomain. Poor practices on one subdomain can affect others.
Marketer view
An email marketer from Email Geeks reports that their transactional emails to Gmail users suddenly saw an above 2.5% spam rate for four days, despite nearly perfect performance in the preceding 30 days.
Marketer view
An email marketer from Email Geeks notes that they send about 300-400 transactional emails daily to Gmail users, yet their SendGrid reports show zero spam complaints for these emails, creating a puzzling discrepancy.
What the experts say
Email deliverability experts offer critical insights into the nuances of Gmail's spam reporting, distinguishing it from traditional FBLs. They highlight common pitfalls, such as the inability to segment complaint data if different mailstreams share the same DKIM domain, and the speculative nature of troubleshooting due to Google's data opacity. Experts also emphasize that factors like email volume can dramatically skew reported spam percentages.
Key opinions
- Gmail FBL absence: Experts confirm that Google does not operate a traditional Feedback Loop, which explains why ESPs cannot report Gmail spam complaint data directly.
- Postmaster Tools as sole source: The only reliable place to view Gmail spam complaints is within Google Postmaster Tools.
- DKIM domain segmentation: If marketing and transactional emails share the same DKIM domain, it becomes impossible to differentiate between their respective spam complaints in Postmaster Tools.
- Root causes: Common causes for high spam rates include problematic sign-ups leading to spam reports, issues with DKIM replay, or emails getting filtered directly to spam folders.
- Volume sensitivity: For low sending volumes, a small number of complaints can result in a disproportionately high percentage, which may not indicate a severe reputation problem.
- Gmail's opacity: Due to the lack of transparency from Google regarding its internal mechanisms, diagnosing and troubleshooting deliverability issues often involves a degree of speculation.
Key considerations
- Register subdomains: To gain clear insights into the performance of specific mailstreams, especially transactional ones, ensure that their DKIM subdomains are registered in Google Postmaster Tools.
- Understand complaint attribution: While Google states that complaints are attributed to the day of send, observed behavior can differ. If complaints appear on non-sending days, consider delayed reporting or user action on older emails.
- Contextualize complaint rates: A 0% complaint rate without the context of inbox placement can be misleading; it might indicate poor deliverability rather than good performance.
- Consider legal implications: Experts suggest that Google's reluctance to share certain complaint data, particularly from Google Workspace users, may stem from legal considerations regarding customer data ownership.
Expert view
An expert from Email Geeks confirms that Google does not have a traditional Feedback Loop (FBL), which means SendGrid, or any other ESP, will not display complaint data originating from Gmail.
Expert view
An expert from Email Geeks reiterates that Gmail does not utilize a traditional FBL, and therefore, SendGrid's lack of complaint data for Gmail is accurate; the only place to find such data is within Google Postmaster Tools.
What the documentation says
Official documentation and authoritative sources provide foundational knowledge for understanding transactional email deliverability and high spam rates. They clarify how email service providers (ESPs) and mailbox providers (MBPs) assess sender reputation, the expected benchmarks for complaint rates, and the technical mechanisms used to identify and filter spam. These resources are critical for implementing best practices and resolving deliverability challenges.
Key findings
- Sender reputation scrutiny: ESPs and spam filters closely evaluate a sender's reputation and engagement metrics. A poor reputation can lead to emails being flagged as suspicious, even if legitimate.
- Spam complaint thresholds: Industry standards suggest that the total spam complaint rate should ideally remain below 0.03% of total transactional emails sent to ensure good deliverability.
- Postmaster Tools feedback: Google Postmaster Tools offers a feedback loop feature that helps identify which specific Job IDs or campaigns are experiencing high spam rates in Gmail.
- Authentication importance: Implementing proper email authentication protocols like SPF, DKIM, and DMARC is fundamental for reducing spam complaints and improving sender trustworthiness.
- Content relevance: Transactional emails must be strictly functional and relevant to the user's action, avoiding promotional content that could trigger spam filters.
Key considerations
- Adhere to standards: Ensure your spam complaint rate remains well below industry benchmarks, preferably below 0.03%, to maintain optimal deliverability and avoid being blacklisted or blocklisted.
- Use dedicated IPs: For high-volume transactional sends, consider using a dedicated IP address to maintain separate sending reputations and prevent issues from affecting other email types.
- Maintain content focus: Keep transactional emails concise and directly related to the user's interaction. Promotional content can confuse recipients and lead to spam reports, regardless of authentication.
- Implement DMARC: Properly configure and monitor your DMARC record to ensure strong email authentication and to receive valuable feedback on email delivery and authentication failures.
Technical article
SMTP.com documentation emphasizes that email service providers and spam filters rigorously examine a sender's reputation and engagement metrics, which are crucial for effective email delivery.
Technical article
Spotler documentation states that the cumulative spam markings (or complaints) for transactional emails should ideally never exceed 0.03% of the total volume sent, indicating a tight industry standard.
Related resources
15 resources
![Top 6 Transactional Email Best Practices [See Them Now!]](https://www.socketlabs.com/wp-content/uploads/2019/04/marketing_email_example.png)
![Why Are My Emails Going To Spam? [100% Fix] - Email Warmup](https://emailwarmup.com/blog/wp-content/uploads/2024/08/Why-Are-My-Emails-Going-To-Spam_11zon.jpg)
Related pages
Why are transactional emails suddenly going to spam at Gmail?
How to troubleshoot transactional emails going to spam despite good Postmaster data?
How to troubleshoot transactional emails going to spam?
Why are my transactional emails going to spam?
Ultimate guide to Google Postmaster Tools v2
Why your emails are going to spam in 2024 and how to fix it
What causes high spam complaint rates in Gmail, and how can they be fixed?
A simple guide to DMARC, SPF, and DKIM
A practical guide to understanding your email domain reputation
Why are transactional emails with passing SPF, DKIM, and DMARC landing in spam?
