Summary
It can be confusing and frustrating to see your emails land in spam folders when your domain reputation, particularly as reported by tools like Google Postmaster Tools (GPT), appears to be in good standing. While domain reputation is a significant factor in email deliverability, it's not the sole determinant. Mailbox providers (ISPs) use a complex array of signals to decide where an email lands, and a good domain reputation can sometimes mask underlying issues that trigger spam filters.
Key findings
- Razor2 listing: Being listed on a content-based blocklist like Razor2, even if it's considered a 'hobby project' by some, indicates that your email content is exhibiting characteristics that spam filters identify as problematic. While Razor2 itself may not directly cause deliverability issues with major ISPs, it often flags content patterns that other, more influential spam filters also detect.
- Convergent evolution: Different spam filters, including those used by Gmail and Microsoft, can independently arrive at similar conclusions about your email's spamminess (a phenomenon known as convergent evolution). This means that a problem detected by one system, like Razor2, often points to broader content or sending practice issues that affect other filters.
- Beyond domain reputation: Domain reputation, as seen in GPT, primarily reflects your domain's sending history and compliance with authentication standards (like SPF, DKIM, DMARC). However, mailbox providers also heavily weigh other factors, such as IP reputation, content quality, recipient engagement, and subscriber acquisition practices.
- Hidden issues: Low complaint rates or bounce rates can be misleading. If emails are already being routed to the spam or junk folder, recipients are less likely to see or report them. Similarly, efficient bounce handling can keep your bounce rates low, even if you're sending to old or problematic addresses. Mailbox providers, such as Gmail and Microsoft, track a wide range of engagement metrics that may not be visible in your own reporting.
Key considerations
- Content analysis: Focus on the actual content of your emails. Spam filters analyze everything from subject lines and body text to links and images. Generic or overly promotional content, excessive use of spam trigger words, or broken HTML can lead to spam placement, regardless of a good domain reputation.
- Subscriber acquisition: Review your list building practices. If your acquisition methods are not transparent or if subscribers are not explicitly opting in, it can lead to higher spam complaints or low engagement, which negatively impacts your sender reputation over time. Even if you have good domain reputation, issues here can cause problems. For more insights, refer to our guide on why emails to new subscribers go to spam.
- Engagement metrics: Pay close attention to engagement rates (opens, clicks, replies) versus non-engagement (deletes without opening, low read rates). ISPs heavily penalize low engagement, even if spam complaints are low. An email that is consistently ignored by recipients signals to ISPs that it might be unwanted, leading to spam folder placement. You can learn more about this in articles like Why Your Emails Go to Spam.
- Holistic deliverability: Understand that deliverability is a multi-faceted challenge. A good domain reputation is essential, but it must be supported by strong technical configurations, engaging content, and healthy subscriber relationships. For a comprehensive overview, explore our resource on email deliverability issues.
What email marketers say
Email marketers often find themselves perplexed when their emails land in spam, despite diligent efforts to maintain a strong domain reputation. This paradox highlights that while a solid sender reputation is foundational, it doesn't guarantee inbox placement. Marketers frequently encounter scenarios where content issues, list hygiene, or subtle engagement signals override what appears to be a good overall domain standing.
Key opinions
- Content is king (or queen): Many marketers stress that even with good domain health, spammy content—including excessive links, certain keywords, or poor formatting—can trigger filters. It's not just about what you send, but how you present it.
- Engagement matters more: Low engagement (lack of opens, clicks, or prompt deletions) is a strong negative signal, often outweighing a good domain reputation. Marketers find that ISPs interpret this as disinterest, routing emails to spam to protect recipient inboxes. For strategies to improve engagement, see our guide on increasing email click-through rates.
- List quality over quantity: Sending to inactive or unengaged subscribers, even if they never explicitly complain, can degrade your sending reputation. Marketers advise regular list cleaning and focusing on explicit consent to avoid hitting spam traps or generating negative signals.
- IP reputation can differ: While domain reputation is good, the IP address (especially on a shared IP) might have accumulated a poor reputation due to other senders' activities. This can lead to your emails being marked as spam. More on this can be found in discussions like Why Emails Are Going to Spam.
Key considerations
- Segmentation and personalization: Segmenting your audience and personalizing content can significantly boost engagement and reduce the likelihood of emails being marked as spam. Generic sends often perform poorly.
- Sender consistency: Maintain consistent sending volumes and frequencies. Sudden spikes or drops can be perceived as suspicious activity by ISPs, even with a good overall reputation.
- Feedback loops: Actively monitor and respond to feedback loops. Even low complaint rates can indicate underlying issues that need addressing before they escalate. Ensure you're signed up for ISP feedback loops where available.
- Regular testing: Use deliverability testing tools to check your inbox placement across various ISPs regularly. This helps identify issues with content, authentication, or IP reputation before they impact your entire list. While Postmaster Tools are good for domain reputation, tools like GlockApps give more granular inbox placement data.
Marketer view
Marketer from Email Geeks explains their email deliverability challenge. They are seeing that their creatives are being blacklisted in Razor2, a content-based blocklist, according to SpamAssassin feedback. Despite this, their Google Postmaster Tools (GPT) shows a good domain reputation. The marketer notes that emails are still experiencing spam placement in Gmail and Microsoft, as observed through GlockApps. They question whether the Razor2 listing should be a significant concern, especially given the positive domain reputation metrics.
Marketer view
Email marketer from Quora indicates that issues with an email marketing tool's sender reputation can significantly impact deliverability. They explain that if the platform used to send emails has a poor standing, major email providers like Google are prone to flag messages originating from that tool as spam.This highlights that even if your individual domain's reputation is strong, the underlying sending infrastructure's reputation can override it, leading to emails being diverted to spam folders. It underscores the importance of choosing a reputable email service provider.
What the experts say
Deliverability experts consistently point out that a good domain reputation, while essential, is only one component of a healthy sending program. They emphasize that mailbox providers (ISPs) employ sophisticated, multi-layered spam filtering systems that assess numerous factors beyond just the domain's historical standing. Issues like content quality, recipient engagement, and even less prominent blocklists can contribute to spam placement, even when primary reputation metrics appear positive.
Key opinions
- Razor2's limited impact: Experts largely agree that Razor2, despite its listing capabilities, is unlikely to be a direct cause of deliverability problems at major ISPs like Gmail and Microsoft. It's often described as a community or 'hobby' project.
- Convergent filtering: The key takeaway is that if your content triggers Razor2, it's likely the same spammy characteristics are being identified independently by the advanced filters of Gmail and Microsoft. This isn't due to data sharing but rather to common detection algorithms for suspicious content or sending patterns.
- Beyond explicit complaints: High bounce rates and spam complaints are clear indicators of problems. However, experts note that low rates in these areas can be misleading if emails are already being diverted to bulk or spam folders, where recipients are less likely to interact or report. ISPs have internal metrics that capture subtle negative signals not always visible to the sender. This can be complex, and our guide on resolving a low Gmail domain reputation delves deeper.
- Permission is paramount: If an email is hitting a content-based blocklist, it strongly suggests a permission issue, meaning mail is being sent to addresses that never explicitly opted in or are no longer interested. This is a fundamental problem that must be addressed.
Key considerations
- Authentification scrutiny: Even with good domain reputation, misconfigured or failing SPF, DKIM, or DMARC records can lead to spam placement. These technical configurations are foundational for trust. For more detailed insights, refer to our page on DMARC, SPF, and DKIM alignment failures.
- Feedback loops from ISPs: ISPs monitor how users interact with your emails. If users frequently delete emails without opening them, move them to junk, or report them as spam, these actions feed into your reputation score. Experts advise signing up for and actively monitoring ISP feedback loops to catch these signals early. Our guide on understanding DMARC reports can provide more context.
- Content best practices: Experts consistently recommend avoiding spammy content patterns, excessive images, broken links, or misleading subject lines. Even if your sending infrastructure is perfect, poor content can still lead to filtering. This includes not just text, but the overall composition and user experience. Mailchimp's article on How to Avoid Email Spam Filters provides a good starting point.
- Sender behavior: Beyond technical setup, ISPs evaluate sending behavior. This includes sending volume spikes, frequent bounces to invalid addresses (even with bounce handling), and a high proportion of recipients who consistently do not engage with your mail. These behavioral signals can sometimes outweigh a seemingly good domain reputation.
Expert view
Expert from Email Geeks clarifies the role of Razor2 in deliverability. They explain that Razor2 is primarily a community-driven project and is unlikely to be the direct cause of deliverability issues at major mailbox providers like Gmail and Microsoft. However, the expert notes a crucial point: the underlying reasons an email gets listed on Razor2 might be the same factors that Gmail and Microsoft's spam filters are also detecting. This suggests a "convergent evolution" of spam filters, where different systems independently identify similar spammy content or patterns, rather than direct data sharing or code commonality.
Expert view
Expert from SpamResource explains that low spam complaints and bounce rates can be misleading indicators of deliverability health. They suggest that if an email is already being routed to the bulk or spam folder, recipients are far less likely to see it, open it, or report it as spam.This means that a lack of negative feedback doesn't necessarily equate to good inbox placement. It simply might indicate that the messages are not reaching the main inbox to begin with, preventing recipients from registering complaints or bounces. This highlights the importance of monitoring actual inbox placement rather than relying solely on traditional metrics.
What the documentation says
Official documentation from mailbox providers, anti-spam organizations, and industry bodies consistently highlights that email deliverability relies on a multitude of factors. While domain reputation and sender authentication are foundational, content quality, recipient engagement, and compliance with best practices are equally critical. They often describe how various signals are combined to determine inbox placement, explaining why a good domain reputation alone might not prevent emails from being marked as spam.
Key findings
- Multi-faceted filtering: ISPs employ complex algorithms that consider hundreds of signals beyond just domain reputation. These include IP reputation, content analysis, user complaints, engagement metrics, and adherence to technical standards like SPF, DKIM, and DMARC.
- Content quality as a primary signal: Documentation emphasizes that even perfectly authenticated emails from reputable domains can be flagged if their content resembles spam. This includes elements like deceptive subject lines, misleading links, or overly promotional language.
- User engagement: Mailbox providers explicitly state that positive user engagement (opens, clicks, non-deletions) improves reputation, while negative engagement (spam complaints, deletions without opening) harms it. This feedback is critical regardless of domain reputation scores.
- Blocklist diversity: While some blocklists are highly influential, others might be used by specific filters for certain types of content or senders. A listing on a less prominent blocklist can still indicate underlying issues that are also detected by major ISPs, even if the blocklist itself isn't directly consulted by them. For a deeper understanding of these lists, check out our in-depth guide to email blocklists.
Key considerations
- Authentication compliance: Ensure your SPF, DKIM, and DMARC records are correctly configured and pass authentication checks. Mailbox providers like Gmail and Microsoft are increasingly stringent, making proper authentication a prerequisite for inbox placement. Our resource on A simple guide to DMARC, SPF, and DKIM can assist.
- Regular list hygiene: Documentation often advises removing unengaged subscribers and maintaining a clean list to avoid spam traps and reduce negative signals. A continuously healthy list is paramount for long-term deliverability.
- Unsubscribe options: Provide a clear and easy unsubscribe mechanism. This reduces spam complaints, as recipients who no longer wish to receive your emails can opt out gracefully instead of marking your email as spam. This is a common requirement highlighted by many email service providers in their guidelines.
- Monitoring and adaptation: Continuously monitor deliverability performance through various tools and adapt sending strategies based on feedback. Relying solely on one metric (like domain reputation) can provide an incomplete picture. Understanding your email domain reputation from multiple angles is crucial.
Technical article
Documentation from major ISPs (e.g., Google, Microsoft) states that while proper authentication via SPF, DKIM, and DMARC is fundamental, it does not guarantee inbox placement. They emphasize that these protocols verify sender identity but do not inherently vouch for content quality or sender behavior. An email can be authenticated correctly and still be marked as spam if other signals indicate it is unwanted.This highlights the layered approach of modern spam filters, where technical compliance is a necessary but not sufficient condition for successful email delivery.
Technical article
Anti-spam documentation for tools like SpamAssassin explains that collaborative filtering systems, such as Razor2, collect and share checksums of spam messages. A listing on such a system indicates that the content of your email has been identified by other users or systems as spam.While not all blocklists are used universally by all ISPs, a pattern match on a system like Razor2 signals that your content has problematic characteristics that could be recognized by other, more influential spam filters, even if they use different detection mechanisms.
Related resources
14 resources
Related pages
How to resolve a low Gmail domain reputation?
Why do emails from new domains go to spam with low sending volumes?
Why do my emails go to spam due to DMARC, SPF, and DKIM alignment failures?
Why are emails to new subscribers going to spam while existing list deliverability remains good?
Email Deliverability Issues: Getting Your Messages to the Inbox in 2025
Why Your Emails Are Going to Spam in 2024 and How to Fix It
How to Increase Email Click Through Rate [Step By Step Guide]
An in-depth guide to email blocklists
A practical guide to understanding your email domain reputation
A simple guide to DMARC, SPF, and DKIM
