How accurate is SNDS and Google Postmaster Tools reputation data?

Key findings

• SNDS inconsistency: SNDS often reports all IPs as 'green' even when deliverability issues are present, leading to a disconnect between the reported status and actual inbox placement.
• Outdated reputation system: Some believe SNDS uses an older reputation engine that hasn't been updated alongside Microsoft's active spam filters, contributing to its inaccuracy.
• GPT as a trailing indicator: Google Postmaster Tools reputation data, particularly for Gmail, is often a trailing indicator, meaning it can take days or even weeks to reflect changes in sending behavior or improvements in reputation.
• Rapid degradation: While GPT reputation can be slow to improve, it can decline very quickly in response to significant negative sending events.
• Slow degradation not reflected: It's possible for deliverability to slowly worsen over months due to sloppy practices while GPT still shows a high reputation, leading to a delayed warning signal.

Key considerations

• Holistic view: Relying solely on SNDS or GPT can be misleading. Always combine these insights with other deliverability metrics and monitoring tools, such as your internal sending logs and complaint rates, to get a complete picture. This helps avoid issues like discrepancies between SNDS and internal reports.
• Lag in data: Be aware that GPT's reputation data may lag behind your actual sending behavior. This means you might experience deliverability issues before they are reflected in the dashboards.
• Proactive monitoring: Do not wait for reputation to tank in these tools. Implement proactive deliverability best practices, including list hygiene and audience engagement, to maintain a healthy sending reputation consistently.
• Understand limitations: Recognize that these tools reflect the recipient's view and are not comprehensive. For instance, Postmaster Tools only provides data for Gmail recipients. For more insights into Google Postmaster Tools, you can refer to Mailgun's guide to understanding sender reputation via GPT.

Key opinions

• SNDS's misleading colors: Many marketers report that SNDS's reputation colors, particularly 'green' across all IPs, often don't reflect actual deliverability performance, suggesting the colors are not reliable indicators.
• Distrust in SNDS data: There's a prevailing sentiment that SNDS's reported reputation is a separate system from the one actually governing inbox placement, leading to a lack of confidence in its utility for real-time diagnostics.
• GPT data lag: Marketers frequently note that Google Postmaster Tools reputation is a 'trailing indicator,' especially when trying to improve a low reputation.
• Rapid drops vs. slow recovery: It's a common observation that Google reputation can drop very quickly during bad sending events, but its recovery (or improvement) is much slower.
• Subtle degradation issues: Marketers have seen deliverability slowly degrade over time due to inconsistent practices, while GPT reputation remains deceptively high, delaying recognition of issues.

Key considerations

• Manage expectations: Understand that SNDS may not always reflect your true standing with Outlook.com, and Google Postmaster Tools can have a significant delay. This is particularly relevant when performing IP warming.
• Combine with other signals: Don't rely solely on these tools. Monitor internal metrics like open rates, click-through rates, bounces, and complaint rates. Also, consider understanding your domain reputation through various lenses.
• Feedback loops are key: Pay close attention to feedback loop data in Google Postmaster Tools, as it directly indicates user complaints, which are strong signals of reputation issues.
• Persistent best practices: Maintain consistent, high-quality sending practices. This includes proper list segmentation, relevant content, and easy unsubscribe options. SendLayer advises leveraging Postmaster Tools data to troubleshoot deliverability problems and address spam complaints promptly.

Key opinions

• SNDS data discrepancy: Experts emphasize that SNDS reputation data is often a separate system from Microsoft's actual inbox placement filters, leading to misleading 'green' reports.
• Aging SNDS engine: A common suspicion is that SNDS's underlying reputation engine is outdated and hasn't kept pace with modern spam filtering advancements.
• GPT's lagging nature: Google Postmaster Tools is widely considered a trailing indicator, providing delayed insights into reputation, which can be challenging for proactive issue resolution.
• Fast drops, slow recovery: Experts acknowledge that while a Google reputation can quickly plummet, its recovery process is typically much slower and less immediate.
• Creator's departure: The fact that SNDS's original creator left Microsoft long ago is sometimes cited as a reason for its perceived lack of modern relevance.

Key considerations

• Contextualize SNDS: While SNDS provides some data, always cross-reference it with actual email delivery rates and feedback loop complaints from Outlook.com users. For more context, see our article on why Outlook.com deliverability is inconsistent and SNDS reliability.
• Patience with GPT: Understand that Google Postmaster Tools data reflects past performance, not instant changes. If you are experiencing fluctuating Gmail Postmaster Tools reputation, consider the delayed nature of the reporting.
• Beyond reported metrics: Focus on foundational deliverability practices (authentication, content quality, engagement) as the primary drivers of reputation, rather than solely reacting to dashboard numbers. Mailgun provides a useful guide on understanding SNDS for sender reputation.
• Active feedback solicitation: The fact that Microsoft has been soliciting feedback on improving SNDS indicates an awareness of its current limitations, suggesting potential future updates.

Key findings

• Google's categorized reputation: Google Postmaster Tools rates domain and IP reputation using qualitative categories (High, Medium, Low, Bad), providing a broad indication of sending quality.
• Detailed GPT dashboards: Google's documentation highlights multiple dashboards, including Spam Rate, IP Reputation, Domain Reputation, Feedback Loop, and Authentication, designed to provide comprehensive insights into Gmail deliverability.
• SNDS provides IP reputation: Microsoft SNDS focuses on IP reputation and provides data like mail volume and complaint rates specific to the Outlook.com network.
• Purpose as troubleshooting tools: Both tools are presented as resources for senders to diagnose and troubleshoot deliverability issues to their respective major mailbox providers.
• Data aggregation: The documentation suggests that data in these tools is aggregated and updated periodically, rather than being a live, real-time feed.

Key considerations

• Verification requirements: To access data in both tools, domains and IPs must be verified, requiring DNS record modifications. This ensures you only see data for properties you own or manage.
• Thresholds for data visibility: Google Postmaster Tools, in particular, requires a significant volume of email to be sent to Gmail recipients before reputation data becomes visible, and it may be intermittent if volume drops. This is a common issue, as discussed in why Google Postmaster data is limited or intermittent.
• Interpreting 'Bad' reputation: Documentation for Postmaster Tools clearly states that 'Bad' reputation indicates a history of sending a very high volume of spam, likely leading to rejection or placement in the spam folder. Knowing what a 'bad' IP reputation means is crucial.
• Focus on specific ISP: Remember that both tools provide data for their respective ecosystems only. They do not offer a universal view of your reputation across all mailbox providers. AWS documentation covers understanding Google Postmaster Tools spam complaints for SES users.