Summary
The question of whether Google Postmaster Tools (GPT) aggregates domain reputation data across a root domain and its subdomains is a common point of confusion for email senders. While Google provides a unified platform to monitor various sending metrics, the way it calculates and displays domain reputation can be nuanced. Generally, Google tends to treat subdomains as distinct entities for reputation purposes, especially when they are used for different sending streams. However, there are instances where data for the root domain might appear to encompass or influence its subdomains, leading to mixed interpretations.
Key findings
- Distinct reputations: Google Postmaster Tools often assigns individual reputation scores to specific subdomains, meaning that a subdomain can have a different reputation than its parent domain.
- Authentication alignment: Domain reputation within GPT is heavily tied to the specific domain used in DKIM and SPF authentication. If emails are signed with a subdomain, its reputation will be tracked separately.
- Root domain overview: While specific subdomains maintain their own scores, adding the root domain to GPT can provide an aggregated view of traffic and reputation across all its subdomains in certain dashboards, as stated by some deliverability guides.
- Impact on deliverability: Poor performance on one subdomain (e.g., high spam rates) can negatively affect the overall perception of the parent domain and its other subdomains, even if their reputations are technically separate.
Key considerations
- Add all sending domains: To get the most accurate and comprehensive data, it is best practice to add every subdomain you use for sending to Google Postmaster Tools individually.
- Monitor distinct metrics: Pay close attention to the reputation and spam rate metrics for each individual subdomain, as this will provide the most actionable insights into your sending health.
- Isolate sending types: Using separate subdomains for different types of emails (e.g., transactional, marketing, notifications) can help mitigate the risk of one stream negatively impacting another.
What email marketers say
Email marketers often find the interaction between root domain and subdomain reputation in Google Postmaster Tools to be a complex and sometimes contradictory area. Their experiences range from assuming a unified reputation to being explicitly told by Google that subdomains are entirely separate. The practical observations highlight the need for careful monitoring of all sending domains.
Key opinions
- Mixed aggregation views: Some marketers initially assume that Google Postmaster Tools aggregates subdomain data into the root domain's reputation, while others report receiving direct communication from Google suggesting the opposite.
- Observation of inconsistency: Marketers note that GPT sometimes displays a reputation for a root domain even when no emails are sent directly from it, leading to questions about how that reputation is derived or influenced by subdomains. This highlights the complexities of Google's tracking mechanisms.
- Focus on DKIM: There's a general tendency among marketers to prioritize the DKIM signing domain (d= tag) when assessing reputation, as this seems to be Google's primary identifier for attributing sending activity.
Key considerations
- Complaint rates are critical: A high complaint rate (e.g., 25%) on any sending domain or subdomain is a clear indicator of a poor reputation and will significantly impact deliverability.
- FBL identifier insights: Marketers trying to understand the nuances often look to how Google uses FBL (Feedback Loop) identifiers, suggesting that even if subdomains are included in a root calculation, they might be segmented for reporting.
- Verify your understanding: Marketers should not rely on assumptions about how GPT handles subdomains. It's crucial to set up and monitor all relevant domains in their GPT account and observe the data directly.
Marketer view
Marketer from Email Geeks suggests that the root domain reputation in Google Postmaster Tools appears to be a combined score, incorporating email sent from both the root domain itself and any associated subdomains.
Marketer view
Marketer from Email Geeks observes that Google Postmaster Tools may include subdomain data in the root calculation, potentially separating it via FBL identifiers, though the exact mechanism can be unclear.
What the experts say
Email deliverability experts generally concur that Google Postmaster Tools (GPT) primarily assesses reputation at the specific domain or subdomain level from which emails are authenticated and sent. While a parent domain might show an overall reputation, the most granular and actionable data typically comes from monitoring each individual sending subdomain. Experts also highlight that reputation is dynamic and can change rapidly, especially for new sending domains.
Key opinions
- Separate reputation scores: Experts frequently observe that parent domains and their subdomains often have completely different reputation scores within GPT.
- Dynamic reputation: A domain, even a new one, might initially show a 'high' reputation in GPT, but this can degrade very quickly once email sending begins, emphasizing the importance of initial sending practices.
- DKIM/SPF importance: The specific domain (or subdomain) that passes DKIM or SPF authentication is what Google primarily uses to attribute reputation. Therefore, each unique sending subdomain (with its own DKIM/SPF setup) develops its own reputation.
Key considerations
- Monitor all sending entities: For comprehensive deliverability management, it's crucial to add and monitor every distinct subdomain (and the root domain) that sends email via Google Postmaster Tools.
- Proactive reputation management: Don't wait for a reputation drop to act. Regular monitoring of each sending subdomain's metrics is essential for maintaining strong deliverability.
- Understand the full picture: While individual subdomain reputations are key, understand how overall domain health (and IP reputation) can be influenced by poor sending practices across any part of your email infrastructure.
Expert view
Expert from Email Geeks has observed distinct reputation scores in Google Postmaster Tools for parent domains compared to their subdomains, indicating they are often treated independently for reputation assessment.
Expert view
Expert from Email Geeks warns that while new domains may show high reputation initially in Google Postmaster Tools, this can rapidly change once they begin sending email, underscoring the dynamic nature of reputation.
What the documentation says
Official documentation and authoritative guides on Google Postmaster Tools often present slightly varied perspectives on subdomain reputation aggregation. Some imply a degree of aggregation when the root domain is added, while others emphasize the distinct reputation of specific sending subdomains, particularly those tied to DKIM and SPF authentication. This divergence highlights the complexity of Google's internal algorithms and the need for senders to consider both individual and overarching domain health.
Key findings
- Exact domain focus: Many documentation sources specify that the Domain Reputation dashboard in Google Postmaster Tools focuses on messages sent from the exact domain used for DKIM and SPF authentication.
- Separate calculation: Several sources explicitly state that the reputation of the root domain and its subdomains are calculated separately, reinforcing the idea of distinct scores.
- Aggregated view possibility: Conversely, some documentation indicates that adding the top-level or root domain can provide aggregated traffic data across all its subdomains within Postmaster Tools, suggesting a broader overview.
Key considerations
- Individual subdomain monitoring recommended: Despite potential aggregation, best practices from documentation recommend adding and monitoring each specific subdomain to gain granular insights into their performance and reputation.
- Primary domain verification: Documentation confirms that verification of the primary domain is often a prerequisite for adding and monitoring its subdomains in Google Postmaster Tools.
- No sub-domain compliance: Some sources suggest there isn't a specific 'sub-domain level compliance' concept from Google, implying a broader assessment linked to the primary domain when a subdomain is viewed.
Technical article
Documentation from Iterable states that the Domain Reputation dashboard is not currently present in the Google Postmaster Tools V2 interface, and furthermore, subdomains are considered distinct from the primary sending domain.
Technical article
Documentation from SocketLabs indicates that there is no concept of sub-domain level compliance with Google; therefore, when a subdomain (like marketing.example.com) is viewed, it still relates to the primary domain's data.
Related resources
15 resources
Related pages
Does subdomain data roll up to the root domain in Google Postmaster Tools?
How does Google Postmaster Tools track domain reputation and handle subdomains?
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How much does subdomain reputation affect core domain reputation?
How does parent domain reputation affect subdomain deliverability and sender reputation?
Will using a subdomain for different email types affect my primary domain's reputation?
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