Does subdomain data roll up to the root domain in Google Postmaster Tools?

Key findings

• Data aggregation: Google Postmaster Tools aggregates subdomain data into the root domain's reports, especially for overall compliance and reputation metrics.
• Subdomain visibility: To see detailed data for a specific subdomain, you must add and verify that subdomain directly within Google Postmaster Tools. Once the root domain is verified, adding subdomains typically does not require new DNS verification records.
• Primary domain focus: The GPT dashboard primarily provides status for primary domains, but this status is influenced by all associated subdomains, as noted by EmailLabs.
• Reputation impact: Poor performance (e.g., high spam rates) on a subdomain can negatively impact the reputation of the overall root domain, highlighting the interconnectedness of domain and subdomain health. More on this is available in our guide on how Google Postmaster Tools tracks domain reputation.

Key considerations

• Setup best practices: It's advisable to set up Google Postmaster Tools for your primary domain first, as this often allows for automatic inclusion of subdomains. For detailed guidance, consult our article on setting up Gmail Postmaster Tools for subdomains.
• Data latency: Google Postmaster Tools data is not real-time; typically, it has a delay of up to two days. This means any changes or new sending activity may not be reflected immediately.
• Thresholds for data: To see data, domains and subdomains must meet Google's minimum email volume requirements. Low sending volumes may result in no data appearing in the dashboards.
• Authentication: Ensure all sending domains and subdomains are properly authenticated with SPF, DKIM, and DMARC to ensure data appears and to maintain good deliverability.

Key opinions

• Direct observation: Many marketers confirm that data from subdomains does roll up to the root domain in GPT, often noticing changes in the root domain's reputation after introducing or altering subdomain sending.
• Subdomain-specific insights: Despite the roll-up, marketers strongly advise adding subdomains individually to GPT if they want to monitor the specific performance and troubleshoot issues unique to that subdomain.
• Verification process: There's a common understanding that once the root domain is verified in GPT via a DNS record, subsequent subdomains typically do not require additional DNS verification records to appear in the tool, simplifying setup. Our guide on how to verify a domain in GPT provides more detail.
• Data delay expectations: Marketers often caution clients about a delay in data population for new subdomains, suggesting a waiting period of a few days before expecting to see comprehensive reports.

Key considerations

• Granular monitoring: For comprehensive deliverability management, marketers should add all significant sending subdomains to Google Postmaster Tools, even if data seems to roll up. This allows for specific insights into spam rates and IP reputation for each sending source.
• Client communication: When onboarding new subdomains or domains in GPT, set clear expectations with clients regarding the 2-day data delay, preventing immediate concerns about missing data.
• Authentication consistency: Ensure that all subdomains use consistent and proper SPF, DKIM, and DMARC authentication, as issues with these can prevent data from appearing in GPT or negatively impact sender reputation. Learn more about how subdomain spam complaints affect root domain reputation.
• Troubleshooting verification: If GPT asks for a TXT record for a subdomain when the root is already verified, investigate whether the subdomain has its own pre-existing Google verification that might be causing a conflict or specific requirement.

Key opinions

• Hierarchical data view: Experts agree that if the root domain is properly set up and verified in GPT, any subdomain associated with that root or organization domain will display data, contributing to the parent domain's overall metrics.
• Data lag: It's commonly noted by experts that GPT data typically lags by about two days from the current date. Senders should account for this delay when analyzing recent sending performance.
• Conditions for data display: For data to appear in GPT dashboards, experts stress the necessity of meeting certain criteria, including minimum email volume, proper DKIM signing, and successful domain verification. Without these, no data will be displayed.
• Authentication importance: Proper email authentication (SPF, DKIM, DMARC) for both root and subdomains is critical. DMARC, for instance, is set up at the root and its policy extends to all subdomains, influencing how Google processes their mail. Learn more in our guide to DMARC, SPF, and DKIM.

Key considerations

• Comprehensive monitoring strategy: Experts recommend monitoring both the root domain and key subdomains separately in Google Postmaster Tools. This provides a holistic view of email program health while allowing for drill-down analysis into specific sending streams. Our article on whether to monitor top-level and DKIM subdomains dives deeper.
• Volume consistency: Maintain consistent sending volumes from subdomains to ensure they meet the thresholds for data reporting in GPT. Erratic or very low volumes might result in insufficient data for meaningful analysis.
• Reputation alignment: Understand that the reputation of your root domain is intrinsically linked to its subdomains. A decline in subdomain reputation can pull down the overall domain reputation, impacting deliverability across all sending entities.
• Proactive troubleshooting: Given the data delay, experts advise proactive monitoring of sending practices and early identification of issues on subdomains to mitigate potential negative impacts on the root domain's reputation before they are fully reflected in GPT.

Key findings

• Compliance reporting: Google Postmaster Tools utilizes subdomain data to determine compliance metrics, even though the dashboard mainly provides status for primary domains. This implies that subdomain performance is an integral part of the root domain's overall score.
• Simplified setup: Setting up Google Postmaster Tools for your primary domain first is often suggested as a best practice, as this action can automatically allow you to add and see data for all associated subdomains. This is highlighted by Iterable's blog.
• Domain and subdomain relationship: Subdomains are structurally tied to the root domain, often defined as a combination of the hostname and the root domain itself. This fundamental relationship dictates how their data is viewed and aggregated by tools like GPT, as explained by Customer.io's documentation.
• DMARC policy application: DMARC policies are typically set up at the root domain level and automatically apply to all subdomains. This unified policy enforcement means that deliverability outcomes across subdomains can directly influence the root domain's reputation as seen by receivers like Google.

Key considerations

• Holistic view: Documentation implies that while specific subdomain data can be accessed, the overall health and compliance status derived from Google Postmaster Tools reflects the combined performance of the root domain and its subdomains.
• Verification flow: Be aware that if a subdomain has its own pre-existing Google verification (e.g., for Google Search Console), it might still require a separate TXT record for Postmaster Tools verification, even if the root is verified.
• Impact of negative signals: Any negative signals, such as high spam rates or low engagement, originating from a subdomain are likely to be factored into the root domain's overall reputation score within Postmaster Tools, potentially affecting all sending from that domain family.
• Data aggregation strategy: Documentation suggests that Google's aggregation strategy is designed to provide a cohesive view of an organization's sending reputation, making it essential to monitor all sending entities under a single domain.