What tools are essential for comparing two sending domains?

While Gmail Postmaster Tools is free and offers valuable insights for Gmail , you'll also need to leverage data from your Email Service Provider (ESP) or marketing automation platform for engagement metrics like opens, clicks, and complaints. Consider third-party deliverability tools for advanced inbox placement testing and blocklist monitoring .

How do I identify which domain is underperforming?

A significantly higher spam rate or lower domain reputation in Postmaster Tools for one domain is a clear indicator. Additionally, a lower open rate, higher complaint rate, or increased bounce rate from your ESP can signal underperformance. Check authentication failures reported in DMARC reports for specific causes.

Is email authentication important for comparing domains?

Yes, ensure both domains have correct SPF, DKIM, and DMARC records in their DNS . Misconfigurations in these authentication protocols are a common reason for poor deliverability and can skew your comparison results. They are foundational to building and maintaining a good sender reputation.

How much do engagement metrics matter for Gmail?

Absolutely. Google prioritizes user engagement. Even if your technical setup is perfect, if users aren't opening, clicking, or are marking your emails as spam, it will negatively impact your domain's reputation and deliverability. Compare open rates, click rates, and complaint rates across domains in your ESP's reports.

What is the impact of a blocklist on my sending domains?

If a domain is listed on a blacklist (or blocklist), it means it has been flagged as a source of spam or malicious activity. This can severely hinder your email deliverability, causing emails to be rejected or sent directly to spam folders by many mailbox providers, including Gmail . Use a blocklist checker to see if your domain is listed.

How can I compare the success of two different sending domains in Gmail? - Tools - Email deliverability - Knowledge base

When managing email programs, it's common for businesses to use multiple sending domains. Perhaps you've separated transactional emails from marketing communications, or you're testing different strategies across brands. A critical question then arises: how do these domains perform individually, especially within a dominant mailbox provider like

Gmail? Understanding the success of each domain is vital for maintaining a healthy sender reputation and maximizing deliverability.

Comparing two different sending domains in Gmail requires a multi-faceted approach. It goes beyond simple open rates, delving into technical configurations, user engagement patterns, and the feedback Gmail provides. By systematically analyzing these aspects, you can pinpoint strengths and weaknesses, allowing you to optimize your email strategy for each domain.

Understanding Google Postmaster Tools

One of the most direct ways to gauge your domain's performance with Gmail is through Google Postmaster Tools. This free service offers invaluable insights into how Google perceives your sending domains. You can add and verify multiple domains, allowing you to view their individual metrics side by side. It's crucial to set up each domain in Postmaster Tools to get a clear, distinct picture of their performance.

Key dashboards within Postmaster Tools include Spam Rate, IP and Domain Reputation, Feedback Loop (FBLs), and Authentication (SPF, DKIM, DMARC). The Spam Rate dashboard is particularly insightful as it directly reflects how many of your messages are being marked as spam by users and Gmail’s filters. You want this rate to be as low as possible for both domains, ideally below 0.1%. A sudden spike for one domain could indicate a content issue or a list hygiene problem.

The Domain Reputation and IP Reputation dashboards show you how Gmail (and other mailbox providers, by extension) views the trustworthiness of your sending entities. A Good reputation means your emails are likely to reach the inbox, while a Bad or Low reputation indicates severe deliverability challenges. If one domain consistently shows a lower reputation than the other, it signals a deeper issue that needs immediate attention, perhaps a blacklist or blocklist entry.

Metric	Domain A (Transactional)	Domain B (Marketing)
Spam Rate	0.05%	0.4%
Domain Reputation	High	Medium
Delivery Errors	Minimal	Authentication failures

Deep diving into engagement metrics

Beyond the technical data provided by Postmaster Tools, user engagement plays a significant role in how Gmail judges your domains. Gmail's algorithm heavily weighs how recipients interact with your emails. This means you need to look at metrics like open rates, click-through rates, reply rates, and crucially, spam complaint rates from your Email Service Provider (ESP) or marketing automation platform. While Postmaster Tools gives you the Gmail perspective, your ESP provides the full picture of user interaction across all mailbox providers.

To effectively compare, segment your ESP data by sending domain. This allows you to track specific engagement trends for each. For instance, if one domain has a significantly higher spam complaint rate, even if its Postmaster Tools reputation looks okay, it indicates an audience relevance problem or an issue with the content itself. Conversely, high open rates and low unsubscribe rates on one domain suggest a healthy and engaged list.

When analyzing these metrics, always consider the purpose of each domain. A transactional domain might have lower engagement rates overall, but you'd expect near-perfect inbox placement and very low complaint rates. A marketing domain might have higher engagement but a slightly elevated complaint rate is sometimes expected. The goal is to identify discrepancies that aren't explained by the email type. For more insights on improving your rates, check out our guide on how to troubleshoot and improve low Gmail deliverability.

Best practices for email engagement

Segmentation: Send relevant content to targeted segments to increase opens and clicks.
Content quality: Ensure your email content provides value and meets recipient expectations.
List hygiene: Regularly remove inactive or unengaged subscribers to improve overall deliverability.
Frequency: Avoid over-sending, which can lead to increased complaints and unsubscribes.

Ensuring proper authentication and infrastructure

A fundamental aspect of email deliverability, especially when comparing multiple domains, is ensuring proper technical authentication. Gmail and Yahoo's new sender requirements for bulk senders have made SPF, DKIM, and DMARC non-negotiable. If one of your sending domains consistently underperforms the other, a deep dive into its authentication setup should be your next step.

Ensure that both domains have valid and correctly configured SPF records that authorize all your sending IPs. Verify that DKIM signatures are properly signed and aligned with your sending domain. Most importantly, implement a DMARC policy with at least a p=none policy for both domains to receive aggregate reports, which are invaluable for identifying authentication failures. If one domain is failing DMARC alignment, it's a clear reason for lower deliverability (or even emails going to the junk folder).

The consistency of your authentication is key. Even minor misconfigurations can cause email servers (including Gmail's) to view your emails with suspicion. Regularly review your DNS records for any discrepancies between the two domains. Look for differences in SPF includes, DKIM selectors, or DMARC policies that might explain performance variations. This foundational work is non-negotiable for comparing domain success reliably.

Example DMARC record (for monitoring)dns

v=DMARC1; p=none; rua=mailto:dmarc_reports@yourdomain.com; ruf=mailto:dmarc_forensics@yourdomain.com; sp=none; adkim=r; aspf=r;

Advanced monitoring and testing

While Google Postmaster Tools is excellent for high-level domain reputation, it doesn't always provide the granular, real-time insights needed for direct comparison of different sending domains or troubleshooting specific issues. For a more comprehensive view, especially when one domain is underperforming, you'll need to use advanced monitoring and testing methods.

This involves using inbox placement tests with seed lists. You send identical (or very similar) emails from both domains to a diverse seed list that includes addresses across major mailbox providers, including Gmail. The results will show you precisely where your emails land (inbox, spam, promotions, missing) for each domain. This real-time data helps you identify subtle differences in filtering that Postmaster Tools might not capture immediately.

Additionally, blocklist monitoring is critical. While not always directly tied to Gmail's internal reputation, being on a major public blacklist or blocklist can severely impact deliverability across the board, including with Gmail. If one domain suddenly sees a drop in performance, check if its IP or domain (or both) has landed on a public blocklist. This proactive monitoring allows you to identify and address issues before they significantly damage your sending reputation for either domain.

Common pitfalls

Ignoring DMARC reports: Failing to analyze aggregate and forensic reports can mask authentication failures.
Focusing solely on open rates: This metric can be unreliable and doesn't tell the full deliverability story.
Neglecting list hygiene: Sending to unengaged or invalid addresses hurts domain reputation over time.
Inconsistent sending volume: Spikes or sudden drops can negatively impact how ISPs perceive your sending patterns.

Views from the trenches

Best practices

Maintain distinct content strategies for each domain, aligning with their purpose.

Regularly clean your email lists to remove inactive or unengaged subscribers for both domains.

Segment your audience precisely for each domain to ensure high engagement and relevance.

Implement strong authentication: SPF, DKIM, and DMARC with enforcement policies.

Monitor Google Postmaster Tools daily for both domains to catch issues early.

Common pitfalls

Sending inconsistent volumes across domains, which can trigger spam filters.

Ignoring DMARC reports, missing vital authentication failure insights.

Not segmenting email types (transactional vs. marketing) onto separate domains.

Failing to warm up new sending domains or IP addresses properly.

Overlooking feedback loops, leading to high complaint rates.

Expert tips

Use subdomains for different email streams to manage reputation more granularly.

Focus on maintaining extremely low spam complaint rates across all domains, ideally below 0.1%.

Monitor your open and click rates as proxies for engagement, but remember Gmail uses its own metrics.

Regularly review your DNS records for SPF, DKIM, and DMARC to ensure they are correctly configured and aligned.

Invest in consistent list cleaning and re-engagement campaigns to keep your subscriber base healthy.

Expert view

Expert from Email Geeks says that comparing sending domains involves analyzing existing reporting for opens, clicks, bounces, unsubs, and spam reports for each domain.

2024-07-03 - Email Geeks

Marketer view

Marketer from Email Geeks says they typically extract both reports, drop them into Excel or Google Sheets, and apply calculations to see side-by-side performance.

2024-07-04 - Email Geeks

Maximizing your sending domain performance

Comparing the success of two different sending domains in Gmail is a continuous process that requires attention to detail across multiple data sources. By diligently monitoring Google Postmaster Tools, analyzing engagement metrics from your ESP, ensuring robust email authentication, and leveraging advanced testing, you can gain a clear understanding of each domain’s performance. This granular insight empowers you to make data-driven decisions, troubleshoot issues proactively, and ultimately maximize the deliverability and effectiveness of your email program.

Remember, small differences in performance between domains can often be attributed to subtle variations in sending patterns, list quality, or even content. Consistent monitoring and a proactive approach to maintain your sender reputation will ensure both your sending domains perform optimally with Gmail and other mailbox providers.