Does Gmail prioritize domain or IP reputation, and how does IP warming apply?
Michael Ko
Co-founder & CEO, Suped
Published 17 Jun 2025
Updated 16 Aug 2025
7 min read
When sending emails, one of the most common questions is how mailbox providers, especially Gmail, assess your sending reputation. Does Gmail prioritize your domain's reputation or the IP address from which your emails originate? It's a nuanced question, and the answer isn't a simple either/or scenario.
Understanding how Gmail weighs different reputation factors is crucial for ensuring your emails land in the inbox, not the spam folder. While Google doesn't fully disclose the intricacies of its filtering algorithms, observations and statements from Google employees suggest a sophisticated approach that evaluates multiple signals.
This leads us to IP warming, a fundamental process in email deliverability. If both domain and IP reputation are important, how does IP warming fit into the picture, especially when you're introducing new sending infrastructure? Let's explore the dynamics of Gmail's reputation system and the strategic application of IP warming.
The dual pillars of Gmail reputation
Gmail's filtering system considers a combination of factors to determine email deliverability. It's not about one factor completely overshadowing the other, but rather a holistic assessment where both domain and IP reputation play distinct, yet interconnected, roles. Google employees have clearly stated that transitioning to new IPs requires warming up new resources.
Domain reputation is increasingly recognized as the primary long-term indicator of a sender's trustworthiness. It's tied to your domain's historical sending patterns, adherence to best practices, and overall engagement from recipients. This includes proper authentication protocols like SPF, DKIM, and DMARC. A strong domain reputation can often provide a buffer, but it doesn't completely negate the need for a good IP reputation.
IP reputation (or sender IP reputation), on the other hand, is directly linked to the specific IP address used for sending emails. It reflects the immediate sending behavior from that IP, including volume, bounce rates, spam complaints, and any presence on email blocklists or blacklists. Even if your domain has an excellent reputation, a new or poorly managed IP can still lead to deliverability issues.
Here's a breakdown of how these two key factors interact:
Domain reputation impact
Credibility: A positive domain reputation signals trustworthiness to Gmail, indicating a legitimate sender with consistent sending practices.
Portability: Your domain's reputation is more enduring. It stays with you even if you switch ESPs or IP addresses.
Foundation: It lays the groundwork for how your emails are perceived, often influencing the initial trust given to new IPs associated with your domain.
The critical role of IP warming
IP warming (or IP address warm-up) is the process of gradually increasing the volume of emails sent from a new IP address. The goal is to build a positive sending history and establish trust with internet service providers (ISPs), including Gmail, by demonstrating legitimate sending behavior over time. When you start sending from a new IP, it has no prior sending history, essentially a neutral reputation. ISPs are cautious about new IPs sending large volumes of mail immediately, as this behavior often characterizes spammers.
Even with a strong domain reputation, you still need to warm up new IPs. Think of it as introducing a new employee to a trusted company. The company (your domain) has a great reputation, but the new employee (your IP) still needs to prove themselves reliable. Sending too many emails too quickly from a new IP can trigger spam filters and lead to immediate deliverability issues, regardless of your domain's standing. This is particularly relevant when migrating to a new email service provider or adding dedicated IPs.
Failure to properly warm up an IP can result in your emails being throttled, delayed, or sent directly to the spam or junk folder. It can also lead to your IP being placed on a blacklist (or blocklist), making it very difficult to reach your recipients. This is why a strategic warming plan is essential, even if your domain reputation is already stellar.
With a strong domain reputation
Domain trust: Your existing positive domain reputation provides a foundation of trust for new IPs.
Smoother start: ISPs may be slightly more lenient with initial volumes due to the trusted domain.
Still essential: Gradual warming is still crucial to build a unique, positive IP history.
Skipping IP warm-up
High risk: Sending large volumes immediately can trigger spam filters and blacklists.
Reputation damage: Can negatively impact both your new IP and potentially your established domain reputation.
Deliverability issues: Leads to emails being blocked, throttled, or sent to spam.
Key factors influencing Gmail's algorithm
Beyond domain and IP reputation, Gmail's algorithms also heavily weigh recipient engagement. This includes how your subscribers interact with your emails: opens, clicks, replies, and whether they mark your emails as spam or delete them without opening. High engagement signals positive reputation, while low engagement or high complaint rates can quickly damage your standing. Even during IP warming, monitoring unsubscribe rates and soft bounces is vital.
Spam complaints are a direct and severe negative signal. Every time a recipient marks your email as spam, it significantly degrades your reputation. Similarly, a high hard bounce rate indicates poor list hygiene and can negatively affect both your domain and IP reputation. Maintaining a clean, engaged email list is paramount for long-term deliverability.
Proper email authentication is the bedrock of good deliverability. SPF (Sender Policy Framework), DKIM (DomainKeys Identified Mail), and DMARC (Domain-based Message Authentication, Reporting & Conformance) records verify that your emails are legitimately sent from your domain and haven't been tampered with. Gmail heavily relies on these authentication signals to determine if an email is trustworthy. Without them, even a stellar IP and domain reputation might not be enough to reach the inbox.
Factor
Description
Impact on Gmail deliverability
Domain reputation
Historical trust of your sending domain, including authentication.
Primary long-term indicator. Strong domain reputation can mitigate initial IP issues but doesn't eliminate IP warming.
IP reputation
Sending history and behavior of the specific IP address.
Crucial for new IPs and direct sending. Poor IP reputation leads to blocks/throttling, even with good domain reputation.
User engagement
Opens, clicks, replies, marks as spam, deletions without opening.
Foundational. Essential for verifying sender legitimacy and preventing spoofing. Non-compliance leads to inbox placement issues.
Best practices for sustained deliverability
To ensure your emails consistently reach the inbox, a multi-faceted approach is required. First, focus on maintaining an exceptionally clean and engaged email list. Remove inactive subscribers regularly, promptly process unsubscribes, and avoid sending to purchased or old lists. This helps minimize bounces and spam complaints, which are critical for both IP and domain health.
Secondly, consistently monitor your sender reputation using tools like Google Postmaster Tools. This provides insights into your domain and IP reputation, spam rate, and authentication errors, helping you identify and address issues proactively. For instance, you can see how your domain reputation is performing over time, which directly impacts deliverability to Gmail accounts.
Finally, adhere to a strict IP warming schedule whenever introducing new IPs. This gradual ramp-up allows ISPs to observe your sending habits and gradually assign a positive reputation to your new infrastructure. Combine this with relevant content, clear opt-in processes, and easy unsubscribe options to foster good engagement and maintain high deliverability rates.
Tips for optimal deliverability
Segment your lists: Send to your most engaged subscribers first during IP warming.
Monitor feedback loops: Act quickly on spam complaints to maintain a clean sender reputation.
Consistent sending: Maintain a consistent sending volume and frequency after warming.
Views from the trenches
Best practices
Always follow recommended IP warming schedules for new IPs, even with an established domain.
Prioritize email list hygiene to minimize bounces and spam complaints and protect reputation.
Implement strong email authentication (SPF, DKIM, DMARC) for all sending domains.
Monitor your sender reputation metrics closely via Google Postmaster Tools.
Segment your email lists and send highly relevant content to boost engagement.
Common pitfalls
Sending large volumes immediately from a new IP, leading to throttling or blocklisting.
Ignoring IP reputation because domain reputation is strong, causing deliverability issues.
Not maintaining a clean email list, resulting in high bounce and spam complaint rates.
Neglecting email authentication, which makes emails appear suspicious to ISPs.
Failing to adapt sending strategies based on Postmaster Tools feedback and warnings.
Expert tips
Consider how Google's system aggregates various reputation signals for a comprehensive sender profile.
Understand that even with great domain reputation, new IPs need to prove themselves trustworthy.
Recognize that temporary failures (tempfails) on new IPs during warming can indicate IP reputation building.
Focus on the 'tuple' of sending reputation, which includes the combination of domain and IP.
Be aware that while domain reputation is paramount, a new IP still requires a dedicated warm-up period.
Expert view
Expert from Email Geeks says that Google looks at both domain and IP reputation, so you need to warm up new IP and domain combinations, even if your domain already has a good reputation.
2023-03-27 - Email Geeks
Marketer view
Marketer from Email Geeks says that it's a misconception to think that Gmail solely focuses on domain reputation. If you're starting with new IPs, you absolutely need to warm them up just like any other provider.
2023-03-27 - Email Geeks
Achieving inbox success
While industry consensus and anecdotal evidence suggest Gmail places significant emphasis on domain reputation, it's clear that IP reputation remains a vital component of its filtering decisions. The idea that you can simply rely on a strong domain reputation to bypass IP warming for new infrastructure is a false dichotomy.
For optimal email deliverability, particularly with Gmail, a comprehensive strategy is essential. This includes diligently warming up new IP addresses, rigorously maintaining your sending domain's reputation, ensuring proper authentication, and consistently prioritizing recipient engagement. By addressing all these factors, you enhance the likelihood of your emails reaching the inbox and achieving your marketing goals.
authentication protocols like SPF, DKIM, and DMARC. A strong domain reputation can often provide a buffer, but it doesn't completely negate the need for a good IP reputation.
spam or delete them without opening. High engagement signals positive reputation, while low engagement or high complaint rates can quickly damage your standing. Even during IP warming, monitoring unsubscribe rates and soft bounces is vital.
