Do I need to re-warm up my IP when changing domain extension?
Michael Ko
Co-founder & CEO, Suped
Published 26 Jun 2025
Updated 15 Aug 2025
6 min read
When managing email deliverability, questions often arise about how specific changes impact your sending reputation. One common scenario is altering your domain extension, for instance, moving from example.com to example.net. It might seem like a minor adjustment, but it can have significant implications for your email program.
The core of the matter revolves around how mailbox providers perceive your sending identity. While you might retain the same brand name and even the same IP address, a change in your Top-Level Domain (TLD) effectively creates a brand new sender in the eyes of most internet service providers (ISPs).
The impact of a TLD change on sender reputation
Understanding how email systems identify senders is crucial here. Domain extensions like .com, .net, or .org are formally known as Top-Level Domains (TLDs). When you change your domain from yourdomain.com to yourdomain.net, you are essentially moving to an entirely separate domain from a technical standpoint. ISPs and recipient mailbox providers will treat yourdomain.net as a completely new, unknown entity.
This is because email reputation is primarily tied to the sending domain, not just the IP address. While IP reputation still plays a role, major mailbox providers like Google and Yahoo have shifted their focus significantly towards domain reputation. They monitor metrics like spam complaints, bounces, and engagement rates associated with your domain to determine whether your emails should land in the inbox or the spam folder. For more on this, you can check Google's email sender guidelines.
Even if your underlying IP address remains the same and has a stellar reputation, the new domain extension carries no historical sending data. It starts with a neutral, or even suspicious, reputation. Automated filtering systems employed by ISPs are highly sophisticated and do not automatically associate different TLDs of the same domain name as belonging to the same sender.
The primary reason for needing to re-warm your sending setup (which includes the new domain) is to establish a positive sender reputation from scratch. Without a proper warm-up, your emails sent from the new domain extension are highly likely to encounter deliverability issues.
Mailbox providers rely on historical sending data and engagement metrics to trust a sender. A new domain has none of this, making it appear suspicious. Sending large volumes too quickly from a cold domain can trigger spam filters, leading to your emails being marked as spam or even your domain being placed on an email blocklist (or blacklist). To understand more about this, you can review Mailgun's guide on domain warm-up.
Beyond deliverability, a poor reputation can also impact your brand's trustworthiness. Recipients who consistently find your emails in their spam folders may lose trust in your brand, leading to lower open rates, click-through rates, and ultimately, reduced ROI from your email campaigns. This highlights the critical importance of a strong email domain reputation.
You also need to ensure all your email authentication records (like SPF, DKIM, and DMARC) are correctly configured for the new domain extension. These records are fundamental for proving your legitimacy as a sender. Without them, even a warm IP address won't guarantee inbox placement, as your emails will lack essential trust signals.
Importance of authentication
New DNS records: Each domain, including one with a new TLD, requires its own SPF, DKIM, and DMARC records to be set up in its DNS. This is independent of the IP address.
Verification: Mailbox providers use these records to verify that emails coming from your new domain are legitimate. Without proper setup, your messages are more likely to be flagged as suspicious.
Consistency: Ensure your return-path and DKIM signing domain match your new sending domain to achieve DMARC alignment, which is critical for good deliverability.
Implementing a successful domain warm-up
The process of warming up a new domain extension is very similar to warming up any other new domain. It involves gradually increasing your sending volume over a period, allowing ISPs to build a positive reputation for your new domain based on positive engagement signals. This measured approach is key to avoiding spam filters and ensuring your emails reach their intended recipients. Learn more about warming up a new IP address in SparkPost's warm-up overview.
Begin by sending small volumes to your most engaged subscribers, who are highly likely to open and click your emails. As engagement rates remain strong and bounce rates stay low, you can gradually increase your daily sending volume. Monitor your deliverability closely using tools like Google Postmaster Tools to track your reputation, spam complaints, and any potential blocklist (or blacklist) listings.
The duration of the warm-up process varies based on your sending volume and list quality, but it typically ranges from a few weeks to a couple of months. Rushing the process can be detrimental, leading to deliverability issues that are harder to recover from. Patience and consistent monitoring are vital for success. You can see more about duration in Grazitti's article on IP warming.
Remember, the goal is to show mailbox providers that you are a legitimate sender who sends desired content. This applies equally when warming a new sending domain on an existing IP or when changing a domain extension. Every change to your primary sending domain requires a careful and strategic warm-up approach.
Factor
Old TLD (e.g., .com)
New TLD (e.g., .net)
Sender reputation
Established historical reputation built over time with Outlook, Gmail, etc.
Starts with neutral or zero reputation, treated as an unknown sender by ISPs.
Authentication records
SPF, DKIM, DMARC records already configured and published in DNS.
Requires new SPF, DKIM, and DMARC record setup in its DNS for proper authentication.
Deliverability impact
Relies on established good standing for inbox placement.
High risk of emails landing in spam or being blocked without proper warming.
Start with very low sending volumes to your most engaged segments.
Gradually increase volume, monitoring engagement and bounce rates.
Segment your audience based on engagement for the warm-up period.
Ensure all email authentication (SPF, DKIM, DMARC) is correctly set up for the new TLD.
Actively monitor your new domain's reputation using Postmaster Tools and blocklist checks.
Common pitfalls
Sending high volumes immediately, leading to spam folder placement.
Neglecting to configure SPF, DKIM, and DMARC for the new domain.
Ignoring bounce rates and spam complaints during the warm-up.
Not segmenting lists, sending to unengaged users first.
Assuming your existing IP reputation transfers fully to the new TLD.
Expert tips
Use a subdomain for sending initially to protect the main brand domain.
Focus on positive engagement during the warm-up; avoid cold outreach.
Consider a phased rollout, sending transactional emails first, then marketing.
Keep the old domain active for a transition period to catch misdirected emails.
Automated warm-up services can help manage the gradual volume increase.
Marketer view
A marketer from Email Geeks says that a domain extension change results in a brand new domain with zero reputation in the eyes of recipient mailbox providers, so warming is necessary.
2020-06-30 - Email Geeks
Expert view
An expert from Email Geeks notes that automated filtering systems do not attempt to aggregate different TLDs, treating them as distinct entities.
2020-06-30 - Email Geeks
Final thoughts on TLD changes and warm-up
In conclusion, yes, you absolutely need to re-warm up your sending domain when changing its extension, even if your IP address remains the same. The new domain extension (or TLD) is perceived as a completely new sender by mailbox providers, initiating its reputation from scratch. This process is critical for maintaining high email deliverability and avoiding spam filters.
By following a structured warm-up plan, gradually increasing volume, and diligently monitoring your sender reputation, you can successfully transition to your new domain extension without compromising your email program's performance. Remember, a proactive approach to email deliverability is always the most effective strategy.
Google and 
Yahoo have shifted their focus significantly towards domain reputation. They monitor metrics like spam complaints, bounces, and engagement rates associated with your domain to determine whether your emails should land in the inbox or the spam folder. For more on this, you can check Google's email sender guidelines.
Outlook, 
Gmail, etc.
