How long does it take to warm up a new sending domain?

A new sending domain typically requires a warm-up period ranging from a few weeks to several months, depending on your sending volume and list engagement. It's not a fixed timeline; it depends on how quickly ISPs build trust in your new domain based on positive sending behavior. Small daily increases are key.

What happens if I don't warm up my new sending domain?

If you do not properly warm up your new sending domain, ISPs will likely flag your emails as suspicious. This can result in a significant portion of your emails being sent to spam folders, rejected outright, or your domain being added to blacklists (or blocklists), severely impacting your email deliverability.

Can I use my old domain and new domain at the same time during the transition?

Yes, it is often recommended to use both the old and new domains simultaneously during the transition period. You can gradually shift a percentage of your sending volume from the old domain to the new one, allowing for a smoother warm-up and minimizing disruption to your audience. This strategy is part of the best approach for transitioning email sending .

Is it okay to change my IP address and sending domain simultaneously?

It is generally advised to avoid changing both your IP address and sending domain at the same time. Each change introduces a new element for ISPs to evaluate, making it harder to identify the source of any deliverability issues. Ideally, keep your IP consistent if possible while warming up the new domain, or warm up one element at a time.

What are the best practices for switching to a new sending domain? - Sender reputation - Email deliverability - Knowledge base

Switching to a new email sending domain is a significant step that can profoundly impact your email deliverability and sender reputation. It is far more than just changing a name in your 'From' field; it is essentially introducing a completely new identity to email service providers (ISPs) and your subscribers.

Without proper planning and execution, this transition can lead to a drastic drop in inbox placement, increased spam complaints, and even domain blacklisting (or blocklisting, if you prefer). I will outline the best practices to ensure a smooth transition and maintain your hard-earned sender reputation.

Understanding domain reputation and why it matters

When you switch to a new sending domain, it starts with a neutral or unknown reputation. This is similar to a new IP address, where ISPs have no historical data to evaluate its trustworthiness. Consequently, new domains are often viewed with suspicion, and mail sent from them might be subjected to stricter filtering.

Every aspect of your email, from the visible 'From' address to the underlying DKIM signature and Return-Path (bounce) domain, is tied to your sending domain. Even the URLs within your email content that link back to your website can be evaluated in relation to your sending domain. A consistent and trustworthy domain identity across all these elements is crucial for building and maintaining a positive sender reputation.

Ignoring this newness can lead to significant deliverability problems. ISPs may route your emails to spam folders, or your domain could end up on an email blacklist (or blocklist), preventing your messages from reaching their intended recipients altogether. Understanding what happens when your domain is blacklisted is a critical part of this process.

Pre-transition essentials

Before you even consider hitting send from your new domain, thorough preparation is crucial. This involves not only internal alignment but also proactively communicating with your audience. Display a banner on your old website, send out a series of announcement emails, and use social media to inform subscribers about the upcoming change. This helps them recognize emails from the new domain, reducing the chances of them marking your messages as spam.

A crucial, yet often overlooked, step is email list hygiene. Before migrating any contacts to your new sending domain, clean your email lists. Remove inactive subscribers, known spam traps, and invalid email addresses. Sending to a clean, engaged list from the start will significantly improve your new domain's reputation.

Considerations for the old domain

Subscriber awareness: Notify your audience in advance about the domain change.
Reputation maintenance: Continue sending high-quality, engaged traffic from the old domain during the transition period.
Link redirects: Set up 301 redirects for any links from the old domain that might still be active in past emails or on your website.

Building the new domain's trust

DNS authentication: Properly configure SPF, DKIM, and DMARC for the new domain.
Gradual volume: Start with low sending volumes and slowly increase them over time.
Consistent content: Send high-quality, engaging content to foster positive recipient interactions.

Consider your subdomain strategy. Many email deliverability experts recommend using subdomains for different types of email streams, such as marketing.yourdomain.com and transactional.yourdomain.com. This isolates the reputation of each sending stream, protecting your primary domain from potential issues. To learn more about this, check out our guide on choosing an email sending domain.

If you are also migrating to a new email service provider simultaneously, the process becomes even more intricate. Ensure your existing ESP allows for a smooth transition of DNS records and that you can manage the changeover without disrupting your current sending volume from the old domain during the ramp-up phase of the new domain.

Implementing technical configurations

Technical setup is paramount for the success of your new sending domain. You must configure essential email authentication records, including SPF, DKIM, and DMARC. These records act as digital signatures, verifying that your emails are legitimate and preventing unauthorized parties from sending emails on your behalf (spoofing). For a comprehensive overview, review Google's email sender guidelines.

DNS record essentials

SPF: Authorizes sending IP addresses that are allowed to send email on behalf of your domain.
DKIM: Provides a digital signature that verifies the sender's identity and ensures the message hasn't been tampered with.
DMARC: Specifies how recipient mail servers should handle emails that fail SPF or DKIM validation. Setting up a DMARC record is essential.
Alignment: Ensure proper alignment of all authentication protocols with your new sending domain. For more info, see this simple guide to DMARC, SPF, and DKIM.

Example DNS records for a new sending domainDNS

v=spf1 include:_spf.example.com ~all
h=From:Subject:Date:Message-ID:Content-Type:MIME-Version
v=DKIM1; k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDnQdD
v=DMARC1; p=none; rua=mailto:reports@yourdomain.com

Pay close attention to your Return-Path domain, also known as the bounce domain or mail path. This domain is critical for handling bounces and often carries its own reputation that needs to be properly configured and aligned with your new sending domain. You can learn more in our guide on changing an email's Return-Path domain.

Verify all settings rigorously. A single misconfigured DNS record can severely impact deliverability, leading to your emails being rejected, sent to junk folders, or failing authentication checks.

The strategic warm-up process

The domain warm-up process is non-negotiable for a new sending domain. It involves gradually increasing your email volume over a period to build trust with internet service providers (ISPs). Starting with high volumes immediately is a common pitfall and will almost certainly result in a poor sender reputation. This principle is widely recognized, as detailed in the M3AAWG Sending Domains Best Common Practices.

The risk of skipping warm-up

Attempting to send large volumes of email from a brand-new domain without a proper warm-up will almost certainly lead to emails being blocked or landing in the spam folder. ISPs view sudden spikes from unknown domains as highly suspicious, triggering their spam filters.

Start your warm-up by sending to your most engaged subscribers, as this generates positive engagement signals. Gradually expand to larger, less engaged segments. Monitor your sending metrics closely, such as open rates, click-through rates, bounce rates, and spam complaint rates. These metrics provide invaluable insights into how ISPs are perceiving your new domain. For more in-depth guidance, see our articles on warming up a new domain on an existing warmed IP and warming a new domain for cold contacts.

Day	Max volume	Audience focus
Days 1-3	500-1,000	Most engaged subscribers (e.g., opened/clicked in last 30 days)
Days 4-7	2,000-5,000	Engaged segments (e.g., opened/clicked in last 90 days)
Days 8-14+	Gradual increase	Broader segments, avoiding unengaged contacts initially

Continuously check if your new domain has landed on any blocklists (or blacklists). Being listed means your emails are likely being rejected, potentially causing significant deliverability issues. If listed, take immediate action to delist and rectify the underlying issues. Regularly monitoring your domain's reputation with tools like Google Postmaster Tools is also crucial during this phase. You can use our blocklist checker to monitor your status.

Views from the trenches

Best practices

Gradually ramp up sending volume from the new domain to build trust.

Avoid switching IP addresses at the same time as changing domains for a smoother transition.

Carefully ramp up traffic to the new domain by starting with your most engaged subscribers.

Common pitfalls

Treating a new sending domain like an established one by sending high volumes immediately.

Attempting to switch over all email sending uses to the new domain simultaneously.

Underestimating the time and effort required for a proper domain warm-up.

Expert tips

Ensure you understand all email components that are affected by a domain switch, including the visible From address, Return-Path, DKIM signature, and links within the message.

Prepare for a meticulously careful ramp-up process to avoid triggering spam filters and safeguard your sender reputation.

It is generally easier to warm up a new domain on an existing warmed IP address than to warm up both a new domain and new IPs concurrently.

Marketer view

Marketer from Email Geeks says that as far as ISPs are concerned, a new domain will have all the associated issues of a fresh start, so it is best to avoid switching IPs at the same time and instead warm up traffic to the new domain.

2020-01-27 - Email Geeks

Marketer view

Marketer from Email Geeks says that the need for a warm-up applies to most domain changes, but there is always nuance depending on the specific elements being switched.

2020-01-27 - Email Geeks

Maintaining long-term deliverability

Switching to a new sending domain is a complex but manageable process if approached strategically. It requires meticulous planning, precise technical execution, and a patient, phased warm-up. By prioritizing sender reputation from day one, you can ensure a successful transition that maintains or even improves your email deliverability.

Remember, email deliverability is an ongoing effort, not a one-time setup. Continuous monitoring of your domain's performance, adherence to best practices, and quick responses to any issues will keep your emails reaching the inbox consistently.