Email Warm-Up Checklist for New Domains in 2025

Why email warm-up matters for new domains

Before we discuss why warmup matters for new domains when it comes to email marketing, we need to answer one frequently asked question.

Q: Why do you need a new domain for outreach in the first place?

A: Using your primary business domain (the one your website and customer communications are already built on) for cold outreach is risky. If your outreach campaigns trigger spam complaints, high bounce rates, or poor engagement, your domain reputation can take a hit. Inbox providers could flag you and even blacklist your domain. This can then affect all emails sent from your company—including support emails, transactional emails, client communications, and even order confirmations. 

🔖 Related Reading: Importance of Email Warmup before Cold Outreach

This is why smart brands and marketers create a new domain or subdomain dedicated solely to outreach. Then, they warm it up before sending any real campaigns. Done right, this protects your core domain while improving inbox placement, and increasing the chances of outreach success. 

Here are other reasons why email warm-up is beneficial for new domains:

It helps you avoid the spam folder

When inbox providers identify that an email has been sent from a new domain, they treat it with caution. After all, there’s no sending history. There’s no credibility or authority—yet. So when a new domain sends bulk emails right away, inbox service providers may flag your domain or your email address as spammy and suspicious. When this happens, the next emails you will send have a higher chance of landing in spam or getting blocked.

Warming up your domain tells ESPs that you’re a legitimate sender. It introduces your domain gradually, using safe sending patterns and positive engagement signals like opens and replies. This builds trust over time—and trust is the key to staying out of spam.

🔖 Related Reading: The Warmy Research Team recently conducted an experiment to examine how different warm-up strategies affect the deliverability of emails from newly created domains. You can access the full report here: The Science and Process of Warming Up Newly Created Email Domains.

Building a positive sender reputation

Sender reputation is another factor that affects overall deliverability. So for new domains, this can be a challenge as they have no reputation yet. In the world of emails and inboxes, sender reputation is like a credit score. It is built over time and it’s based on how recipients interact with your emails and your domain. 

A new domain starts with a neutral reputation. Warming it up helps shape a reputation positively from day one. Over time, inbox providers start recognizing your domain as safe and trustworthy. This will also help you improve deliverability in the long run. Skipping this step and blasting emails to large lists right away is one of the fastest ways to burn your domain—and your chance to reach inboxes consistently.

Ensuring long-term email deliverability

Email warmup isn’t just a one-time big-time project. It’s the foundation for long-term deliverability. A well-warmed domain continues to perform better, even as you scale up your campaigns. When done correctly, warm-up helps you:

• Get more emails into the primary inbox, not the spam or promotions tab
• Reduce bounce rates by sending to cleaner, more engaged contacts
• Increase open and reply rates, which further strengthens your reputation
• Avoid blacklists and maintain compliance with major email providers

Key takeaway: A good email warm-up is about building up your domain’s reputation slowly, steadily and cautiously. It’s how you earn the trust of inbox providers like Gmail, Outlook and Yahoo and get your emails delivered, opened and clicked. Remember, no amount of great content and design can save you from bad deliverability if you haven’t warmed up.

Pre-warm-up technical setup checklist

Let’s get one thing straight: email deliverability success takes a lot of factors into consideration. Before you start building out the actual content, you need to make sure that your domain is technically prepared to “warm up.” You may have the greatest email ever in your pipeline, and if it doesn’t make it to the inbox, it’s useless.

Even if you do go ahead with a warm-up process, it will not generate beneficial results if there are issues with the technical side. You don’t want to simply do a warm-up process for the sake of it. So before you start sending emails, take a step back to set yourself up for success.

Think of it as laying a solid foundation before building a house. This section will cover the necessary technical steps you should take to ensure that your emails have the best chance of reaching the inbox.

1. Register a clean domain

A clean domain means one that has no previous email reputation issues or spam complaints associated with it. This is important because email providers monitor domain age and previous reputation. Starting fresh allows you to build your reputation from the ground up without inheriting negative baggage.

Tip: Avoid using your primary business domain for cold outreach to prevent risking your current reputation. A subdomain dedicated to outreach is safer and more effective.

2. Set up essential DNS records (SPF, DKIM, DMARC)

When you register your domain, it’s a must to configure your DNS records. Think of these records as the instructions that email servers follow to verify that your messages are from a verified source.

• SPF (Sender Policy Framework): This lets email senders know which IP addresses are allowed to send emails on behalf of your domain.
  
• DKIM (DomainKeys Identified Mail): This includes a cryptographic signature in your emails to show that the content of the email wasn’t altered along the way.
  
• DMARC (Domain-based Message Authentication, Reporting & Conformance): This tells email servers what to do with emails that do not pass SPF or DKIM and lets you track how well your domain is doing with your mail.
  

🔖 Related Reading: SPF, DKIM, and DMARC: Boosting Email Security and Deliverability

3. Create a professional mailbox structure

• Use a professional naming convention for your mailboxes. Try to avoid using something generic or sketchy sounding like “sales123@” or “marketing@” as these can raise red flags with email providers.
• Use names that look like real people are sending the emails, such as “jane.doe@” or “john.smith@.” This is better for your email’s credibility and reduces the chances of getting marked as spam. 
• Make sure you have an inbox just for outreach.This helps to separate cold outreach from other communication and gives you better control over your email health.

The must-have email warmup checklist for new domains

Now that your domain is set up and ready for action, it’s time to start the warm-up process. This checklist will guide you through the crucial steps needed to gradually build a positive reputation with email service providers (ESPs). By following these steps, you’ll ensure that your emails make it to the inbox and avoid spam filters.

Step 1: Set up inbox monitoring

Monitoring your domain’s inbox health is key to understanding how email providers view your messages. Setting up inbox monitoring tools helps you track your domain’s reputation and see how your emails are performing across different providers. This allows you to make adjustments early on if there are any signs of deliverability issues.

What to do:

• Use Google Postmaster Tools: Sign up and link your domain to Postmaster Tools to track your reputation with Gmail.
  
• Set up Microsoft SNDS (Smart Network Data Services): This tool lets you track your domain’s performance with Outlook and other Microsoft email services.
  
• Monitor with Warmy.io: Warmy offers a free deliverability test that gives senders an idea of their inbox placement rate across various ISPs.
  

2. Start with low volume sending

We get it—you’re excited. You’re brimming with lots of ideas for email marketing campaigns. However, “slow and steady wins the race” is also very much applicable when it comes to email warm-up and email outreach.

Starting with a low volume of emails and gradually increasing helps inbox providers recognize your domain as a legitimate sender. If you send too many emails too soon, you risk triggering spam filters .

Q: What are spam filters?

A: Spam filters are tools used by email service providers to detect and block unwanted or harmful emails, such as those containing spam, phishing attempts, or malware. They analyze various factors like sender reputation, email content, and engagement to decide whether an email should be delivered to the inbox or marked as spam.

What to do:

• Send 5-10 emails per day in the first week: These emails should be sent to engaged recipients, such as colleagues or test accounts.
  Avoid sending to large lists immediately: Focus on high-quality, warm contacts rather than sending to bulk or unverified lists.

3. Prioritize engagement

Email providers care about engagement. If recipients are opening, replying, and interacting with your emails, your domain is seen as valuable and trustworthy. On the other hand, if your emails are ignored or marked as spam, your sender reputation can suffer. Ensuring high engagement early in the warm-up process is essential to building long-term deliverability.

What to do:

• Send personalized emails: Make your initial emails look personal and not too salesy. Personalized content tends to get higher engagement.
• Request replies: Encourage your recipients to respond to your emails. This shows ESPs that your emails are worth engaging with.
• Avoid large marketing messages: The first emails should not be newsletters or promotions. Focus on simple, conversational emails.

4. Ramp up sending volume gradually

Once you’ve warmed up your domain with low-volume sends, it’s crucial to increase your sending gradually if you ever hope to get to a point where you can send bulk campaigns. Rapid volume increases can overwhelm ESPs and result in your domain being flagged. A gradual ramp-up shows that you’re a legitimate sender, ensuring better inbox placement and reducing the likelihood of being blacklisted.

What to do:

• Increase volume by 10-20 emails per day each week: Gradually ramp up your email sends as you progress through your warm-up. Keep the list small but engaged.
• Monitor your bounce rates: If your bounce rate starts to increase, slow down your volume increase and investigate the cause.
• Gradually expand your list: Begin including people outside of your internal network, but ensure they’re still engaged (e.g., warm leads, subscribers).
  

🔖 Related Reading: Maximizing Email Deliverability: Grouped vs. Randomized Sending is another experiment by the Warmy Research Team where they tested two methods to analyze which approach leads to higher inbox placement and better engagement. 

Take your warmup to the next level: Use a warmup tool to automate the process

While effective and very much recommended, manually warming up a domain can be time-consuming and error-prone. However, a dedicated email warm-up tool, like Warmy.io, automates the process—making it easier to do all of these things at the same time: increase sending volume, track engagement, and ensure that your domain is protected from potential deliverability issues. It also saves you from making manual mistakes that could hurt your reputation.

Here’s a quick list of how Warmy can help you achieve all of the things in the email warmup checklist:

Free SPF and DMARC Record Generators

As mentioned above, properly setting up your SPF and DMARC records is essential for email authentication which helps to establish your domain’s legitimacy. These records ensure that your emails aren’t flagged as suspicious by email service providers (ESPs).

Warmy has a free SPF Record Generator and a free DMARC Record Generator to help you quickly set up and verify these essential records for your domain. They ensure your emails pass the necessary checks, preventing deliverability issues right from the start.