How to warm up your domain and IP address for your email marketing campaign

Kate L. | October 17, 2023
11 mins

It’s no secret that email marketing is an important instrument that allows businesses to effectively connect with their potential and existing customers. And it’s in a business's best interest that their email marketing campaigns reach as many people as possible when they create email outreach. If you want to send your marketing campaigns via a new domain or IP address, and you want to ensure that your subscribers receive your emails, domain and IP warm-up will come in handy.

If you’re interested in creating your first email marketing campaign, we have a detailed guide on that topic: 
Email marketing 101 →

What is a domain and IP warm-up?

Domain and IP warm-up is the process of steadily increasing your email sending volume over a few weeks creating a favorable email reputation for your new domain until it's fully "warmed up" and ready for the volume you need for your marketing campaign without being flagged by spam filters. 

It's crucial to start slowly and gradually increase the number of emails you send. A recommended schedule might be to begin with 10 emails per day in the first week and then progressively increase the volume over the period of 4-6 weeks, maintaining consistency in both email quantity and the sending schedule.

Deviating from such a schedule can result in being flagged by spam filters, so you may adapt it as needed while keeping the gradual approach in mind.

Why domain and IP warm-up are important?

Every day about 14.5 billion emails are marked as spam worldwide, accounting for nearly half of all emails sent daily. Spam is often filtered before the recipient even sees it. As a business sending big mail outs to your subscribers, the last thing you want is to be classified as spam by the email service providers.

At the same time, accomplishing this task has become increasingly challenging over time due to the fact that major email providers have significantly enhanced their spam detection capabilities, making their spam filters stricter. In addition, if emails are sent from a new (or ‘cold’) sending domain/IP address, there is a higher risk that messages will be rejected or filtered into spam folders, and users will never see them. This happens because IPSs (Internet Service Providers) and Email Service Providers (like Yahoo, Gmail, Outlook, etc) tend to view new domains and IP addresses with suspicion because they have no sending reputation yet. As your domain and/or IP address gain historical data and email activity record, email service providers will gradually allow you to send more emails without getting blocked.

When is domain and IP warm-up necessary?

In cases when you just registered a domain name and acquired a new dedicated IP address for your email service, it’s clear that you will need to warm up both of them to ensure good email deliverability since they’re both considered ‘cold’ at this point. Let’s look at other possible scenarios.

If you're assigned a new IP address (e.g. when you switch email hosting providers or you just have a new dedicated IP assigned to your email service), but your sending domain remains the same – you still might encounter mail deliverability issues during your email outreach.

It’s worth noting that warm-ups are only required for dedicated IPs. If you’re using a service like Namecheap Private Email or Shared Hosting - that use shared IP addresses - the IP addresses are already warmed-up and you will only need to make sure that your domain is also warmed-up.

Or the opposite can be true —  you might be pairing a newly registered domain with an already-warm IP address. Be aware that, in these cases, email service providers treat new domains with even more caution than new IP addresses.

How to warm-up your domain (and IP address) 

There are two types of warm-up processes: manual and automated. At Namecheap, we don’t provide an automated process, so we’ll only look at the manual option here.

Set up your email account

First things first, you will need to purchase an email service (like Namecheap Private Email or Shared Hosting) and create a mailbox. Then you will need to make sure that DNS for your email domain is set up properly. Besides MX records, that are necessary for the proper function of email services, you will need to set up SPF and DKIM records (you can also set up a DMARC record for maximum efficiency). They’re email authentication mechanisms designed to help prevent email spoofing and phishing attacks, and are essential for email security. These DNS records are used by mail servers to verify the authenticity of incoming email messages. In 2023, many email service providers will simply reject emails sent from domains that don’t have these aren’t set up properly, so it’s worth double checking that everything is in order before you begin the process.

If SPF/DKIM/DMARC records are missing, it may be one of the reasons that:

  • Outgoing emails being delivered to Spam/Junk folders;
  • Outgoing emails not being delivered to the recipient server with a bounce-back email with ‘High probability of spam’ reason;
  • Criminals may try to spoof emails on behalf of your domain. 

NOTE: Email spoofing is ​​a forging of an email address to make it seem like the message has been sent from you to trick people into opening it.

Personalize your mailbox

It’s important that your emails look authentic to recipients, that’s why you should personalize your email address by adding your name, as well as a signature. For best results, include the following details in your email signature:

  • Name
  • Job title
  • Company name
  • Address
  • Phone number
  • Email address
  • Website

If you want to use a signature that includes your photo, company logo, etc, rather than a plain-text signature, feel free to include that as well. However, take into account that if the footer’s HTML is messy and is larger than the body of your message, it may actually trigger anti-spam filters, resulting in your emails being rejected.

TIP: When setting up your email account, you may want to ensure that your email address is associated with a real website to add to its credibility. The specific website you link to your account is not critical at this stage though, and can be modified later if needed.

Check how old your domain is

As we mentioned earlier, newly registered domains are often marked as suspicious by spam filters because they assess the age of a domain. If it is less than 30 days, the domain is automatically flagged. This is done specifically to ensure that users don’t receive spam or malicious emails from senders who try to get around restrictions by frequently switching through multiple domains. 

It’s known that large numbers of emails from unknown IP addresses usually originate from spammers. They often use the same pattern: the purchase of a new domain or email plan followed by mass spam sending before the new address is blocked by the email service provider. 

Consequently, any emails sent from domains like this are also treated as suspicious. It's advisable, then, to wait thirty days before beginning your warmup process, to avoid facing deliverability issues or possible rejections of your emails.

NOTE: You can check how old your domain name is using Namecheap Whois Lookup  

Create high-quality content

Writing a relevant and quality email copy is a must if you want to create high engagement with customers. If your email content appears scammy, or lacks relevance, users may choose not to click any promotional links, leading to a diminished chance of future email openings. There are several strategies to enhance your content:

  • Readability. Vary the length of your email content to match your email's purpose. For instance, sales emails or lead generation messages should be brief, as readers don’t want to look through too much text, especially if it's promotion of products or discounts. 
    At the same time, newsletters or other marketing emails may be longer. In addition, ensure that your email content is easily readable by creating short, clear sentences, organizing content into small paragraphs, and using an easy-to-read font that users can swiftly scan.
  • Avoiding spam patterns. Write in a human-like manner, avoiding generic placeholder text like "lorem ipsum”, spam words and patterns (you can check this guide for examples: Why emails go to spam and what to do  ).

    It’s also advisable to avoid formatting, such as all capital letters (e.g . OPEN), letters with spaces between them (e.g. O P E N), and excessive punctuation (e.g., O.P.E.N). The symbols that will likely get emails blocked are: !!!, $$$, and 100% (e.g. 100% free*). In addition, always include meaningful subjects.
  • Personalization. Create copy for your email content in a way that's likely to resonate with the recipient. For example, you can use their name or personalized suggestions. This enhances reader interest and encourages them to check out the entire message.
  • Mobile optimization. According to Fluent, 75% of consumers use their smartphones most often to check emails. That's why you need to ensure your emails are good to go across all devices, meaning the layout, font size, and images are responsive and accessible on smaller screens.

Start sending emails manually

Once you've set up your email account, DNS records, and begun creating content for your campaigns, you can start gradually sending emails from your fresh mailbox. Here are a few points to pay attention to:

  • Recipients
    Since the quality of email addresses is crucial in this process, it's important to send emails to addresses you are familiar with. These can be your own email addresses or those of the recipients who’ll readily respond to them (e.g. your family, friends, colleagues, etc). It's advisable to send emails to addresses of different email providers such as AOL, Yahoo, Yandex, Gmail, Outlook, etc.
  • Reply rate
    Once you're done with sending out emails, make sure you get the recipients to reply to the emails you send as this helps the providers to learn that your emails are legitimate and you’re not sending spam (this is especially important with Gmail). When replying to the emails you sent, it’s important to maintain a natural approach, and reply as you normally would during any other correspondence so that it sounds neutral.

    In order to accomplish this, make sure each email was delivered successfully to the recipient’s Inbox. If the email was marked as spam/junk by the email provider, ask the recipient to mark it as not spam and move it to the Inbox folder. 
  • Volumes
    As we mentioned earlier, it’s important to start slow and gradually increase the number of emails you send during your warm-up process. Begin by sending a maximum of 10 emails per day and gradually increase the volume. Consistency in both the number of emails and the sending schedule is important. Sending excessive amounts of emails too quickly may result in being flagged by anti-spam filters. Here is a possible schedule you can follow:

Week 1: 10 emails
Week 2: 30 emails
Week 3: 80 emails
Week 4: 100 emails
Week 5: 150 emails
Week 6: 200 emails

Please take into account that this is just an approximate scheme and you may not follow it strictly.

  • Know your sending limits
    Every email service provider establishes how many emails can be sent by users daily, so it may be handy to know the sending limits of your email service provider so that your account is not restricted, and your warm-up process is consequently successful. Namecheap also has specific hourly and daily limits on the number of messages users can send. You can check them in this guide before you start your warm-up process: Do you have any restrictions on sending out emails?

What else influences your email reputation score?

Now you know how to warm up your email, let’s take a look at some other factors that can influence your email reputation score during your email outreach:

  • The number of emails sent out;
  • The percentage of your emails marked as spam by recipients;
  • How many emails were marked as ‘ham’ (this is where the recipient actively moves it out of their spam folder, into their main inbox);
  • The number of email bounces; 
  • Engagement level (e.g. how many recipients, email open rates, click on links, reply to it, forward it to someone else);
  • The number of users who hit ‘Unsubscribe’ in your email if this option is present there;
  • How old your domain name is.

It’s important to note that every email service provider defines what factors they rely on when calculating a sender’s reputation. So your reputation score may differ slightly with every provider. But you can check your general reputation score using one of these external resources:

As an aside, it’s worth noting that it's much easier to establish a good new email sending reputation than to fix it if it goes bad, so warming up is likely to start your domain and IP address on the right footing for the longevity they need.the bad one. That’s why the initial warm-up process is crucial for your domain or IP address.

What are possible risks during a warm-up process?

Be ready when you start warming up your domain (or IP address) for blockings, delays in delivery, and bounce-backs on the side of the email providers. Stay flexible. What should you do when this happens?

On the sender’s side: proceed with sending out emails following the recommendations in this guide. At the same time, refrain from increasing email volumes for some period of time On the recipient’s side: make sure that all the emails delivered to the Spam folder are moved to Inbox and replied to. Alternatively, recipients can add the sender to the acceptlist on the side of their email provider so that future emails are delivered as normal.

Over the time of the warm-up process, though, these issues should disappear, and your  should be delivered as you'd expect to its recipients. That’s when you can start freely sending messages to the subscribers for your email marketing campaign.


Picture of Kate L.

Kate L.

Private Email Product Coordinator

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