Email Domain Warming: Best Practice Tips and Tricks

In February 2024, Google and Yahoo introduced new email delivery standards that you need to know about. These standards emphasize sender authentication and recipient preferences to keep spoofed and unwanted mail out of our inboxes.

Successful email deliverability is based on two things: IP Address and domain sender reputation. Today, we’ll focus on domain sender reputations because part of Google and Yahoo’s changes includes requiring a custom email sender domain, which is the part that comes after the @ symbol. 

Changing your sender domain will require a “warming up” period to build credibility with the mailbox providers (such as Google and Yahoo) that will receive your mail. When sending bulk email, mailbox providers need to confirm that your new domain is a reputable sender and not a mass-blast spammer.

In order to establish a good reputation, domain warming requires some time and patience. The warm-up process is done by breaking your list down into small segments and emailing one segment at a time over a consistent period (more on this below).

Here are a few tips on warming up your sender domain:

Create a timeline and be patient.

Depending on your list size, this process could take up to a few weeks as you will need to slowly ramp up the amount of emails you are sending week over week.

Here are a few examples:

Let’s say you have a total list of 10,000 leads. For best practice, it is recommended that you send 500 emails per day for 5 days. During this 5-day period, monitor your performance day over day to identify if there is an increase in your delivery rate, open rate, and click-through rate. If after 5 days those numbers still seem low, continue sending at that pace. If the engagement rates are where you want them to be, then you could increase to 1,000 emails over the next 5 days. After 10 days, if you see positive improvements, you can increase to your remaining 2,500 leads.

Here’s a breakdown:

DAYS	EMAILS SENT
1-5	500/day
6-10	1,000/day
11	2,500/day

If your list size is over 50,000 leads, begin with the same pace as above. However, once you reach day 11 you can go from 2,500 to 5,000 emails sent per day for a few days, then ramp to 10,000 per day. Continuously monitor performance throughout this process! Don’t email all of your leads at once (more information to come on that later).

Here’s a breakdown:

DAYS	EMAILS SENT
1-5	500/day
6-10	1,000/day
11-15	2,500/day
16-20	5,000/day
21+	10,000/day

If your list size is less than 10,000 leads, you can be more conservative with how many emails you send per day. For example, if your list size is 1,000 leads you could send only 200 emails per day until your list size grows.

Start with your best performing email message and most engaged audience.

Email deliverability is highly dependent on engagement. You’ll want to make sure the email you send has a historically high open rate and click-through rate (this is not the time to try something new!).

Deliverability is about more than just getting the email to land in a prospect’s inbox. It’s about ensuring those prospects engage with the content you are sending. When people open your message and click the links inside, that interaction tells the mail server that you are a reputable sender. Besides opens and clicks, the best engagement signal to an email server is a reply to your email. Asking questions that elicit a response is one of the best ways to improve deliverability. Keep in mind that the “reply to” email address needs to be real and monitored. 

By starting the warmup process with your most engaged audience, there is a far higher likelihood that the people you send it to will open your email and click on links within it. You want to avoid sending emails to prospects that are likely to immediately delete or unsubscribe from your emails.

Don’t send bulk emails intermittently. 

Keep your email send threshold consistent day by day as you ramp. Continue that frequency for a few weeks after you’ve reached your highest volume. Try to avoid spikes in volume, as this will appear as a red flag to Google. 

If you max out your list of 10,000 leads and don’t want to email all 10,000 leads daily, you can scale back the number of emails sent in a single day and use a staggered approach instead. You do not need to send 10,000 emails per day, every day, but you will need to create a consistent schedule to avoid massive gaps in sending. It’s okay to have a day or two in between sends, but do not wait two weeks to send your next email and then blast 10,000 recipients at once, as Google will not be happy.

For example:

• Do: send 1,000 emails per day for 10 days to create consistency for Google and Yahoo
• Don’t: send 10,000 emails on a single day and wait 10 days before sending another message

Monitor performance and scale back if necessary

Constant monitoring is essential to a successful domain warming. If you see low delivery rates, reduce the number of emails you are sending out. Don’t rush this process.

Here are a couple of extra tips for success:

• Before you begin this process, clean your list. Remove bad email addresses like “na@na.com” or misspelled emails (a common typo is gnail.com instead of gmail.com).
• Create a schedule of top-performing emails. You don’t want to run out of emails or send the same prospects the same email over and over again. Create a send schedule for when you’ve maxed out your sendable list that will help you maintain consistency in your sending activity.
• Keep transactional emails, like confirmations and receipts, running. These are necessary for everyday business and they usually have high engagement rates. There won’t be as many emails sent in a day as a promotional email broadcast, and can help create a variety of email send types. This is a green flag for Google.
• Utilize free monitoring tools like Google Postmaster Tools. This tool helps you analyze your email performance, helps Gmail route your messages to the right place, and can provide information on Gmail delivery errors, spam reports, feedback loops, and more.

Overall, the goal of the warm-up process is to have a steady, consistent volume of emails, and email domain warming is critical to ensure you have a successful email marketing strategy. By following these best practices, you can effectively warm up your email domain, establish a positive email sender reputation, and set yourself up for successful email campaigns that engage your audience and drive results. Kartra is here to help you through this transition – for ease of scheduling your broadcasts in advance, use the Kartra “Send/Schedule” step in our email broadcast builder, the best tool to help you get more reads, more clicks and more customers!