How to Warm Up Your Email Domain: 5 Simple Steps

Email is the leading revenue-generating channel, making it an indispensable channel for outbound sales teams to connect with leads and prospects. However, without proper preparation, i.e. email warm up, your emails might not even reach the recipient’s inbox. This is where warming up your email domain comes into play. In this blog, we’ll explore what email domain warming is, why it’s essential, and how to implement it effectively to ensure long-term success in your email outreach campaigns.

Table of contents

1. What is email domain warm-up?
2. Why warming up your email domain matters
3. How to warm up your email domain correctly and responsibly
4. Do’s and don’ts of email domain warm-up
5. When to warm up new domains
6. How Allegrow can help

What is email domain warm-up?

Email domain warm-up refers to the gradual process of increasing the volume of emails sent from a new or dormant domain. This process helps establish a positive sender reputation with email service providers (ESPs), such as Gmail, Outlook, and Yahoo. Why does this matter?

ESPs use algorithms to assess the sender reputation of domains. This reputation determines whether your emails land in the inbox, spam folder, or are blocked entirely. A strong sender reputation ensures higher email deliverability and inbox placement rates, whereas a poor reputation can result in emails being marked as spam or rejected outright

Additionally, warming up your domain builds trust with ESPs by demonstrating consistent and responsible email-sending practices.

Let's dive a little deeper into why warm up is so important.

Why warming up your email domain matters

Warming up your email domain is a key step in ensuring the long-term success of your email outreach, especially in outbound sales. As highlighted above, the process is about building a strong initial sender reputation. This reputation, monitored and evaluated by ESPs, directly influences whether your emails land in the recipient's inbox or are flagged as spam. Without proper warm-up, your campaigns risk low deliverability and wasted efforts on the sales side, i.e. burning through contact lists

A strong sender reputation serves as the foundation for improved email deliverability. ESPs use sophisticated algorithms to evaluate each domain’s email-sending behavior. These systems look for patterns, such as consistent sending volumes and high engagement rates, to determine if a sender is trustworthy. A sudden spike in email volume from a new or inactive domain can trigger red flags, causing these providers to view your emails as potentially harmful or spammy. Gradually warming up your email domain avoids this scenario by establishing trust with ESPs over time.

This trust-building process also benefits your business by increasing the likelihood that your emails will land in recipients' primary inboxes. When emails consistently land in inboxes, they are more likely to be opened, read, and acted upon, leading to better engagement metrics such as higher response and click-through rates. These metrics feed back into the reputation cycle, further strengthening your domain's standing with ESPs.

In addition to boosting deliverability, email domain warming also helps safeguard your brand credibility. A poor sender reputation can damage your ability to communicate with customers and prospects at key moments in the sales cycle. Warming up your domain ensures that your emails are perceived as legitimate and valuable, reflecting positively on your brand.

Finally, the process of domain warm-up directly impacts the return on investment (ROI) of your email campaigns. With better inbox placement, your sales team can reach more prospects, generate more leads, and ultimately close more deals. Investing time in proper domain warming is an essential step to maximize the effectiveness of your outbound sales efforts and protect your domain from being flagged or blacklisted in the future.

In very simple terms, email warming serves to: 

Improve inbox placement rates: A gradual warm-up process helps emails reach recipients’ primary inboxes rather than the spam folder.

Reduce spam flags: Consistent and responsible sending practices minimize the risk of being flagged as spam.

Better engagement metrics: Higher response and click-through rates enhance the success of your campaigns.

So, now we’ve covered why it’s important, it’s time to look at how it can be done.

How to warm up your email domain correctly and responsibly

To build up a strong sender reputation, and reduce the likelihood of your emails hitting the spam folder, you should follow the following steps to correctly warm up your domain:

1. Start small

Begin by sending a low volume of emails each day–we suggest 20-50 emails. Starting with small volumes allows ESPs to analyze your sending behavior without raising suspicion. It demonstrates that your domain is being used responsibly and helps establish an initial pattern of trust.

Remember: Once you're domain is warmed up, it's important to be aware of the daily sending limits for each email service provider, and not to surpass these.

2. Gradual increase

Incrementally increase your daily email volume by 10-15% per week. This slow and steady growth mimics natural, organic sending behavior and prevents sudden spikes, which can be seen as suspicious by ESPs. Consistency in volume increases is key to gradually proving that your domain can handle larger outreach without compromising reputation.

3. Send to engaged recipients

Target recipients who are most likely to interact with your emails, such as internal employees, loyal customers, or other known contacts. Starting with engaged recipients increases the chances of high response and click-through rates, which ESPs receive as positive signals. This strategy helps establish your domain as a legitimate and trustworthy sender before expanding to cold prospects.

Pro tip: Before sending out your emails, always run a risk analysis on your contact lists. This ensures you're not targeting any frequent spam reporters, bouncers, or contacts who aren't likely to engage with your emails.

4. Monitor metrics

Track key metrics like response and click-through rates, bounce rates, and spam complaints closely throughout the warm-up process. High bounce rates or a spike in complaints can harm your sender reputation, so adjusting your strategy based on performance indicators is essential. Regular monitoring also allows you to detect and resolve issues, such as invalid email addresses, early in the process.

5. Authenticate your domain

Ensure you have SPF, DKIM, and DMARC records correctly configured for your domain. These authentication protocols validate your domain’s legitimacy and help ESPs verify that your emails are not being spoofed. Proper authentication significantly reduces the likelihood of emails being flagged as spam, enhancing deliverability and strengthening your sender reputation.

Pro Tips:

• Organize your contact lists into segments and send personalized messages to boost recipient engagement.
• Avoid using suspicious language, excessive capitalization, punctuation, or attachments and links during the first interactions until engagement has been established.
• Use sending platforms that integrate with tools like Allegrow to automate and optimize the warm-up process.

How long does email warm-up take? 

The warm-up duration depends on a few factors such as:

• Domain age: New domains may take anywhere from 4–8 weeks of warming up
• Target volumes: Higher sending goals require a longer warm-up phase
• Recipient engagement: Positive responses can accelerate the process

In brief, this means is that warming up a new domain that will be used to send 100 emails a day will likely take less time, than warming up a domain that will be used to send 1000+ emails a day.

Do’s and don’ts of email domain warm-up

As important as it is to follow the appropriate steps to warm up your email domain, there are some best practices to follow, and some steps you definitely shouldn’t do, to increase the success of your warm-up activities.

Do’s:

• Carry out risk analysis on contact lists: It’s not enough to ensure email addresses are valid. You need to ensure that all contacts who are likely to mark you as spam, bounce (soft or hard), or not engage with your content are removed from lists, ahead of sending - ideally use a Safety Net tool for this.
• Focus on quality: Prioritize sending meaningful and engaging emails over mass distribution during the warm-up period.
• Maintain consistent sending patterns: Regular, predictable activity builds trust with ESPs.

Don’ts:

• Avoid purchased or scraped email lists: These lists often contain invalid or unengaged addresses, leading to spam complaints and bounces.
• Don’t send large volumes prematurely: Scaling up too quickly can damage your sender reputation.
• Avoid neglecting authentication: Without proper authentication protocols like SPF and DKIM, your emails are more likely to be flagged as spam.

When to warm up new domains

There are specific scenarios where warming up a new domain or subdomain is crucial:

Protecting your core domain: If multiple teams in your organization are sending email outreach, using subdomains for campaigns prevents overloading your primary domain.

Recovering from account suspensions: If your account has been flagged or suspended, warming up a new domain can help restore deliverability.

Launching a new account: Any new account sending outbound emails should begin with a warm-up process to establish trust with ESPs, especially when you’re emailing over 1,000 prospects a month.

Scaling up outreach: If you’re expecting to increase your email sending volume over the next 12 months

How to use Allegrow to warm up your domain

Establishing a strong sender reputation is crucial when warming up a new subdomain or alternative domain. Since the selected domain will have minimal history with email providers, warming it within the Allegrow network is essential. 

This process involves creating positive engagement to show that your domain receives favorable responses and is associated with a trustworthy sender.

The Allegrow network makes reputation-building a breeze through various activities, including:

• Reply Threads: Simulated B2B conversations are created by replying to test emails, mimicking authentic interactions.
• Spam Recovery: Emails landing in spam folders are automatically marked as "not spam" to boost sender reputation.
• Priority Marking: A portion of simulated email traffic is flagged as important to enhance engagement metrics.

These activities are carefully managed and automatically throttled within Allegrow. Additionally, you’ll receive a throttling formula and detailed guidance on gradually increasing activity in your sending system for optimal results.

Aside from just warming up your domains, features available also include:

• Real-time insights: The platform provides detailed analytics on deliverability and sender reputation.
• Contact risk analysis: Identify and remove harmful contacts from campaigns and cadences proactively using a tool like Safety Net.
• Content risk analysis: A/B test email variables and choose to send only the versions with the lowest spam rates and highest reputation score

Summary: How to warm up your email domain

Email domain warm-up is a foundational step for successful outbound sales campaigns. By gradually increasing your email volume and adhering to best practices, you can build a strong sender reputation, enhance deliverability, and achieve better engagement rates. Here's a quick recap:

1. Send a low amount of emails each day
2. Gradually increase the number each week by 10-15%
3. Prioritize sending emails to your most engaged users
4. Monitor engagement metrics - optimize your sending accordingly
5. Ensure correct domain authentication setup

Ready to get started, or even optimize your email domain warm-up? Try Allegrow’s tools and start building a stronger foundation for your email outreach success today.

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