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How To Warm Up Email Domain

Published 3/14/2024

Define email domain warming and its importance for email deliverability.

Email domain warming is the process of strategically ramping up the volume of emails sent from a new domain or IP address. This gradual increase helps establish a positive reputation with Internet Service Providers (ISPs) like Gmail, Yahoo, and Outlook. ISPs rely on sender reputation to determine whether to deliver your emails to the inbox or filter them into the spam folder. Warming up your domain demonstrates that you are a responsible sender and improves your chances of reaching your intended recipients, resulting in increased deliverability.

Explain why ISPs are suspicious of new domains/IP addresses.

ISPs are constantly on guard against spammers and malicious actors. New domains and IP addresses lack a sending history, making it difficult for ISPs to gauge their trustworthiness. They see a sudden surge in emails from an unknown source as a potential red flag. This suspicion is a protective measure to safeguard their users from unwanted and potentially harmful content.

Highlight the consequences of not warming up your domain (spam folder, blocked emails).

If you neglect the domain warming process and attempt to send large volumes of emails from a new domain or IP address right away, your emails are very likely to land in the spam folder or, worse, be completely blocked by ISPs. This severely damages your email deliverability, hindering your ability to reach your audience effectively. Inconsistent sending patterns can also trigger suspicion, making it crucial to maintain regular sending habits even after warming up is complete.

Improved inbox placement rates: Email domain warming directly influences how ISPs filter your emails. By establishing a positive sender reputation through a gradual sending process, you significantly increase your chances of having your emails placed directly in the recipient's inbox, rather than being relegated to the dreaded spam folder.

Increased open and click-through rates: When your emails consistently reach the inbox, your open and click-through rates naturally improve. Recipients are more likely to interact with your content when it's presented front and center, as opposed to being hidden away in a spam folder, leading to better engagement and campaign results.

Better overall sender reputation: A warmed-up domain translates to a solid sender reputation. ISPs view you as a trustworthy sender who follows email best practices. This positive reputation can increase your sending limits over time and make it easier to maintain excellent deliverability in the long run.

Protection against sudden spikes in email volume being flagged: Large, unexpected spikes in your sending volume are red flags for ISPs. Warming up your domain trains ISPs to expect a gradual increase in volume, ensuring that sudden changes (for legitimate reasons, like a big campaign) won't trigger spam filters or worse, block your emails entirely.

Step-by-Step Guide to Warming Up Your Email Domain

Warming up your email domain involves gradually increasing your sending volume from a new domain or IP address. Think of it as building a reputation with email service providers (like Gmail, Yahoo, etc.). By starting slow and demonstrating that your emails are wanted and legitimate, you increase your chances of landing in the inbox instead of the spam folder.

Authentication Is Key

Before you even start warming up, make sure you've nailed these authentication protocols:

  • SPF (Sender Policy Framework): An SPF record is a list of authorized servers allowed to send emails on behalf of your domain. It prevents malicious actors from spoofing your domain name to send spam or phishing emails.

  • DKIM (DomainKeys Identified Mail): DKIM adds a digital signature to your email headers. This signature is verified by the receiving server to ensure the email originated from your domain and hasn't been tampered with in transit.

  • DMARC (Domain-based Message Authentication, Reporting & Conformance): DMARC builds upon SPF and DKIM. It tells receiving servers what to do with emails that fail SPF or DKIM checks. You can set policies to monitor, quarantine, or reject emails that aren't properly authenticated, protecting your domain's reputation.

Start Slow and Steady

The golden rule is to begin with a very low volume of emails and then gradually increase the amount sent over time. Here's how this plays out:

  • Focus on Engagement: In the initial stages, it's far more valuable to get high open rates and replies than it is to just send more emails.

  • Sample Warm-up Schedule (for a moderate sending volume):

    • Week 1: Start with 10-20 emails per day to personal contacts or highly engaged subscribers.
    • Week 2: Increase to 50-100 emails per day.
    • Week 3: Gradually increase to 150-250 emails per day.
    • Week 4 and Onward: Continue incrementally increasing volume, monitoring your deliverability metrics (opens, clicks, bounces, spam complaints). If metrics are healthy, you can accelerate.

Important Notes:

  • Consistency is key: Try to send every day during the warm-up to establish a pattern.
  • Quality over quantity: Send valuable, wanted emails to a clean, engaged list.
  • Your Ideal Schedule: The pace will vary depending on your desired sending volume and how well your emails perform.

Focus on Engaged Recipients

  • Higher Deliverability: Engaged subscribers are more likely to open, click, and interact with your emails. This sends positive signals to email service providers, indicating that your emails are wanted and not spam.

  • Reduced Bounce Rates: Engaged users are less likely to have outdated or invalid email addresses, resulting in fewer hard bounces, which can harm your sender reputation.

  • Minimize Spam Complaints: When you send to an engaged list, you'll receive fewer spam complaints, a major red flag that can tank your deliverability.

How to Implement:

  • Segment Your List: Divide your email list based on engagement levels. This could be based on factors like:

  • Open Rate: Past email opens
  • Click-Through Rate: Past clicks on links within emails
  • Recent Activity: Those who interacted with your emails in the last 30-60 days.
  • Prioritize During Warm-Up: Begin your send-outs to your most engaged segments. This builds a strong early reputation with email service providers. Consider adding less engaged subscribers later in the warm-up process in smaller numbers so they don't drag down your metrics.

Content Matters

  • Value is Everything: Focus on providing emails that are relevant, informative, or entertaining to your recipients. This increases the likelihood of opens, clicks, and positive engagement – all crucial signs of a healthy sender.

  • Avoid "Salesy" Language: Aggressive sales pitches, especially in early emails during warm-up, can put recipients off and increase spam complaints. Build trust with valuable content first.

  • Spam Trigger Words: While not an absolute filter, certain words and phrases can increase the chance your emails get flagged. Here are some common offenders:

    • "Free" (especially in all caps)
    • "Money-back guarantee"
    • Too many exclamation points!!!!
    • "Act now" or urgent time-based phrases
    • Words in all caps
    • Claims that seem too good to be true ("Make $1000 a day!")

Proofread! Sloppy emails with typos and grammatical errors signal a lack of professionalism and are more likely to be perceived as spam.

Monitor Your Progress

Open Rates: This indicates the percentage of recipients who open your emails. High open rates show positive engagement – recipients find your content relevant and your subject lines intriguing. Low open rates suggest you need to work on subject lines, targeting, or content.

Bounce Rates: Bounces happen when an email can't be delivered. There are two types:

  • Hard Bounces: Permanent issue (like an invalid email address). High hard bounce rates mean your list needs cleaning.
  • Soft Bounces: Temporary problem (full inbox, server issue). Monitor these, but a few are normal.

Spam Complaints: This is the most serious metric! When someone marks your email as spam, it sends a strong negative signal to email providers. Too many complaints severely damage your reputation and make it tough to reach the inbox.

How Metrics Influence Reputation

Think of your sender reputation like a credit score for emails. These metrics directly contribute:

  • High open rates and low spam complaints: Signal that you're a good sender with engaged recipients. This leads to better inbox placement and higher deliverability rates.

  • Low open rates, high bounce rates, and high spam complaints: Tell email providers that recipients don't want your emails. This can lead to emails being sent straight to spam or even having your account blocked.

Important: Most email marketing platforms provide detailed reports on these metrics. Use those to monitor the health of your campaigns and adjust your warm-up strategy if necessary.

Additional Tips and Best Practices

Dedicated IP Address (for High Volume Senders):

  • Control is Key: If you send a large number of emails, a dedicated IP gives you complete control over your reputation. You're not affected by the behavior of others on a shared IP address.
  • Warm-up Required: Even a dedicated IP requires careful warming to build a good reputation.
  • Not for Everyone: Dedicated IPs can be more expensive and often require more technical expertise. They're usually best for businesses with consistent high-volume email needs.

Warm-up Tools:

  • Automation: These tools automate the process of gradually increasing sending volume while monitoring performance. They save time and potentially catch issues faster.
  • Deliverability Insights: Many warm-up tools provide in-depth analytics, helping you make better adjustments to your sending strategy.
  • Popular options: Check out tools like Warmup Inbox, Mailreach, or GMass 

Consistency is Key (Even After Warm-up)

  • Don't Go Dark: Large gaps in sending can cause deliverability issues to resurface. Aim for consistent emailing patterns.
  • List Maintenance: Keep your email list clean by regularly removing inactive subscribers. This protects your open and click rates over the long term.
  • Monitor Metrics: Always track your core metrics, even after warm-up. They provide an early warning sign of potential deliverability problems.

The Rewards of a Warmed-Up Email Domain

  • Inbox Success: A warmed-up domain improves your deliverability rates, meaning more emails actually reach the recipient's inbox instead of getting lost in spam.
  • Stronger Reputation: You build a positive reputation with email providers, making it less likely for your messages to be flagged mistakenly in the future.
  • Better Engagement: Increased opens, clicks, and conversions since your emails are reaching an audience that wants to hear from you.

Take Action and Reap the Benefits!

Don't let cold emails ruin your marketing efforts. Start warming up your email domain today by following the strategies we've discussed:

  • Set up authentication (SPF, DKIM, DMARC)
  • Start with a small sending volume and gradually increase
  • Focus on your most engaged subscribers
  • Provide valuable, non-spammy content
  • Monitor your metrics and adjust your strategy as needed