Warming up a sending domain is essential for ensuring high deliverability rates and maintaining a good sender reputation. This guide will walk you through the best practices for warming up a brand new domain and when switching between email service providers (ESPs).

​
What is Domain Warming?

Warming up a sending domain involves gradually increasing the volume of emails sent from a new domain to build a positive sender reputation with Internet Service Providers (ISPs). This is crucial when starting with a new domain or even changing ESPs to avoid being flagged as spam.

​
Preparing your domain

If you’re planning to use a brand new domain:
  • Set up your authentication records (DMARC, SPF, and DKIM).
  • Verify your domain in your email service provider.
  • Ensure your domain is clean and hasn’t been previously blacklisted.
If you’re using the same domain, but switching ESPs:
  • Verify DKIM, SPF, and DMARC records are updated to reflect the new ESP.
  • Re-import and map all contact permissions accurately to the new system.

​
The Warm Up Process

Warming up your sending domain will take at least 3 weeks. Here’s the process we recommend: Week 1:
  • Send emails to your most engaged users (open rates > 30%).
  • Limit volume to 50-100 emails per day.
Week 2:
  • Gradually increase the volume by 100% daily, targeting engaged users.
  • Monitor bounce rates and engagement closely.
Week 3 and Beyond:
  • Continue to double the daily sending volume each week.
  • Begin including less engaged users in small batches.
  • Adjust the pace based on ISP feedback and engagement metrics.

​
Best Practices

Monitor Performance:
  • Use tools to track open rates, click-through rates, and bounces.
  • Watch for any signs of being flagged as spam and adjust accordingly.
  • Use the available Postmaster tools (i.e., Google and Yahoo) to monitor your domain’s health.
Engage with Contacts:
  • Send personalized and relevant content.
  • Promptly handle unsubscribe requests to maintain a clean list.
Maintain List Hygiene:
  • Regularly update and clean your email list.
  • Remove inactive contacts to improve engagement metrics.
Compliance:
  • Ensure all contacts have explicitly opted-in to receive emails.
  • Adhere to CAN-SPAM Act regulations and other relevant laws.

​
Troubleshooting

High Bounce Rates:
  • Review and improve email content and relevance.
  • Verify email addresses and use double opt-in methods.
Low Engagement:
  • Segment your audience further for more targeted and personalized campaigns.
  • Improve subject lines and email content to boost interest.
By following these steps and best practices, you can effectively warm up your sending domain, ensuring high deliverability and a strong sender reputation.