The importance of warming up your domain & how to determine success

This article explains the importance of warming up your email domain and provides guidance on how to determine the success of the warming-up process.

Why is warming up your domain important?

When you add your domain to send emails via the Mobile Marketing Cloud, warming up your domain is crucial to avoid your emails ending up in the SPAM folder. This can happen if you send a large batch of emails (e.g., >3000) all at once from a known domain using a new IP address. Email providers may flag this as SPAM due to the sudden spike in activity.

To prevent this, it’s important to split your recipient list into smaller batches and send emails gradually with time intervals in between. Email providers monitor engagement metrics like opens and clicks. If these metrics are positive, a good sending reputation is built with mailbox providers, reducing the likelihood of future emails being marked as SPAM.

When do you need to warm up your domain?

If you’re using a new IP/domain combination for sending emails, you’ll need to properly warm up your IP to ensure inbox providers deliver your emails. This applies to all customers starting with Email Campaigns.

Warming up involves sending low volumes of email on your new IP/domain combination and gradually increasing the volume over time. This allows ISPs to recognize, identify, and evaluate your sending practices, ensuring you’re a legitimate sender.

A guide, including a detailed warm-up schedule, can be found here.

How to determine if warming up is successful?

When following the warming-up schedule, it’s important to check the statistics after every batch:

1. The bounce rate should be below 5%.

2. The complaint rate should be below 0.25%.

If these metrics are within acceptable limits, proceed to send the next batch. Continue monitoring the statistics between each batch.

What to do if you encounter deliverability issues?

If you experience deliverability issues during the warm-up phase (e.g., high bounce or complaint rates), follow these steps:

• Pause Sending or Reduce Volumes: Allow spam filters to adjust to the new IPs.

• Stop Sending to Problematic Mailbox Providers: If policy blocks occur, troubleshoot and fix the issue before resuming sending.

• Check Your Recipient List: Ensure you haven’t accidentally sent emails to:

  • Unsubscribed recipients.

  • A large number of unengaged subscribers.

If this happens, hold your sending volumes at the current level for a few days. Then, restart the warm-up plan and focus on sending to engaged subscribers first.

For more information on email deliverability, check out our documentation.

Video

Below you find a video on the importance of warming up your domain.