Hive’s IP and domain warmup feature automatically manages how your emails are sent when you’re using a new custom subdomain.
At first, Hive gradually sends an increasing volume of email from your new subdomain, while routing the remaining volume through Hive’s shared domains (which already have strong reputations). This process ensures you build trust with inbox providers while still being able to send at scale.
If you’ve set up a custom subdomain in Hive, you may see a warmup-related message when sending an email.
Why is IP/domain warm-up necessary?
When switching email service providers or setting up a new custom subdomain, one of the biggest factors for deliverability is proving to inbox providers (like Gmail, Outlook, and Yahoo) that you’re a legitimate sender.
Warmup is how you build that trust. By gradually sending to engaged subscribers—those who regularly open and click your emails—you signal to inbox providers that your messages are wanted.
If you skip this process and blast your entire list right away, it looks suspiciously like spam. The result? Your emails are more likely to land in the spam folder or be blocked altogether.
Consistency is key: If you stop sending emails for an extended period, your domain may enter a cooling period. This means your reputation can weaken, and you may need to re-warm your domain before sending at full volume again.
Curious why emails land in spam? Check out this article for practical tips to keep your messages in the inbox.
How Hive’s automated IP/domain warm-up works
First send:
Hive selects 200 subscribers and delivers to them from your new subdomain. The rest of your volume is delivered through Hive’s trusted shared domains (e.g., @mail-1.hive.co, @mail-2.hive.co).Note: You still control your “From Name,” so your branding stays consistent.
Gradual increase:
Warm-up increases only on days you actually send emails. It does not progress on days with no sending activity.
Each sending day, Hive increases the amount delivered from your custom subdomain based on your highest sending day within the last 21 days. The ramp happens per day (not per individual send).
Your increase rate depends on volume:
2× per sending day if your last largest sending day was below 76,800 recipients
1.5× per sending day if your last largest sending day was 76,800 recipients or more
Early warm-up may look like this:Day 1: 200 emails from your custom subdomain
Next sending day: 400
Next sending day: 800
Then: 1,600, and so on
If you skip sending days, the warm-up simply pauses until your next campaign.Full transition:
Once your subdomain is warmed, all emails will be sent from your custom subdomain (not a Hive shared domain). Timeline depends on how often you send—more frequent ramp-ups warm faster; 1–2 sends/week will take longer.
Things to note
The exact split between your subdomain and a Hive domain isn’t shown in-app, but you can find it in the Email Stats export.
Stay consistent with your sending. Regular, healthy email activity is what keeps your domain reputation strong and prevents it from slipping back into a cooling period.
You don’t need to manually manage warmup—Hive handles it in the background.
While warming, your campaigns still go out at full volume, with the overflow safely sent from Hive’s high-reputation shared domains.
Once warmup is complete, you’ll enjoy stronger inbox placement and improved deliverability from your own branded domain.
If you’d like to add more than one subdomain to your account, please reach out to your Customer Success Manager or Hive’s Support team. This feature isn’t self-serve and must be reviewed and enabled by our team.
Can my custom subdomain go back into a "warm-up" phase?
Yes, this is by design to prevent large activity spikes that can hurt your subdomain’s reputation. Your subdomain’s sending limit is determined by your last 21 days of activity. If you haven’t sent in 21+ days, the domain is considered cold, and you’ll restart warm-up.
Warm-up progression always applies per sending day. If you skip days, progression pauses - but your last proven level remains in place (as long as you send again within 21 days).