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How warmup works and how to start it

How mailbox warmup ramps up, recommended limits, and to keep it running.

Warmup gradually builds your mailboxes' sending reputation before you start cold outreach.

How it works

Once your mailboxes are set up, warmup ramps the daily volume up over roughly two weeks so the mailboxes build a healthy history before you scale into real campaigns. Keep warmup running continuously — pausing it interrupts that reputation-building.

Do I need to start warmup myself?

Yes. Buying mailboxes does not automatically start warmup, and Maildoso does not run a background or managed warmup pool on your behalf. Warmup runs through the sequencer you connect your mailboxes to (for example Instantly or Plusvibe — both have good warmup pools). Turn warmup on inside that tool and keep it running.

Recommended daily limits

A safe target once mailboxes are ready is around 80 emails per mailbox per day total — for example ~50 warmup + ~30 outreach — rather than maxing out a single mailbox. See What's the daily email limit per email account? for the exact limits.

A note on "Premium warmup"

The older Premium AI Warmup add-on is no longer offered to new accounts and is not being applied to mailboxes. If your dashboard shows a premium-warmup flag you can't interact with, treat it as inactive and warm your mailboxes through your sequencer as described above.

For questions about whether your warmup is performing well (inbox placement, reply rates), contact support so our deliverability specialist can review your account.

Related video

📹 How to Scale to 100K Emails/Month Without Killing Deliverability — how teams set up infrastructure, warm mailboxes, and spam-test to scale volume safely.

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