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Warm-up best practices

What is a warm-up?

Warm-up is the process of gradually sending emails from a new or unused email address to build its reputation with email providers like Gmail, Outlook, Yahoo, and others.

Mailmeteor automates this by sending a small number of emails every day to a trusted network of real inboxes that will open, reply, forward, and interact with your messages. These positive signals show email providers that you’re a legitimate sender, which helps your emails avoid spam filters.

Why and when should you use it?

You should use warm-up when:

  • You’re sending from a new domain or email address.
  • Your address hasn’t been used in a while.
  • You’re planning to send emails at higher volumes than before.
  • You’ve had deliverability issues in the past (e.g. landing in spam).

If you’re unsure whether you need to warm up, you can check your sender health using our free Email Reputation tool. It runs a quick analysis of your DNS records, blacklist status, and spam signals. If your score is below 50, we strongly recommend starting warm-up before launching any real campaigns.

How long should you keep it active?

We recommend keeping warm-up active for at least 30 days. This period allows your sending volume to increase gradually and helps email providers build trust with your address.

Here’s what that typically looks like:

  • Days 1–3: just a few emails per day
  • Days 4–10: volume starts to increase
  • Days 11–30: stable daily activity (~40–50 emails/day)

You can begin sending real emails such as cold outreach or newsletters after the first 10–14 days, once your warm-up volume has started to climb. But it’s important to go slowly: send to a small, high-quality segment of your list first, and gradually scale from there. Avoid sending high volumes too early, as that can damage your reputation before it’s fully established.

For best results, we recommend keeping warm-up active for 60 to 90 days. This helps reinforce your reputation even while you begin real outreach. Think of it as running in the background. Mailmeteor continues to generate activity that boosts trust while you scale up safely.

If you stop sending for a while (e.g. after a pause in outreach), consider restarting warm-up for a week or two to refresh your reputation before sending again.

Next steps

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