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Email warm-up: what it is and a safe schedule

A new mailbox or domain has no sending history, so you raise its volume gradually. Here is what warm-up is, a cautious example schedule, and what to watch while you ramp up.

Warm-up means sending a small number of ordinary emails at first, then more each week, while bounces stay low and recipients treat your mail as wanted. Mailbox providers learn from that history. A day-old domain that suddenly sends a whole list looks like spam, however good the message is.

Before you warm up

  • Set up SPF, DKIM and DMARC: see the guides for SPF and DKIM and DMARC on Google Workspace.
  • Verify your list. Bounces are what hurt a new mailbox most, so remove addresses that do not exist before the first send.
  • Put an unsubscribe link in every email and honor it quickly.

An example 4-week schedule

  • Week 1: 5 to 10 emails a day.
  • Week 2: 10 to 15 a day.
  • Week 3: 15 to 25 a day.
  • Week 4: 25 to 30 a day, then hold there.

Send on weekdays, at a steady pace through the day. To send more in total, add mailboxes and warm each one up, rather than pushing one mailbox past about 30 emails a day.

What to watch every day

  • Bounces. If they climb, stop, clean the list and restart lower. Do not push through.
  • Spam complaints. For Gmail, Postmaster Tools shows your spam rate. Google asks senders to stay below 0.30% and recommends under 0.10%.
  • Replies. Real replies are the best sign that your mail is wanted.

How SendPath helps

SendPath’s warm-up has a mailbox send a few ordinary emails a day to SendPath’s own seed mailboxes, which open them, rescue them from spam and reply. Your mailboxes only ever write to those seeds, never to other customers or your lists. By default it starts at 3 a day, adds 2 a day, and a mailbox is Ready after about two weeks once most of its warm-up mail reaches the inbox. The details are in the warm-up docs and on the warm-up feature page.

Common mistakes

  • Sending a full list from a domain that is a day old.
  • Skipping a week, then doubling the volume to catch up.
  • Changing the domain or mailbox in the middle of the ramp, which resets the history. The From address belongs to the history.
  • Ignoring bounces because the send “mostly worked”.

Related

See your setup before you ramp up.

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FAQ

Questions, answered

How long does email warm-up take?+

There is no official figure. Plan on a few weeks of gradual increases before you send at full volume from a new mailbox. SendPath marks a mailbox Ready after about two weeks of warm-up with healthy results.

Can I warm up a mailbox and send campaigns at the same time?+

Yes, as long as the campaign volume stays low and inside that day's limit. Warm-up keeps running at a lower volume on days the mailbox also sends campaigns.

Does an old mailbox need warm-up?+

If it has been idle for a long time, or you are about to raise its volume sharply, ramp up again. A mailbox that has been sending steadily and well does not need the slow start.

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