Why new mailboxes need warming up
Mailbox providers decide where your email goes partly on the history of the domain and address sending it. A new domain has no history, so providers watch it closely: how many messages it sends, how many bounce, how many people mark them as spam and how many reply. Sending a small, steady amount of relevant email builds a good sender reputation. A sudden burst does the opposite.
A typical warmup schedule
Most ramps start with a handful of emails a day and rise over several weeks. BacklinkGenie's managed mailboxes start at 4 emails a day, add 2 every other day, and reach their ceiling of 35 a day after about 32 days. The mailbox warmup calculator shows the same ramp day by day and what it means for monthly volume.
Keep the ceiling low even after warmup. Cold outreach is one-to-one email, and a mailbox sending a few dozen personal messages a day looks like a person, not a campaign.
Manual ramp vs warmup tools
Warmup tools connect your mailbox to a pool of other inboxes that send each other automated messages, open them and pull them out of spam. That creates engagement, but it's artificial, and it doesn't replace a sending pattern built on real email to real people. A slow manual ramp of genuine, relevant messages is the part that matters most.
What warmup can't fix
Warmup only works on a correctly set-up domain. Google's sender guidelines require every sender to set up SPF or DKIM, and bulk senders, defined as those sending close to 5,000 or more messages a day to personal Gmail accounts, need SPF, DKIM and DMARC. Google also asks senders to keep the spam rate reported in Postmaster Tools below 0.3%. Yahoo publishes similar requirements.
- Publish SPF, DKIM and DMARC before the first email. The record generator and checker help.
- Verify addresses so you don't bounce.
- Write emails people won't report: one recipient, one specific reason, no links or attachments in the first message.
- Send from a separate outreach domain, never your main company domain.
How BacklinkGenie warms mailboxes
On a paid plan BacklinkGenie registers a domain close to your brand, sets up a Google Workspace mailbox with SPF, DKIM and DMARC, and holds sending until the records pass. It then follows the ramp above, pauses a mailbox automatically if bounces rise, and keeps a suppression list so bad addresses are never retried. Cold email from Google Workspace and the deliverability guide explain the reasoning.
Example
Margin's new outreach mailbox sends 4 pitches on day one, 10 by the end of week one, and reaches 35 a day about a month in.
Putting it into practice
Where to use it: Mailbox warmup calculator and Email deliverability for link outreach. For the longer version, read sending cold outreach safely from Google Workspace.