Email warmup
Mailboxes that warm each other up.
Turn on warmup and your connected mailboxes start a quiet, natural conversation with each other, building the sender reputation your campaigns depend on. Included on every plan.
Warmup · alex@yourco.com
Example
Inbox rate
96%
Saved from spam
11
Replies
34%
Every day, automatically
What warmup does while you work.
Each mailbox runs on its own time zone and its own schedule. You don't have to touch a thing.
- 01
Plan the day
Each morning we plan the mailbox's warmup emails, pick partners from your other mailboxes and spread send times across working hours (8:00 to 19:00 by default).
- 02
Send naturally
Emails go out from the real account with varied, business-style wording. No links, no images, no tracking pixel and no hidden markers in the headers.
- 03
Find and rescue
The receiving mailbox finds each email and records where it landed: inbox, spam or promotions. Anything in spam is moved back to the inbox.
- 04
Engage and tidy up
Emails are opened, some are flagged important or starred, and about a third get a reply in the same thread. Then they're archived.
The ramp
Slow and steady, then steadier.
Volume grows a little each day and never in a straight line. If a mailbox starts landing in spam, the ramp waits for it to recover instead of pushing harder.
- Starts at 3 emails a day and adds about 2 a day, up to 30
- Daily volume varies by up to 15% and halves at weekends
- Holds steady if fewer than 70% of emails reach the inbox over 3 days
- Every setting is adjustable on Turbo and above
Example ramp
Campaign ramp
New mailboxes earn their volume.
A brand-new mailbox that sends hundreds of cold emails in week one is the fastest way to burn it. While a mailbox warms up, Mailnitrix caps how many campaign emails it can send and raises the cap day by day.
- No campaign emails for the first 2 weeks of warmup
- From day 14: 10 campaign emails a day, plus 5 each day
- The cap lifts once it reaches the mailbox's normal daily limit
- Mailboxes already sending regularly skip the ramp automatically
Campaign emails allowed per day
Visibility
See exactly how each mailbox is doing.
- Inbox rate over the last 7 days
- Emails saved from spam and replies sent
- Today's warmup target, sent so far and campaign cap
- A 30-day history chart per mailbox
- Clear errors when a mailbox can't log in
Requirements
What you need.
- Two or more mailboxes, or one with the shared warmup network
- Gmail, Google Workspace, Outlook.com or Microsoft 365
- IMAP access, so warmup can read and rescue mail
- A few minutes to switch it on per mailbox
Also included
- Shared warmup network on every plan
- Premium warmup pool on Nitro
- Custom warmup pools on Enterprise
FAQ
Warmup questions.
How long does warmup take?
Plan on two to three weeks before a new mailbox sends campaigns at full volume. By default the campaign ramp starts on day 14. Keep warmup running after that; it continues at a steady level alongside your campaigns.
Do warmup emails count toward my monthly emails?
No. Warmup is unlimited and never counts toward your plan. It does count toward each mailbox's own daily limit, so a mailbox's total volume stays safe.
How many mailboxes do I need for warmup?
Warmup runs between the mailboxes in your own account, so connect at least two; four or more works best. On every plan, including Spark, you can also opt a mailbox into the shared warmup network, so even a single mailbox can warm up.
Will warmup emails clutter my inbox?
No. After a warmup email has been read and handled, it's archived out of the inbox, so your real conversations stay easy to find.
Can Google or Microsoft tell it's warmup?
We avoid the obvious fingerprints: no tracking, no tags in the headers, varied wording and irregular timing at modest volumes. No warmup method can promise to be undetectable, which is why the ramp stays conservative.
Which providers does warmup support?
Gmail, Google Workspace, Outlook.com and Microsoft 365. Gmail mailboxes also report Promotions placement; Outlook mailboxes rescue mail from the Junk folder.
Warm up your mailboxes for free.
1,000 emails every month on the free plan. No credit card, no time limit.