Free Email Warmup for Every Mailbox
Alienmail warms up every mailbox you add, bought or connected, at no cost. It builds your sender reputation before you send cold email, so your campaigns land in the inbox instead of spam.
- Free on every mailbox
- No inbox limit
- Warmup emails never use credits
What Is Email Warmup?
Email warmup is the process of slowly raising how much you send from a new mailbox, while building up real-looking replies and opens, so inbox providers learn to trust it. Without it, a new mailbox that suddenly sends a few hundred cold emails looks like spam and gets filtered. Warmup builds that trust over 2 to 3 weeks before your first campaign.
How Alienmail Warms Up Your Mailbox
Add a mailbox
Buy a Gmail or Outlook mailbox in Alienmail, or connect your own Google Workspace, Microsoft 365, Zoho or SMTP inbox. Warmup starts the day you add it.
Alienmail exchanges real emails
Your mailbox sends, receives, opens and replies to messages with other mailboxes in Alienmail's warmup network, so the activity looks like normal correspondence.
Volume ramps and reputation builds
Daily volume rises gradually while Alienmail tracks where your emails land and your sender health, so you know when the mailbox is ready for cold email.
A Typical Email Warmup Schedule
A new domain usually needs 2 to 3 weeks of warmup before full campaigns. Here's a typical ramp Alienmail follows for one mailbox. Your pace may differ with the mailbox's age and provider.
| Week | Warmup emails/day | Cold emails/day |
|---|---|---|
| Week 1 | 2 to 10 | None |
| Week 2 | 10 to 25 | 5 to 10 |
| Week 3 | 25 to 35 | 15 to 25 |
| Week 4 and on | 35 to 50 | 30 to 40 |
Keep warmup running after week 4. It keeps your reputation steady while you send.
Warmup That Costs Nothing, on Every Mailbox
Standalone warmup tools charge $25 to $49 per inbox per month. Alienmail includes warmup free on every mailbox, bought or connected, with no inbox limit. Warmup emails never use your credits. You pay only for the cold emails you send.
Alienmail warmup
$0
per mailbox, every month, no inbox limit
Alienmail vs Standalone Email Warmup Tools
Most warmup tools charge per inbox per month. Alienmail includes it.
| Alienmail |  Instantly |  Mailreach |  Warmy.io | |
|---|---|---|---|---|
| Warmup price | Free, every mailbox | On paid plans | Per inbox/mo | Per inbox/mo |
| Inbox limit | Unlimited | Varies by plan | Per inbox | Per inbox |
| Sends cold email too | Yes | Yes | No | No |
| Monthly fee | None, pay per email | From $47/mo | Warmup only | Warmup only |
Prices from each tool's pricing page, checked October 2026.
Last updated: October 2026Warmup Works Best With SPF, DKIM and DMARC
Warmup builds trust, but inbox providers also check that your domain is set up correctly. For mailboxes you buy in Alienmail, SPF, DKIM and DMARC are set up for you. For mailboxes you connect, Alienmail checks all three and shows you what to fix.
Email Warmup FAQ
Email warmup slowly raises how much a new mailbox sends while building real replies and opens, so inbox providers trust it. It's the step that keeps your first cold campaigns out of spam.
Start Warming Your Mailboxes Free
Add a mailbox and warmup starts today. No per-inbox fee, no card.