A new domain has no reputation. Give it 21 days.
Google and Microsoft filter new domains with no reputation, so no one trusts you and you cannot send at scale for months. MailStrike builds the reputation first: an AI Agent on each mailbox, real threads in the MailStrike network, full volume by day 21.
Send from a cold domain and you go to spam. Warm it first and you are sending in three weeks.
Send real campaigns from day one and they hit spam, teaching Google and Microsoft that your mail is not wanted. That history takes months to repair.
MailStrike builds the reputation before you send a single campaign: real threads in the MailStrike network until providers record a trusted sender, full volume by day 21.
Checked on connect. With the exact record to publish.
Authentication is the entry ticket and warming builds on top of it. A new domain usually has one record missing, and MailStrike shows you which, with the value to paste into DNS.
- No password shared.
Connect with a click. Access is revocable from your Google or Microsoft account.
- Google-verified and lab-assessed.
To our knowledge the only standalone warming tool that passed Google's OAuth verification and a CASA Tier 2 assessment.
- Your inbox stays clean.
Warming mail is labeled and archived on arrival. Your team never sees it.
Day 22. Start sending. Warming carries on underneath.
Your outreach leaves from the same mailboxes. The agent keeps replying, rescuing, and reading in the background, so the reputation it built keeps holding while you send.
Daily volume and the ramp are your settings. MailStrike never exceeds them, and the dashboard tells you how much you can safely send each day.
The defaults are right for most teams. Connect the mailbox, start sending on day 22, and look at the dashboard when you want to scale.
Two minutes to connect. Nothing you have to do after that.
- One click, or an app password.
Google Workspace and Microsoft 365 connect through OAuth. Everything else connects over SMTP and IMAP.
- Hidden on arrival.
Warming threads are labeled and archived the moment they land. Your inbox shows only your real mail.
Google WorkspaceOne click · OAuth
Microsoft 365One click · OAuth
Anything elseApp password · SMTP
PostNitroCase studyHalf their mail to Google was in spam. They had no idea.
One Free Deliverability Test found it. Eleven days of warming took PostNitro from 67% to 100% inbox placement at Google, and it has held since. Read the case study →
Half the Google audience they were paying to reach never saw them. Found by a free test, fixed in 11 days.
Questions that come up most.
What this page raises, answered plainly.
Can't find it here? Ask the team.
21 days to full volume on the default ramp, with noticeable improvement around two weeks. Warming then continues at about 15 to 25 emails a day so the reputation holds.
Keep real outreach low until the dashboard says the mailbox is safe to send from. Once it does, start at 20 to 30 sends a day per mailbox and scale from there while warming carries on underneath.
Warming starts at a few threads a day and climbs to full volume over the ramp. You never need to set it by hand. The defaults are right for most teams.
Most teams do, to keep the main domain's reputation out of outreach. Each new domain needs its own 21 days, and the mailboxes on it each get their own AI Agent.
Providers filter new domains with no reputation, so early mail goes to spam and the domain learns a bad history. Repairing that takes longer than warming it properly first.
At least three per domain, each agent on a different persona, so receiving providers see a team of distinct people rather than one script repeated.