Connect and pass pre-flight
We check SPF, DKIM, DMARC and MX before a single warmup message moves. A domain that cannot authenticate is fixed first, not warmed toward a result it cannot reach.
Deliverability you can verify
Warm your domain. Prove it from the outside.
Build sender reputation with realistic correspondence, then see exactly where messages land—measured outside our warmup network.
No card for the audit · Mailbox and relay modes · EU-hosted
Measured against:
Gmail
Microsoft 365
Yahoo
Zoho
Amazon SES
Sendgrid
The warmup problem
Most tools tell you what their own network saw.
That is useful activity data, but it is not independent placement evidence. Warmproof keeps its seed measurement infrastructure apart from the mailbox pool so the score can only improve when your messages genuinely land better.
Compare the differenceA calmer way to warm
Three steps. No black box.
Build reputation carefully
Persona-consistent correspondence is sent at realistic times, opened, read and answered with natural latency. Mailbox mode never exceeds 50 interactions a day per mailbox.
Prove it from outside
Independent seed mailboxes record where mail lands by provider: Primary, Promotions, Spam or missing. The people warming your domain never grade their own work.
Built for both sending models
Your inbox, or your sending service.
Mailbox mode warms a real inbox with two-way correspondence. Relay mode warms a sending domain or dedicated IP for services such as Amazon SES, SendGrid, Mailgun and Brevo—without pretending an inbox exists.
Explore both modes50/dayhard mailbox-mode cap
2first-class warmup modes
0shared seed reputation
∞maintenance after ramp
Start with the facts