How it works
A sending history for your domain, built the way providers want to see it
New domains land in spam because mailbox providers have never seen them send. WarmEnvelopes fixes that with slow, consistent, real sending — not with a fake engagement network.
1
Connect your Resend account
Warm-up mail is sent through your own Resend account, from your own domain — you stay in control of every message.
2
Add a domain and your inboxes
Add the domain you want to warm, paste the API key, and list inboxes you control as recipients.
3
The ramp runs by itself
A scheduler sends a few emails a day, spread across the day, and gradually increases the volume — building a natural sending history.
The details, honestly explained
Every part of the system, including the parts where domain warmup has limits.
Why warm up a domain at all?Mail filters treat a domain with no sending history as close to a bad one. What happens to a cold domain's first campaign, and what warming changes.How the ramp-up schedule worksThe formula behind each day's sending target, how a 30-minute scheduler spreads sends across the day, and how it compares to published ESP ramps.The 1,000+ template library: why warm-up content must varyIdentical warm-up emails get fingerprinted as bulk mail. How a library of 1,000+ distinct messages keeps warm-up traffic looking human.Why WarmEnvelopes sends to your own inboxes, not a networkHow peer warmup networks simulate engagement, what happened to GMass in 2023, and why WarmEnvelopes only sends real mail to inboxes you control.How the Resend integration worksVerify your domain, paste your Resend API key, and WarmEnvelopes sends warm-up mail through your own account. Quotas, mechanics, and Resend's stance.What WarmEnvelopes doesn't doThe honest limits of email warm-up: no faked engagement, no guaranteed inbox, no fix for bad DNS or bad lists. Why we tell you anyway.