Cold mailboxes, warmed up properly.
Warmflow builds sender reputation for Gmail and Microsoft 365 mailboxes with real threaded conversations, rescues anything that lands in spam, and grows the ramp a little every day. So when your campaign starts, providers already know who you are.
Twenty-two dots from cold to ready.
Inbox providers judge a mailbox on its history. A new one has none, so its first cold email looks exactly like spam. Warmup gives it a history worth judging. Here's what happens, in order.
Connect it, and we read your DNS straight away.
Connect a Google Workspace or Microsoft 365 mailbox. Before a single warmup email goes out, Warmerly checks the domain's SPF, DKIM, DMARC, MX and blocklist status, because warming a mailbox with broken authentication just warms up the problem.
Real threads, with quoted replies.
Warmflow starts small: a handful of conversations a day between your mailbox and peer mailboxes. They reply in-thread, quoting the message before, the way people actually write. Providers see a mailbox that holds conversations, not one that fires and forgets.
Anything in spam gets moved back.
If a warmup message lands in a peer's spam folder, that mailbox moves it to the inbox. Each rescue is a signal to the provider that the message was wanted, and it tells you early where your reputation is weakest.
with ines@coastallabs.coRescued from spam
Volume grows on a schedule, and backs off when it should.
Each day's limit comes from the ramp, the provider's ceiling and the mailbox's health, and the app shows the working: you can always see why today's number is what it is.
A full W means ready to send.
When warmth and placement hold, the mailbox shows Ready and can carry campaigns. Not on a fixed date: when the numbers say so. The full W is our logo for a reason.
Warmup
The daily warmup loop.
Your mailbox emails other mailboxes, they reply, spam is moved back to the inbox, and the volume grows a little each day.
One ramp. Watch the dots.
Every mailbox follows the same curve: 4 a day at the start, 50 a day by day 30. Gmail mailboxes stop at 40 a day and Outlook at 30. Pick a provider to see where yours stops.
Out of spam, into the thread.
Two signals do most of the work. Replies in a real thread tell providers people talk to you. Rescues from spam tell them your mail was wanted even when a filter disagreed.
Each reply carries the previous message underneath, so threads grow the way human ones do.
See which conversations were pulled from spam and from which provider. A cluster of rescues is an early warning.
Warmup tells you the trend; placement tests tell you where a real email lands today.
New mailboxes learn from old ones.
Two brand-new mailboxes chatting to each other prove very little. Warmflow peers your mailbox with aged mailboxes that already have a history with the big providers, so the early signals come from senders providers already trust.
Peers reply in-thread with the earlier message quoted, so the history looks like people talking.
A new mailbox starts at 4 a day and sends a little more each day, up to 50 a day by day 30.
If a peer's filter catches your message, the peer moves it back to the inbox and the rescue is logged.
Every mailbox explains itself.
Warmth, placement, today's limit and authentication, per mailbox, with the reason behind each number. If something's wrong, it says what and links to the fix.
- Day 14 on the warmup ramp25
- Outlook allows up to 30 a dayunder cap
- Last placement test held at 88%no change
Every dot
is a degree.
Need more sending mailboxes?
OneMail is Warmerly's hosted mailboxes: we set up the domain records and start warmup on every one. Ready-warmed mailboxes are also offered when some are in stock. And every new account gets a free sandbox mailbox that's already warming, so you can watch the whole process before connecting your own.
Hosted by us, warming from day one.
Priced per mailbox, on top of your plan. They never use one of your plan's mailbox slots.
A sandbox mailbox, already warming.
Open the app and it's there: a real mailbox that starts warming on day one, at a gentler pace than the standard ramp, so you see warmth, threads and rescues before you connect anything of yours.
Warm, check, then send.
Know you'll land.
Seed-inbox placement tests by provider, and daily SPF, DKIM, DMARC, MX and blocklist checks with the exact record to fix.
See placement and DNS →Next · Cold emailThen send cold email that lands.
Campaigns and sequences from your warmed mailboxes, with pre-launch checks, {{ai_opener}} and one Inbox for replies.
See cold email →Start with one mailbox. Watch it warm.
Free plan: one mailbox, capped sends. Paid plans from $19 a month with unmetered sending.
- Free plan, no time limit
- 7-day trial on paid plans
- 30-day inbox guarantee, with conditions
- Customer data is hosted in the EU
Every signup gets a free sandbox mailbox that's already warming.