Where this lives. Sign in and open /accounts in the app.
What it does
Warmup does not have its own page. It lives inside Accounts, in the Warmup column and the bulk warmup controls, and on each mailbox's own page under its Warmup tab. It slowly raises a mailbox's sending volume by exchanging real mail between the mailboxes already in your own workspace, so a mailbox builds sending history with Google, Microsoft, or your own mail servers before real prospects ever see a message from it.
Before you start
- A mailbox needs an active connection (or, for a tenant-provisioned mailbox, send authorization) before warmup can start.
- Starting warmup needs the "manage_provider_connections" permission, and a manually requested start needs approval before it actually begins.
- Plan for roughly two to three weeks before a fresh mailbox is fully warmed. The recommended sending load once campaigns start is 8 to 10 cold emails per mailbox per day.
Set it up, step by step
- From Accounts, click Warm up on a ready mailbox, or, from the mailbox's own page, Request warmup. Either one stages an approval; nothing sends until it is granted.
- To start warmup on many mailboxes at once, select them on Accounts and click Start warmup. One approval covers the whole selection, and any stale single requests for the same mailboxes are superseded automatically.
- A newly connected, sendable mailbox with no warmup plan yet is often picked up on its own by an automatic check, unless a person has explicitly paused it.
- Optionally set a shared ramp target for a selection: type a number in the warmup-per-day field and click Set warmup/day. This also becomes the default target for mailboxes that start warmup later.
- To pause one mailbox's ramp, use Pause warmup from its row or its own page. To pause several, select them and click Pause warmup in the toolbar.
- To resume a mailbox you paused yourself, click Start warmup again. This restarts the ramp from the provider's floor rather than from where you left off, so treat a self-triggered pause as a real reset.
What you should see
- Warmup begins at the provider's floor: 5 a day for Google Workspace and Microsoft 365, 4 a day for other OAuth providers, 3 a day for SMTP/IMAP mailboxes you connected yourself, and 2 a day for mailboxes on your own self-hosted mail servers.
- The Warmup column shows a trust score, the current status such as running or paused, and "today toward target per day."
- Volume climbs only on real evidence. A mailbox needs actual warmup sends in the last 48 hours before it is allowed to move to the next step, so a quiet mailbox holds instead of climbing on a timer alone.
- The Deliverability page's "Warmup network, live activity" panel shows real conversations between your own mailboxes: sent, opened, rescued from spam, replied to, and the inbox rate that warmup mail actually achieved.
- When the ramp finishes, the plan shows complete and the mailbox returns to ready. Finishing does not unlock full volume in one step. It raises the mailbox's baseline, and a separate reputation system then walks the live daily cap up toward that baseline in roughly 25 percent steps a day while outcomes stay healthy, and pulls it straight back down if they do not. That gradual walk-up is the maintenance level after the ramp.
Common problems
- Warmup pauses itself automatically on a dead token, a blocklisted mailbox or domain, elevated bounce or spam risk, or a low provider throttle score. It holds volume, without pausing, when SPF, DKIM, or DMARC is not fully verified yet, or when health drops below 60.
- An automatic pause resumes itself one ramp step below where it paused, once the blocker clears. A pause you triggered yourself stands until you restart it.
- Warmup traffic never appears in the master Inbox. It is recorded to its own internal log, never to the messages the Inbox reads, and it only ever runs between mailboxes already in your own workspace, never to outside addresses.
- A mailbox on a domain with no working mail server, or one producing a flood of "recipient unreachable" bounces, is excluded from warmup until mail can reach it again. Nothing about the mailbox is removed, and this is surfaced once a day rather than silently.
- Warmup is refused outright, not run for show, on a mailbox that cannot currently send at all.
Related
How does email warmup work?
Warmup sends conversation-shaped mail between real mailboxes that reply, and rescues anything that lands in junk. The rescue is the signal that teaches the filter. A warmup that only sends is a warmup that only looks busy.
How long does email warmup take?
Two to three weeks from the provider floor to the mailbox's cap. There is no honest way to shorten it: a pre-warmed mailbox bought from a vendor carries someone else's history, usually on a domain you do not own.
Do email warmup tools really work?
They build a sending history, which is what a filter reads when it decides where the next message goes. What they cannot do is fix a domain with no authentication, a bought list, or a complaint rate above 0.1 percent. Warm-up is a floor, not a remedy.
Does warmup traffic count against my daily sending limit?
Yes. Warm-up and campaign traffic share the same per-mailbox daily number, so a mailbox warming at eight a day has room for two campaign sends, not ten. This is the most common reason placement falls right after a warm-up finishes.
Does warm-up mail appear in my inbox?
No. Warm-up traffic never reaches the master inbox, so your replies view stays real.
Read next
Common questions
How does email warmup work?
Warmup sends conversation-shaped mail between real mailboxes that reply, and rescues anything that lands in junk. The rescue is the signal that teaches the filter. A warmup that only sends is a warmup that only looks busy.
How long does email warmup take?
Two to three weeks from the provider floor to the mailbox's cap. There is no honest way to shorten it: a pre-warmed mailbox bought from a vendor carries someone else's history, usually on a domain you do not own.
Do email warmup tools really work?
They build a sending history, which is what a filter reads when it decides where the next message goes. What they cannot do is fix a domain with no authentication, a bought list, or a complaint rate above 0.1 percent. Warm-up is a floor, not a remedy.
Does warmup traffic count against my daily sending limit?
Yes. Warm-up and campaign traffic share the same per-mailbox daily number, so a mailbox warming at eight a day has room for two campaign sends, not ten. This is the most common reason placement falls right after a warm-up finishes.
Does warm-up mail appear in my inbox?
No. Warm-up traffic never reaches the master inbox, so your replies view stays real.
Read next
Last updated September 19, 2026. Written by the team that operates the platform.