How warmup works

Warmup is the part of Warmerly that builds a mailbox's sending reputation before you use it for real outreach. It is a separate system from campaigns, and the single most common misunderstanding about it is worth stating first.

Warmup never emails your prospects

A mailbox in warmup does not send cold email to anyone on your lists. It exchanges ordinary-looking email with other mailboxes inside Warmerly's private warmup network:

your mailbox sends warmup messages to network peers,
peers send warmup messages back to your mailbox,
both sides open and reply to a tuned share of what they receive.

That two-way traffic is what mailbox providers read as "this address is used by a real person who gets real replies." It is invisible to your prospects, and it is the reason warmup works at all — one-directional sending into a void builds nothing.

Real outbound to real leads happens only through Campaigns. The order that works is: connect the mailbox, authenticate the domain, warm it up, then point campaigns at it.

The ramp

Warmup starts small and increases the mailbox's daily volume over time rather than sending its full allowance on day one. A brand-new address that suddenly sends dozens of messages looks exactly like a compromised or purchased one, so the ramp is doing reputation work even on the days it looks slow.

Two numbers bound a mailbox's volume:

Setting	What it does
Daily sending limit	The mailbox's own ceiling for campaign sends per day. New mailboxes default to 30/day.
Ramp	While a mailbox is still ramping, the effective daily figure is lower than that ceiling and climbs toward it.

You can raise a mailbox's daily limit on the mailbox's own settings, but raising it does not skip the ramp — deliverability is earned over days, not set in a field.

How long should warmup run? Two weeks before real sending is a reasonable floor for a new address, longer for a brand-new domain. Keep warmup enabled after campaigns start: it is not a setup step you finish, it is the background activity that keeps the mailbox healthy.

Reputation is cross-provider

Your mailbox can be hosted anywhere — Google Workspace, Microsoft 365, Zoho, IONOS, your own server. The warmup network itself is spread across many providers, so the activity your mailbox takes part in is seen by Gmail, Outlook and the rest regardless of who hosts the sending address. Where your mailbox is hosted does not limit which providers learn to trust it.

Two different "reply rates"

These look like the same metric and are not. Mixing them up is the second most common warmup question we get.

Where you see it	What it measures
Warmup reply rate (7d) / Warmup open rate (7d) on a mailbox's page	Activity inside the warmup network only — how often peer mailboxes opened or replied to warmup mail. Internal, tuned, and says nothing about your prospects.
Reply rate on a campaign's page	Real leads replying to your real outbound. This is the number that reflects your outreach.

So a 60% "warmup reply rate" is not a prediction of campaign performance, and a quiet campaign reply rate is not a warmup fault.

Checking it is working

Run a placement test from the mailbox's Placement tab. It sends probe emails through that mailbox to seed addresses across providers and reports where each one landed — inbox, promotions or spam. That is the direct answer to "is this mailbox healthy," and it is worth more than any single rate on a dashboard.

LinkedIn warmup is a different mechanism

LinkedIn warmup is not email warmup pointed at another channel. There is no peer network: Warmerly automates real activity on your own connected LinkedIn account — posts, reactions, comments, profile views and connection invitations — generated from the topics, industries and guidelines you configure under Accounts → your LinkedIn account → LinkedIn warmup settings.

It requires a paid LinkedIn slot (LinkedIn is sold per account, separately from the base plans — see Plans and limits).

Warmup and your plan

Warmup is included on every plan, Free included, and warmup traffic is never metered against a sending allowance. What bounds warmup is how many mailboxes your plan lets you connect.

One exception worth knowing: while a workspace is locked out for billing, warmup stops along with campaign sending until the lock clears. Campaigns are not reset, and both resume by themselves within a few minutes of the workspace getting back inside its plan.