Warming exchanges realistic emails between your mailbox and Winnr's warming network, with replies and positive engagement, so Gmail, Outlook and other providers see a normal, well-behaved sender. Volume starts low and ramps up to your daily target (up to 20 warmup emails a day). Warm a new mailbox for at least 2 weeks before cold sending, and 4 weeks on a brand-new domain. It costs $0.60 per mailbox per month.
What warming actually does
Every sending mailbox builds a reputation with each major email provider (Gmail, Microsoft 365, Yahoo, iCloud). A new mailbox has no history, so providers treat its first messages with extra caution.
Warming builds that history with clean, positive-engagement email:
- Volume ramp: start low and grow gradually. A mailbox that jumps from nothing to 100 emails a day looks suspicious.
- Realistic content: messages that read like normal correspondence.
- Positive engagement: warmup messages get replies and positive actions from the warming network, which are good reputation signals.
- Steady cadence: sending consistently every day, not in bursts, matches how legitimate senders behave.
After a few weeks of this, the mailbox has a track record. When you switch on real cold campaigns, filters treat it as an established sender.
The volume curve
Warming volume starts at a few emails a day and climbs to your daily target (up to 20). How fast it climbs depends on the ramp-up speed you pick:
- Slow: the most gradual. Best for brand-new domains.
- Normal: the default.
- Fast: the quickest, for established domains.
You can also turn ramp-up off for a mailbox, in which case it sends at its daily target straight away. That's only sensible for mailboxes that already have a sending history. Change these per mailbox in Warming settings.
When warming isn't enough
Warming builds reputation, but it can't overcome:
- Bad content. Spammy subject lines, all-caps text or manipulative openers get filtered even from warmed mailboxes.
- Too much volume too fast. Keep cold sending to 10 to 20 per mailbox per day, and total sending (cold plus warming) to 50 a day or less.
- Bad lists. Sending to invalid addresses generates bounces, which hurt reputation quickly. Verify your list before sending.
- Spam complaints. Recipients marking your messages as spam is the most damaging signal there is. A small complaint rate can undo weeks of warming.
Warming is necessary but not sufficient. Combine it with clean lists, good copy and a gradual campaign ramp.
Warming yourself vs. buying pre-warmed
Two paths to a warmed mailbox:
- Buy or connect a domain and warm it yourself. Create mailboxes, enable warming, wait 2 to 4 weeks. Cost: $0.60 per mailbox per month for warming (while it's enabled) plus the one-time domain cost.
- Buy pre-warmed from the marketplace. Skip the warming period. Cost: $3 per address per month, no minimum term.
Pre-warmed is faster; warming yourself is cheaper over time. See Pre-warmed marketplace.
What's next
Frequently asked questions
Do I really need to warm?
For a new mailbox on a new domain, almost always. Sending cold email from a brand-new mailbox with no history is the fastest way to land in spam and damage the domain's reputation for the long term.
What if the domain is already aged?
Aged domains usually warm faster, and a Fast ramp can suit them. A domain that has already been sending clean email for months may not need warming at all. Pre-warmed domains from Winnr's marketplace are sold already warmed, so you can start sending without a warming period.
Is Winnr's warming safe?
Warming traffic is designed to look like normal correspondence and stays inside Winnr's warming network. That said, email providers change their filtering over time, and no warming service can promise permanent results.
How long should I warm?
At least 2 weeks before cold sending, and 4 weeks is better on a brand-new domain. After that you can start real campaigns at low volume and keep warming running alongside if you want extra safety.
Can I warm and send cold at the same time?
Yes, most customers do once the initial warming period is over. Start real cold email at 10 to 20 per mailbox per day while warming continues, and keep total sending (cold plus warming) at 50 a day or less per mailbox.
Can the Winnr Agent manage warming for me?
Yes. The Winnr Agent in the app's chat panel can enable, pause, resume or disable warming and report on your warming mailboxes. Changes wait for you to click Confirm.