Warming exchanges realistic-looking emails between your mailbox and Winnr's warming network — replies, opens, forwards, and no-spam actions — for 2-3 weeks. This builds sender reputation with Gmail, Outlook, and other providers so when you switch to real cold campaigns, filters treat you as an established sender instead of a brand-new one. Volume ramps from a few emails/day on day one to full capacity (up to 20/day) by week 2-3.
What warming actually does
Every mailbox has a reputation score with each major email provider (Gmail, Microsoft 365, Yahoo, iCloud). New mailboxes have no score — they're neutral, which sounds fine but actually means providers apply extra scrutiny to their first few weeks of messages.
Warming builds that score by sending clean, positive-engagement email:
- Volume ramp — start low, grow gradually. A mailbox that jumps from 0 to 100/day looks suspicious.
- Realistic content — messages that read like normal correspondence, not obvious warmup phrases.
- Positive engagement — recipients open, reply, forward, and mark as "not spam." Each action is a positive reputation signal.
- Consistent cadence — sending steadily every day (not big bursts) matches how legitimate senders behave.
After 2-3 weeks of this, the mailbox has a reputation score with each provider. When you switch to real cold campaigns, filters treat it as an established sender and let more messages through to the inbox.
The volume curve
Rough, approximate shape of warming volume over about 3 weeks (full capacity is 20 emails/day):
| Week | Emails/day (approx.) | What's happening |
|---|---|---|
| 1 | a few | Baseline reputation building |
| 2 | ramping | Climbing as reputation stabilizes |
| 3 | up to 20 | Full warming capacity, mailbox is ready for real sending |
Exact numbers depend on your ramp-speed setting. Winnr's defaults fit most cases — you can adjust daily volume (up to 20/day) and ramp speed (Slow/Normal/Fast) per mailbox in Warming settings.
When warming isn't enough
Warming builds reputation, but it can't overcome:
- Bad content. Cold emails with spammy subject lines, all-caps text, or manipulative openings get filtered even from warmed mailboxes.
- High volume too fast. Even a fully warmed mailbox that jumps from warming volume (up to 20/day) straight to 200/day of real send gets throttled. Ramp real campaigns from 10-20/day to full volume over another 2-3 weeks.
- Bad targeting. Sending to invalid addresses generates bounces, which crater reputation. Verify your list before sending.
- Reply-to-spam ratio. Recipients marking your messages as spam is the single most damaging signal. Even a 1% spam rate can undo weeks of warming.
Warming is necessary but not sufficient. Combine with clean lists, good copy, and gradual campaign ramping.
Winnr warming vs. buying pre-warmed
Two paths to a warmed mailbox:
- Buy fresh + warm yourself. Purchase or connect the domain, create mailboxes, enable warming, wait 2-3 weeks. Cost: $0.60/mailbox/month for warming (billed while enabled) + one-time domain cost.
- Buy pre-warmed from the marketplace. Skip the warming period entirely — Winnr's marketplace domains were warmed at inventory time. Cost: $3/address/month, ongoing.
Pre-warmed is faster; warming yourself is cheaper long-term. See Pre-warmed marketplace.
What's next
Frequently asked questions
Do I really need to warm?
For a new mailbox on a new domain — yes, almost always. Sending 100 cold emails from a day-old mailbox will land in spam and damage the domain's long-term reputation. Warming for 2-3 weeks is the difference between 40% and 85% inbox placement in your first month.
What if the domain is already aged?
Aged domains warm faster. A 6-month-old domain that hasn't sent email still benefits from 1-2 weeks of warming. A domain that's already been sending clean email doesn't need it. Winnr's marketplace pre-warmed domains skip warming entirely — they were warmed at inventory time.
Is Winnr's warming safe? Some tools got shut down by Google.
Winnr's warming exchanges look like normal correspondence to email providers. It's been running continuously with no shutdowns. That said, providers do change their spam detection over time — no warming service can promise permanent safety.
How long does full warming take?
2-3 weeks is standard. A minimum of 10 days is required to see meaningful reputation improvement. Beyond 3 weeks, benefits taper — you're better off starting real campaigns at low volume and continuing to warm alongside if you want extra safety.
Can I warm and send cold at the same time?
Yes — most customers do. Once a mailbox is fully warmed (warming runs up to 20 emails/day), you can start sending real cold email at low volume (10-20/day) while warming continues in the background. Gradually shift the ratio toward cold as the mailbox proves clean.