What email warm-up is#
Warm-up is the practice of gradually increasing sending volume from a new domain or IP so mailbox providers can build a positive reputation profile before you reach full volume.
Why it matters#
Providers throttle or reject sudden volume from unknown senders. Skipping warm-up is the most common way new domains end up in spam permanently.
How mailbox providers use it#
Gmail, Microsoft, and Yahoo combine authentication results, sender reputation, and recipient engagement into a placement decision made per message. Email warm-up feeds directly into that model, and weaknesses compound with other signals.
How to measure the impact#
- Baseline inbox placement with seed tests before any change.
- Make one change at a time and hold volume steady.
- Re-test after 48 to 72 hours; provider models need time to update.
- Track Postmaster Tools and SNDS alongside your seed results.
Improving it#
- Start with 20 to 50 messages per day per mailbox to your most engaged, opt-in contacts.
- Double volume every 2 to 3 days while complaint and bounce rates stay clean.
- Prioritize recipients likely to reply or click; positive engagement accelerates trust.
- Monitor Postmaster Tools daily and pause the ramp if reputation drops.
- Reach target volume over 4 to 6 weeks for a cold domain; faster if you have an established parent domain.
Frequently asked questions#
How long does email warm-up take?
Two to six weeks depending on target volume and whether the domain is brand new.
Do I need to warm up a shared IP?
The IP is already warm, but your domain is not. Domain warm-up still applies.