How to warm up a new email domain
Mail providers decide where each email goes based on what they know about the sender. A new domain gives them nothing to go on, so warming builds that history before your first campaign.
Sent from a mailbox with no history, so the provider files it with the junk.
The same email, sent after the mailbox has built a reputation.
What providers look at
Authentication
SPF, DKIM and DMARC records prove an email really comes from your domain. Missing or broken records are one of the quickest ways into the spam folder.
DNS health checks every record on every domain and tells you exactly what to change when one drifts.
DNS healthSending history
Providers remember how much a domain and mailbox have sent, and for how long. A new mailbox that suddenly sends hundreds of emails looks like a spammer.
Warming raises volume a little each day. If you need to start sooner, aged domains and pre-warmed mailboxes come with history already.
Warming, pre-warmed mailboxesEngagement
Opens, replies and emails moved out of spam tell providers that people want your mail. Deletes without reading and silence suggest the opposite.
Warm-up emails are opened, replied to and rescued from spam, so your mailboxes build positive engagement before real prospects see them.
WarmingBounces and complaints
Emails to addresses that don't exist, and emails people report as spam, count heavily against you.
List check removes bad addresses before you send, and we slow a mailbox down automatically when bounces appear.
List check, automatic slow-downWarming up, step by step
- 01
Authenticate first
Set up SPF, DKIM and DMARC before the first warm-up email goes out. Check them with our free checker.
- 02
Start small
Begin with a handful of emails a day from each mailbox and raise the volume gradually. A sudden jump is what providers notice. Our standard schedule starts each mailbox at 3 emails a day and adds 3 a day, so it reaches 15 cold emails a day by day 5. The warm-up schedule calculator shows it day by day.
- 03
Earn real engagement
Warm-up emails should be opened, replied to and moved out of spam. That is the signal providers weigh most.
- 04
Watch for trouble
If bounces or spam placement appear, slow down until the mailbox recovers rather than pushing through.
- 05
Keep warming after launch
Leave warming running alongside your campaigns so reputation holds as volume grows.
What Gmail, Yahoo and Outlook now require.
Since 2024, Gmail and Yahoo have required bulk senders to meet a set of rules, and Microsoft introduced similar rules for Outlook in 2025. Gmail counts anyone sending close to 5,000 or more emails a day to personal Gmail accounts as a bulk sender, but the rules are good practice at any volume.
Set up, warm up and send from one app.
Delicious Mail handles every step on this page, from buying the domain to answering the reply.