Warm-up builds your mailbox's sending reputation by exchanging genuine-looking emails that get opened and replied to. A new or cold mailbox that starts blasting campaigns will land in spam — warm-up prevents that.
Turn on warm-up
Go to Email Accounts in the left sidebar.
Open the account you want to warm up.
Go to the Warmup tab.
Enable warm-up and configure the settings below.
Warm-up settings
Setting | Suggested value | What it does |
Daily Warmup Limit | 10 | How many warm-up emails this mailbox sends per day |
Increase Per Day | 1 | How much the daily volume grows each day |
Disable slow warmups | Off | Turn on to skip the gradual ramp-up |
Reply Rate % | 30 | What share of warm-up emails receive a reply |
Weekdays Only | On | Restricts warm-up to weekdays, mirroring real sending behaviour |
Read Emulation | On | Simulates a human reading the email before replying |
Open Rate % | — | Target open rate for warm-up emails |
Spam Protection % | — | How often warm-up emails are rescued from the spam folder |
Mark Important % | — | How often warm-up emails are marked as important |
Start conservative. A daily limit of 10 with an increase of 1 per day is a safe default for a brand-new mailbox.
Monitoring your account health
Each connected account shows a health score from 0 to 100, colour-coded:
Green (80+) — healthy, safe to send
Yellow (50-79) — needs attention; slow down and let warm-up continue
Red (below 50) — do not run campaigns from this mailbox until it recovers
You'll also see Sent as a daily usage figure against that account's daily limit.
How long to warm up
Run warm-up for at least 2-3 weeks on a brand-new mailbox before sending campaigns, and keep warm-up running permanently alongside your campaigns. It isn't a one-off setup step — it's ongoing reputation maintenance.
Best practices
Warm up every mailbox you plan to send from, not just the first one.
Don't raise your campaign volume the moment warm-up starts. Let the health score climb first.
If your health score drops, pause campaigns from that mailbox and let warm-up run on its own for a few days.