Every new mailbox starts with zero reputation. To Gmail and Outlook, unknown + sudden volume = spammer. Warm-up is the process of earning trust slowly, and skipping it is the number one reason cold campaigns die in spam.
Why warm-up works
Filters watch volume trends, bounce and complaint rates, and — critically — engagement: do your sent emails get opened, replied to, marked "not spam" and removed from junk? Warm-up generates this positive signal with realistic back-and-forth traffic.
A realistic 30-day ramp (per mailbox)
- Week 1: 10–15/day, mostly warm conversations, a handful of outreach.
- Week 2: 20–25/day with genuine replies.
- Week 3: 30–40/day, begin light campaigns.
- Week 4+: up to 40–60/day sustained; keep background warm traffic running.
What good warm-up includes
- Both sending and receiving, with human-length reply threads.
- Messages opened, then occasionally dragged out of spam and marked important.
- Gradual, randomized volume — never a flat robot curve.
- Content variety instead of one repeated template.
Mistakes that undo warm-up
- Going too fast: jumping from 10 to 200/day in a weekend.
- Sending-only: no inbound engagement means a one-sided, spam-like graph.
- Stopping cold: reputation decays; keep low warm traffic during pauses.
- Ignoring authentication: warm-up cannot rescue missing SPF/DKIM/DMARC.
- Blasting a bought list: hard bounces and spam traps destroy a fresh domain in hours.
How AutoAiMail handles it
Connect a mailbox and warm-up starts automatically on the schedule above, with randomized realistic conversations, volume that ramps per provider limits, and a live reputation score. When you launch a campaign, sending is throttled against the warmed capacity so you never outrun your reputation.