Sending & Deliverability
IP Warmup Schedule for New Sending Servers
Why Warm Up?
New IPs have zero reputation. If you send thousands of emails immediately, ISPs will flag you as a potential spammer. Warming up gradually builds trust.
Recommended Schedule
| Week | Day | Daily Volume | Cumulative | Notes |
|---|---|---|---|---|
| 1 | 1-2 | 50 | 100 | Most engaged subscribers only |
| 1 | 3-4 | 100 | 300 | Monitor for bounces |
| 1 | 5-7 | 250 | 1,050 | Check inbox placement |
| 2 | 8-10 | 500 | 2,550 | Review reputation dashboards |
| 2 | 11-14 | 1,000 | 6,550 | |
| 3 | 15-18 | 2,500 | 16,550 | |
| 3 | 19-21 | 5,000 | 31,550 | Google Postmaster check |
| 4 | 22-25 | 10,000 | 71,550 | |
| 4 | 26-28 | 25,000 | 146,550 | |
| 5 | 29-35 | 50,000 | 496,550 | |
| 6+ | 36+ | Full volume | - | Maintain consistency |
AcelleMail Configuration
Set per-server sending limits to enforce the warmup schedule:
Admin → Sending Servers → Edit → Sending Limit
Day 1-2: 50 emails per day
Day 3-4: 100 emails per day
...adjust weekly
Monitoring During Warmup
Key Metrics to Watch
- Bounce rate: Must stay below 2%
- Complaint rate: Must stay below 0.1%
- Inbox placement: Use Google Postmaster Tools
Red Flags (Stop and Investigate)
- Bounce rate exceeds 5%
- Complaint rate exceeds 0.3%
- Emails deferred by major ISPs (Gmail, Yahoo)
- IP listed on any blacklist (check mxtoolbox.com)
Tools for Monitoring
# Check blacklists
curl -s "https://mxtoolbox.com/api/v1/Lookup/blacklist/?argument=YOUR_IP"
# Check Google Postmaster Tools
# → https://postmaster.google.com/
Tips for Success
- Start with your best subscribers — recent openers and clickers
- Send consistently — don't skip days during warmup
- Separate by ISP — warm up Gmail, Yahoo, Outlook independently if possible
- Use authentication — SPF, DKIM, DMARC must be configured before warmup
- Avoid purchased lists — only send to confirmed opt-in subscribers