IP reputation is the trust score that mailbox providers (Gmail, Yahoo, Outlook, Apple Mail) assign to the IP address that delivers your emails. The higher the score, the more likely your messages reach the inbox. A bad reputation means your campaigns land in spam — or are blocked entirely.
How IP reputation is calculated
Each ISP keeps a private score per IP. Public services such as Sender Score, Talos, ReturnPath and SpamHaus aggregate similar signals into a 0–100 number. Key inputs include:
- Volume and consistency of sending
- Spam complaint rate (target: < 0.1%)
- Hard bounce rate (target: < 2%)
- Spam-trap hits (must be 0)
- Authentication (SPF, DKIM, DMARC) results
- Engagement: opens, clicks, replies vs deletes
How the score affects delivery
| Sender Score | Inbox placement | Action |
|---|---|---|
| 90–100 | Excellent — consistently in inbox | Maintain habits |
| 80–89 | Good — occasional spam folder | Improve engagement |
| 70–79 | At risk — throttling likely | Audit list quality |
| Below 70 | Poor — mostly spam or blocked | Rebuild reputation |
Shared vs dedicated IP
On a shared IP, you inherit the reputation of dozens of senders — pooled, often stable, but you depend on others. On a dedicated IP, you control the score entirely — better for high volume (50,000+ emails/month) but you must warm it up over weeks.
How to protect (and improve) your IP reputation
1. Send only to opt-in subscribers — ideally double opt-in. 2. Configure SPF, DKIM and DMARC. 3. Clean your list regularly: remove hard bounces and inactive subscribers. 4. Send relevant content: better engagement = better score. 5. Avoid spam-trigger words and image-only emails. 6. Maintain a steady sending volume; sudden spikes are suspicious.
Mailpro’s approach
Mailpro actively monitors the reputation of every sending IP, removes problematic accounts and provides automatic warm-up plans for dedicated IPs. Read more in our IP reputation blog post and how IP reputation affects delivery.
Send from trusted IPs by default
Mailpro’s IP reputation management keeps your shared IP clean, with active monitoring, abuse handling and the option to upgrade to a dedicated IP. See the deliverability page for more.