Sender Reputation
A score assigned by ISPs to your email sending domain/IP that determines whether your emails reach the inbox.
Sender reputation is a trust score that Internet Service Providers (ISPs) like Gmail, Microsoft, and Yahoo assign to your sending domain and IP address. A high reputation means your emails land in the inbox; a low reputation means they go to spam or get blocked entirely.
Factors that affect sender reputation:
- Bounce rate: High bounces signal a dirty list
- Spam complaints: Recipients marking your email as spam
- Engagement: Open rates, click rates, and reply rates
- Sending volume consistency: Sudden spikes look suspicious
- Authentication: Proper SPF, DKIM, and DMARC configuration
- Blacklist presence: Being listed on RBLs (Real-time Blackhole Lists)
How to check your reputation:
- Google Postmaster Tools (for Gmail delivery)
- Microsoft SNDS (for Outlook/Hotmail)
- Sender Score by Validity
- SendSure's Deliverability Testing tool
Email verification's role: Regular email verification is one of the most effective ways to protect sender reputation by removing invalid, risky, and disposable addresses before they generate bounces.
Related Terms
Bounce Rate
The percentage of emails that could not be delivered to the recipient's inbox.
SPF (Sender Policy Framework)
A DNS record that specifies which mail servers are authorized to send email on behalf of your domain.
DKIM (DomainKeys Identified Mail)
A cryptographic email authentication method that verifies an email was sent by an authorized server and wasn't altered in transit.
DMARC (Domain-based Message Authentication)
A protocol that tells receiving servers what to do when SPF or DKIM checks fail for your domain.
Email Blacklist (RBL)
A database of IP addresses and domains known to send spam, used by ISPs to filter incoming email.
Related Blog Posts
Want to learn more?
Read our in-depth blog posts on email verification and deliverability.