Sender Score

What is Sender Score?

Sender Score is a 0-100 rating that evaluates the reputation of your email sending IP address or domain, similar to a credit score for email senders. Developed by Return Path (now Validity), it's one of the most widely recognized email reputation metrics.

Score Interpretation:

A sender score below 70 means your emails are likely being filtered to spam folders or blocked entirely.

Why Sender Score Matters

Inbox Placement:
Email providers use sender reputation as a primary filtering signal. Low scores directly cause emails to bypass the inbox.

Sending Limits:
Some providers throttle or block senders with poor scores. You may be limited to sending a few emails per day regardless of your infrastructure.

Domain Warming:
New domains start with no reputation. Building to a score of 90+ takes 2-4 weeks of proper warm-up and consistent sending practices.

Competitive Advantage:
High sender scores ensure your outreach actually reaches prospects while competitors with poor scores waste money on emails that never get seen.

How Sender Score Is Calculated

Sender Score algorithms consider multiple factors:

Engagement Metrics (40% weight):

• Open rates
• Click-through rates
• Reply rates
• Delete-without-reading rates
• "This is not spam" complaints

• Spam button clicks
• Abuse reports
• ISP feedback loop submissions

• SPF, DKIM, DMARC authentication
• Sending infrastructure quality
• IP/domain relationship

• Sending patterns
• Volume spikes
• List hygiene practices

Improving Your Sender Score

1. Proper Authentication

Required Setup:

SPF records: Authorize sending IPs
 DKIM signatures: Prove message authenticity
 DMARC policy: Tell servers how to handle failures

2. List Hygiene

Regular Cleaning:

• Remove hard bounces immediately
• Process unsubscribe requests instantly
• Remove inactive subscribers (no opens in 6+ months)
• Never purchase or rent email lists

3. Engagement Focus

Best Practices:

• Send content recipients actually want
• Segment by engagement level
• Re-engagement campaigns before removing inactive subscribers
• Monitor and minimize complaints

4. Consistent Sending Patterns

Recommended Approach:

• Gradually increase volume during warm-up
• Maintain consistent daily/weekly sending
• Avoid sudden volume spikes
• Send during business hours in recipient timezones

5. Monitor and Respond

Key Metrics to Track:

• Complaint rate (should be <0.1%)
• Bounce rate (should be <2%)
• Unsubscribe rate (should be <0.5%)
• Spam trap hits (should be zero)

Checking Your Sender Score

Free Tools:

• SenderScore.org – Free lookup by IP address
• MXToolbox – Blacklist and reputation checking
• [Google Postmaster Tools] – For Gmail senders only

• Validity – Comprehensive deliverability suite
• 250ok – Email analytics and monitoring
• NeverBounce – List cleaning with reputation insights

Common Sender Score Issues

Volume Spikes

Problem: Sudden increase in sending volume triggers spam filters.

Solution: Gradual ramp-up over 2-4 weeks during warm-up.

Spam Trap Hits

Problem: Emailing spam traps destroys reputation instantly.

Solution: Never buy lists, regularly clean your database, use confirmed opt-in.

High Complaint Rates

Problem: Recipients marking messages as spam.

Solution: Better targeting, clearer opt-in process, easier unsubscribe.

Poor Authentication

Problem: Missing SPF/DKIM/DMARC records.

Solution: Complete authentication setup immediately.

Recovery from Low Sender Scores

If Your Score Drops Below 70:

1. Immediate Action:
- Stop all email marketing immediately
- Identify the cause (complaints, bounces, spam traps)
- Remove problematic addresses

2. Infrastructure Review:
- Verify SPF/DKIM/DMARC setup
- Check for compromised accounts
- Audit all sending sources

3. Rebuild Strategy:
- Start fresh with new sending domain if severely damaged
- Re-warm gradually with engaged subscribers only
- Monitor scores daily during recovery period

4. Prevent Recurrence:
- Implement double opt-in
- Regular list cleaning
- Engagement-based segmentation

Key Takeaways

• Sender Score is 0-100 reputation rating for email senders
• 90+ is excellent; below 70 causes major deliverability problems
• Based on engagement, complaints, infrastructure, and sending patterns
• Improve through: authentication, list hygiene, engagement focus
• Check scores at SenderScore.org and other free tools
• Common issues: volume spikes, spam traps, high complaints
• Recovery requires stopping sends, fixing causes, and re-warming
• Monitor score regularly as part of email marketing operations