How to Check Your Email Sender Reputation (And Fix a Bad Score)
Your email sender reputation is the invisible score that determines whether your emails land in the inbox or in spam. Unlike a credit score, most people don't check it until something goes wrong. By then, the damage is already done. Here's how to check it and — if yours has taken a hit — how to repair it.
What Email Sender Reputation Is
ISPs (Google, Microsoft, Yahoo) maintain reputation scores for both IP addresses and domains. These scores influence inbox placement for every email you send.
Related guide: cold email deliverability tool
- Domain reputation is the more important metric for cold email. It's based on:
- Spam complaint rate from your domain's emails
- Bounce rate (hard bounces from invalid addresses)
- Engagement signals (open rates, reply rates, people moving your emails to inbox)
- Authentication status (SPF, DKIM, DMARC)
- Age and history of your domain
How to Check Your Sender Reputation
Google Postmaster Tools (postmaster.google.com): The most authoritative source for Gmail delivery. Shows your domain reputation (Good, Medium, Low, Bad), IP reputation, spam rate, and authentication compliance. Free to set up — add a TXT record to verify your domain.
Sender Score (senderscore.org): Scores IP reputation from 0-100. A score above 80 is healthy; below 70 means you likely have deliverability problems.
MXToolbox Blacklist Check (mxtoolbox.com/blacklists.aspx): Checks your domain and IP against 100+ email blacklists. If you're listed on a major blacklist (Spamhaus, Barracuda, SpamCop), it explains inbox placement problems immediately.
Related guide: cold email deliverability tool
Mail-Tester (mail-tester.com): Send a test email to a provided address and get an inbox placement score with specific recommendations. Useful for identifying content and configuration issues.
Signs Your Reputation Has Been Damaged
Sudden drop in open rates: If your open rate drops from 30%+ to under 10%, a significant portion of your emails are landing in spam. Increased bounce rate: More invalid email bounces than usual suggests your list quality dropped or your domain is being pre-filtered. Direct spam reports: If recipients tell you they found your email in spam, it's time to check your reputation. Postmaster Tools shows Medium or Low: Any rating below Good requires immediate attention.
How to Fix a Damaged Sender Reputation
Step 1: Stop sending cold email immediately. Continuing to send while your reputation is damaged compounds the problem. Pause campaigns completely.
Related guide: how to improve best cold email service
Step 2: Check and fix authentication. Verify SPF, DKIM, and DMARC are all configured correctly. Authentication failures are a common cause of reputation damage.
Step 3: Clean your email list. Remove any addresses that bounced, any spam complainants, and run your entire list through re-verification. Never send to the addresses that generated complaints.
Step 4: Request blacklist removal if needed. If you're on a major blacklist, follow the delisting instructions on that blacklist's website. Spamhaus and Barracuda both have self-service delisting for legitimate senders.
Related guide: cold email campaign software guide by SalesOutreach
Step 5: Rebuild with warm-up sending. Once your technical setup is clean and your list is verified, resume sending at very low volume (10-20/day) to highly engaged contacts. Build back positive engagement signals over 2-4 weeks before increasing volume.
Step 6: Monitor daily. While recovering, check Postmaster Tools every day. You're looking for domain reputation to move from Low/Medium back to Good.
Recovery timeline: Minor reputation damage from a brief spike in bounces typically recovers in 2-4 weeks with clean sending. Severe damage from extended high-spam-rate sending can take 2-3 months. A blacklisted domain that can't be delisted may need to be replaced with a new domain.
Prevention Is Far Easier Than Recovery
Once you've recovered, keep the reputation clean with three habits: verify every email before sending, never send to anyone who has complained, and monitor Postmaster Tools weekly. A 15-minute weekly check saves you weeks of recovery effort.