Email Blacklists 101: How to Stay Off Them
Find out why domains get blacklisted and actionable tips to maintain a clean sender reputation.
What are Blacklists?
Blacklists (Real-time Blackhole Lists or RBLs) are databases of IP addresses and domains suspected of sending spam. If your IP ends up on a major list (like Spamhaus or Barracuda), your delivery rates will plummet.
Common Causes of Blacklisting
- Spam Traps: Sending to old, dormant email addresses used by providers to catch spammers.
- High Bounce Rates: Sending to too many invalid email addresses signals poor data quality.
- Compromised Accounts: If a user's password is stolen, their account might be used to blast spam.
Stay Clean: The best way to avoid blacklists is to never send to unverified addresses. Run your lists through our Bulk Email Checker every 3 months.
Related Articles
The Impact of Invalid Emails on Deliverability
Why cleaning your email list is not just about saving money—it's about saving your domain reputation.
Soft Bounce vs Hard Bounce: What's the Difference?
Understanding email bounce codes and when to remove a subscriber from your list.