List hygiene is the ongoing removal of invalid, inactive, and risky addresses from a mailing list, plus verification of new addresses at the point of capture.
What is a spam trap?
An address that never opted in, maintained by providers and blocklists to catch senders with poor acquisition practices. Hitting one can blocklist your IP or domain.
What bounce rate is acceptable?
Under 2% hard bounces. Above 5% typically triggers ESP account reviews.
Why does email list hygiene matter for deliverability?
Bounces, spam traps, and disengaged recipients are the three fastest ways to damage reputation, and all three are prevented by hygiene.
What is the first step to get started with email list hygiene?
Verify new signups in real time with an API and use double opt-in for marketing lists.
What is the most common email list hygiene mistake?
Importing old exports without verification.