Sender reputation

Sender reputation is the score, or set of scores, a mailbox provider keeps about you. Providers don't publish exact formulas, but the inputs are well understood: the reputation of your sending IP addresses, the reputation of your domains (domain reputation), spam complaints, bounces, hits on spam traps, listings on blocklists, authentication results, sending consistency and how recipients engage (opens, replies, moving mail out of spam).

Reputation is built per provider and over time. A new IP or domain has little history, which is why warm-up exists, and a burst of bad sends can undo months of good behaviour.

Your reputation decides whether good emails reach the inbox. On shared sending infrastructure, your reputation also depends partly on other senders, which is why outreach teams often use dedicated domains and keep tight control of list quality. Google publishes requirements on spam rate, authentication and sending patterns that feed this assessment.

Bounces are one of the reputation inputs you fully control. Verify every list with Skrap.ai first, using the free email verifier, a bulk CSV upload or the Google Sheets add-on. Then use the email finder, which only returns emails it has verified.