Sender reputation

Also called: Domain reputation, IP reputation.

Gmail, Yahoo and Outlook each keep their own view of how trustworthy your mail is. They don't publish the formula, but their guidelines show the inputs: spam complaints, attempts to deliver to invalid addresses, authentication (SPF, DKIM, DMARC), sending patterns, spam-trap hits and how recipients engage.

The clearest published number is the complaint threshold. Google asks senders to keep the spam rate in Postmaster Tools below 0.1% and never let it reach 0.3%; Yahoo asks bulk senders to stay below 0.3%. Bounces count too: Amazon SES notes that providers read a high bounce rate as a sign a sender isn't managing their list.

Reputation is mostly tied to your domain now, which is why cold emailers send from a separate domain: if it gets damaged, your main domain's mail to clients keeps working. Rebuilding a damaged reputation takes weeks of low, clean volume.

In local lead generation, the biggest threats are lists with unverified or guessed addresses, catch-all domains mixed into verified sends, and messages that aren't relevant to the business. Clean lists and relevant messages protect reputation better than any tool.

Example

A new domain sends 2,000 emails on day one to an unverified list. Bounces and complaints spike, and later mail from the domain starts landing in spam even for verified addresses.