Workflow
Controlling bounce rate in cold email
Most avoidable bounces come from the list, not the message. Verify first, send in stages, and use the first batch as a check.
Before sending
Verify the list and remove invalid and disposable. Hold catchall for a small test. Many senders aim to keep hard bounces to a low single-digit percentage; check the limits your platform and mailbox provider publish.
While sending
Send a first batch of a few dozen, check bounces, then scale. If bounces rise, pause, re-verify the remaining list and look for a segment that caused it.
After sending
Suppress every bounced address everywhere so it is never sent to again, and record which source produced the bounces.