The short version
Deliverability is a reputation system. You earn inbox placement with authenticated domains, moderate steady volume, real replies, and low complaint rates. You lose it with bursts, bounces, and spammy copy.
Foundation
- Authenticate — SPF and DKIM set up correctly. See SPF and DKIM authentication.
- Warm up gradually — start new mailboxes at low volume and ramp.
- Set sane limits — Daily Sending Limit per mailbox, Daily Prospect Start per campaign.
- Use sending windows — spread sends across business hours instead of dumping at 9:00:00.
List hygiene
- Never buy lists of unknown quality — unknown recipients bounce and mark you as spam.
- Remove hard bounces promptly; monitor the Bounced filter in Prospects.
- Honor opt-outs — PersistIQ does this automatically, don't override it manually.
Content
- One link maximum in cold emails; no link shorteners.
- Minimal images and no attachments on first touch.
- Pass the SEVEN SECOND TEST — long, image-heavy emails read as marketing blasts.
Monitor
Watch open and reply rates in Reporting. A sudden open-rate drop across the board is usually a deliverability event, not a copy problem — pause, diagnose, resume. See Why campaigns pause in Troubleshooting.