Deliverability is not a switch you flip at launch. It is the sum of authentication, list quality, engagement, and how you react to bounces.
- Authenticate everything — SPF, DKIM, and a published DMARC policy (start with
p=none, move toward quarantine). - Warm up gradually — new domains and IPs should ramp volume over days, not hours.
- Never purchase lists — imported cold contacts destroy reputation fast.
- Suppress hard bounces immediately — sending again to dead addresses signals poor hygiene.
- Monitor complaint rates — feedback loops and “Mark as spam” rates should stay well below provider thresholds.
- Match From domains to links — alignment between envelope, header From, and click domains helps trust.
- Plain-text alternative — include a text part for multipart messages.
- Stable sending patterns — sudden 10× spikes without warming look like compromise.
- Readable subjects — avoid ALL CAPS, deceptive subjects, and URL shorteners in auth mail.
- Instrument every send — if you cannot see SMTP responses and bounce codes, you cannot fix problems.
Mailmatic stores delivery events and classifies bounces so suppressed addresses do not get hammered on the next campaign.