The inbox is the real funnel

The best-written sequence is worthless in the spam folder. Deliverability is the unglamorous foundation under every outreach number, and most teams ignore it until their reply rate quietly collapses.

Authenticate everything

Three records, non-negotiable:

  • SPF — authorizes which servers can send for your domain.
  • DKIM — cryptographically signs your mail so receivers can verify it.
  • DMARC — tells receivers what to do with mail that fails the above. Start at p=none to monitor, then tighten.

Without all three aligned, Gmail and Outlook increasingly route you straight to spam.

Warm up new domains

Never blast a fresh sending domain. Ramp volume over 3–4 weeks, starting at a few dozen sends a day. Better: send outreach from a separate domain (e.g. get.yourcompany.com) so a reputation hit never touches your primary email.

Protect your reputation daily

  1. Verify lists before sending. Bounces above 3% signal spam systems. Run every list through validation.
  2. Watch the spam-complaint rate. Above 0.1% and mailbox providers throttle you.
  3. Remove non-responders. Mailing people who never open trains filters to distrust you.

Content signals matter too

  • Avoid spammy phrasing ("free," "act now," "guaranteed").
  • Keep the link-to-text ratio low — one link, maybe two.
  • Plain-text or lightly-formatted emails outperform heavy HTML templates for 1:1 outreach.

Measure the right number

Open rates are now unreliable thanks to privacy proxies. Track reply rate and bounce rate as your deliverability dashboard. A reply rate that drops while sends stay constant is your early warning that you're sliding toward spam.