The deliverability playbook

1. Authenticate everything

SPF, DKIM, DMARC are non-negotiable. Without all three set correctly, Gmail and Outlook treat your domain as suspicious by default. Sendlyst checks these continuously and alerts on drift.

2. Use a sending subdomain

Send from mail.yourdomain.com instead of yourdomain.com. This isolates your cold reputation from your transactional and marketing email. If cold goes badly, your invoices still deliver.

3. Warm up gradually

Brand-new mailboxes need 14-21 days of warmup. Start at 10-20 sends/day and ramp by 10-15% daily until you hit your target. Sendlyst's warmup network handles this automatically with thousands of real inboxes.

4. Watch your ratios

• Bounce rate < 3% — above this and providers start filtering
• Spam complaint rate < 0.1% — above this and you're throttled fast
• Reply rate > 2% — strong positive signal to inbox placement algorithms

5. Content matters

Avoid: link-heavy emails, images-only, "spam trigger" words, attachments, all-caps subject lines. Prefer: plain-text feel, conversational tone, one clear ask, signature with real identity.

6. Rotate mailboxes

One mailbox sending 500/day looks suspicious. Five mailboxes sending 100/day looks normal. Sendlyst rotates automatically.

7. Pause on signal

If bounce rate spikes or replies dry up, pause and diagnose. Don't push through — every bad week takes weeks to recover from.

8. Measure inbox placement directly

Don't trust delivered-rate (it's a lie). Use seed lists and real placement tests to know where your emails actually land. Sendlyst runs these weekly per mailbox.