Skip to content
KlosyKlosent

Protect email deliverability before scaling

Last verified 2026-08-18

  • Set up SPF, DKIM, and DMARC correctly for every sending domain. Google requires SPF or DKIM for all senders and all three for senders above its 5,000-message daily threshold; Yahoo and Microsoft publish similar high-volume requirements.
  • Align the visible From domain with SPF or DKIM, use TLS, and keep valid forward and reverse DNS where your sending setup controls them.
  • Verify addresses and suppress known bad or opted-out contacts before sending.
  • Increase volume gradually. Sudden spikes are a risk even when a tool allows them.
  • Keep sender identity, headers, and subjects accurate. Do not imitate a reply or forward when the message is not one.
  • Make opt-out simple. High-volume marketing messages to personal Gmail accounts require one-click unsubscribe plus a visible unsubscribe link.
  • Watch bounces, provider errors, replies, and account health. Pause and investigate a bad pattern instead of pushing through it.
Google says to keep reported spam below 0.3% and recommends staying below 0.1%. Treat those figures as warning boundaries, not targets. Provider rules can change, so check the primary-source links before a major volume change.
No warm-up tool or setting guarantees inbox placement. Healthy delivery comes from correct setup, good data, wanted messages, and conservative sending behavior together.

Primary sources

These links were reviewed to prepare this guide. Provider policies and laws can change.

Was this helpful?

Still stuck? hello@klosent.com. A human reads every message.