You can write the best cold email in the world, and it will produce exactly zero meetings if it lands in spam. Deliverability is the unglamorous foundation every outbound program is built on — and the first thing most teams get wrong.
Protect your primary domain
Never send cold volume from your primary domain. Register dedicated sending domains, configure SPF, DKIM, and DMARC correctly, and treat each mailbox as a limited, warm resource rather than a firehose.
Warm up, then ramp slowly
- Warm each mailbox for 2–4 weeks before real sends.
- Cap daily volume per mailbox — think dozens, not hundreds.
- Ramp gradually; sudden spikes look like exactly what spam filters hunt for.
The signals providers watch
Inbox providers infer intent from behavior. Positive replies, opens from engaged recipients, and low bounce rates build reputation. Spam complaints, hard bounces to bad data, and identical templates sent at scale destroy it. Clean your lists, verify addresses, and keep messages varied and genuinely relevant.
“Deliverability is a reputation game. Every send either earns trust with the inbox or spends it — send like you intend to be there next quarter.”
Measure placement, not just opens
Open tracking is increasingly unreliable. Monitor inbox placement directly with seed tests, watch reply rates as the real signal of health, and pause any mailbox whose numbers slip before it drags the rest down.
