The 2026 cold email deliverability checklist

Deliverability is infrastructure before it is copy. If authentication is misconfigured, the best-written sequence in the world lands in spam.

Start with SPF, DKIM and a DMARC policy that is at least p=quarantine. Then warm each sending identity gradually — a realistic curve is 10 to 20 sends per day in week one, doubling weekly while reply rates stay healthy.

Rotate senders so no single mailbox carries the whole campaign, insert randomised delays between sends, and rest the queue in batches. Nuvio Email Sender automates all three.

Finally, monitor. Track bounces, spam complaints and reply rate per sending identity, and pull any mailbox whose health degrades before it drags the domain down with it.