Cold email that reaches the inbox: the five things that actually matter

Most people blame the copy. Usually the copy was fine; the mail never arrived.

1. Authentication before anything else

SPF tells the receiving server which IPs may send for your domain. DKIM signs the message so it cannot be altered in transit. DMARC tells the receiver what to do when either check fails. Publish all three before your first campaign — Gmail and Outlook increasingly treat a missing DMARC record as a reason to filter you into promotions or spam.

2. Warm-up is not optional

A brand-new IP has no reputation, and volume spikes look exactly like a compromised machine. Start at a few hundred a day, increase by roughly 20–30% a day, and watch the bounce and complaint rate before each increase. Two weeks of boring ramping buys you months of reliable delivery.

3. Bounces are a data problem

Anything above 2% hard bounces means the list is wrong, not that the sending is wrong. Verify addresses with an SMTP probe before they enter the list, remove hard bounces immediately, and treat catch-all domains as a separate, lower-trust segment.

4. One domain for mail, one for the site

If your cold outreach damages your main domain's reputation, your transactional email and password resets suffer too. Send campaigns from a separate subdomain, and keep the reply-to on a mailbox you actually read.

5. Write like a person, send like a system

Short plain-text messages with one question outperform polished HTML templates for first contact. Then let the system handle the schedule: consistent daily volume, no bursts, and a stop rule the moment someone replies.

BuddyMail ships the records, the warm-up scheduler, the bounce parsing and the stop rules — self-hosted, so the reputation you build belongs to your own domain.