Cold email deliverability: the SPF, DKIM & DMARC setup that lands

The best copy in the world can't book a meeting from the spam folder. Deliverability is the unglamorous foundation that decides whether your campaign exists. Here's the setup that keeps you landing.

Authenticate everything: SPF, DKIM, DMARC

These three records prove to inbox providers that your mail is really from you. SPF authorises your sending servers, DKIM cryptographically signs each message, and DMARC tells receivers what to do if a message fails. Missing any of them is an instant credibility hit with Gmail and Outlook.

Separate domains, never your main one

Send cold email from dedicated lookalike domains, never your primary company domain. If a sending domain's reputation gets damaged, you want it to be a throwaway, not the address your customers email.

Warm up before you scale

New inboxes have no reputation. Ramp sending volume gradually over weeks, with warmup tools generating natural-looking engagement, before you send a single real campaign. Skipping this is the most common reason new domains die.

Then keep it healthy

Cap volume per inbox, rotate senders, prune invalid addresses, and watch your bounce and spam-complaint rates daily. Deliverability isn't a one-time setup, it's an ongoing discipline.

Inbox placement is earned, not configured once. Treat sender reputation like the asset it is.