Deliverability is the topic most people tackle when the open rate has dropped to 8% and nobody knows why. This guide is the order to tackle it before that: domain, DNS, warm-up, volume, content, signals.
Every step has a screen in Colldly that tells you whether it is done. None of it is one-off: deliverability is monitored continuously, not set once.
Separate your outreach domain
Never send campaigns from the domain you use to communicate with clients. Buy a similar domain and use it only for outreach. If its reputation suffers, your main mail stays untouched.
Set up all three DNS records
SPF says who may send on behalf of your domain. DKIM signs messages so their authenticity can be verified. DMARC decides what to do with a message that fails the checks. Without DMARC the big providers gradually penalise you.
Warm up for two to four weeks
A new mailbox needs a history of ordinary communication. Warm-up sends small volumes, receives replies and gradually raises the cap. It pulls messages out of spam into the inbox itself, repairing reputation.
Keep a safe daily volume
For a warmed-up mailbox count on up to 50 cold emails a day. Want more? Add mailboxes, not volume on one. Ten mailboxes at 40 emails each are safer than two at 200.
Clean the list before sending
Keep the bounce rate under 3%. Address verification runs automatically, but consider dropping risky and catch-all addresses if your bounces grow. One badly cleaned batch can ruin weeks of warm-up.
Watch the signals and react
When bounces rise or the open rate drops, stop and look for the cause before sending another thousand. The system sends you an alert, but the decision is yours.
Write so the filters let you through
No attachments, minimal links, no image footers, no words like "free" in the subject. Plain text from a human always passes better than a graphically polished email.
- Cold emails go out from a secondary domain, not your main one
- SPF, DKIM and DMARC passed the check under Deliverability
- A new mailbox warmed up for 14 to 28 days
- Daily limit per mailbox is under 50, gaps are random
- Bounce rate is under 3%, hard bounces are removed
- Emails are plain text, no images, at most one link and only in a follow-up
- You have a custom tracking domain