Deliverability without burning your main domain

TL;DR Never cold send from your primary domain. Warm secondary domains for two to three weeks before real volume. Replace burned inboxes — do not patch and pray.

Your main domain carries your entire business email reputation. Cold outbound on it is how teams accidentally blacklist their own customer-facing inbox.

Secondary domains on private infrastructure, warmed before send, are the baseline — not an advanced tactic.

Volume must be distributed across inboxes. One inbox sending hundreds of emails daily is a fast path to spam folders.

If a domain burns, replace and re-warm. The cost of replacement is cheaper than recovering a blacklisted primary domain.