What is the risk of using your main domain for cold campaigns?

Your main domain sends all your critical email: password resets, order confirmations, support replies, and marketing to opted-in subscribers. Domain reputation affects all of it.

Cold outreach risks:

Reputation damage: Higher complaint rates from cold campaigns can lower your domain's reputation score. Once damaged, all email from that domain suffers, including transactional messages your customers depend on.

Blocklisting: Getting your main domain blocklisted affects your entire email program. Delisting takes time and isn't always successful.

Deliverability decline: Even without blocklisting, accumulated negative signals push more of your mail to spam folders across all categories.

Brand damage: Recipients who receive unwanted cold email associate that experience with your brand directly.

Many organizations isolate cold outreach on separate domains specifically to protect their main domain. The cost of registering additional domains is trivial compared to the risk of compromising your primary email infrastructure.