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Choosing a sending domain

Why a dedicated subdomain like notify.acme.com is the right home for your transactional email.

Overview

Section titled “Overview”

Your sending domain is the domain your live emails come from — the part after the @ in every From address. Base includes one sending domain. Transactional Email strongly recommends a subdomain used only for transactional email, such as notify.acme.com or mail.acme.com. You can use your root domain (acme.com), but Settings warns you first.

Why a subdomain

Section titled “Why a subdomain”
  • Separate reputation. Mailbox providers like Gmail and Outlook track reputation per domain and subdomain. A dedicated subdomain keeps your receipts and account notices apart from your corporate and marketing email, so a marketing campaign that draws complaints can’t drag down your receipts — and the other way round.
  • No DMARC conflicts. If your root domain has a strict DMARC policy, a subdomain avoids clashing with it.
  • Tidy DNS. All the records Transactional Email needs live under one name, so they’re easy to find and never collide with your existing mail setup.

Good choices

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Domain Verdict
notify.acme.com, mail.acme.com, billing.acme.com Recommended: a subdomain of the domain your customers know.
acme.com Allowed, with a warning. Shares reputation with all your other mail.
acme-notifications.com Avoid: a domain recipients don’t recognize can look like phishing.

Pick a domain you’ll keep. Your From addresses must use exactly this domain — with notify.acme.com, that’s billing@notify.acme.com, not billing@acme.com — and replies can still go anywhere you like through the sender profile’s reply-to.

Before you commit

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  • You need access to the domain’s DNS, or someone who has it. Settings can email the records to your IT team.
  • Changing domains later restarts warm-up. Base includes one domain, so switching means removing the current one and adding the new one. Sends fail with sender_invalid until the new domain verifies, and the daily limits start again from day 1. See How warm-up works.
  • Sender profiles follow the domain. A profile stores only the part before the @, so after a switch it sends from the same name on the new domain.
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