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Email Marketing Glossary.

Clear, no-fluff definitions of every email marketing term that matters—from open rates to double opt-in. 

 

Sending Domain

A sending domain is the domain your emails are sent from and authenticated against. Using your own custom sending domain—rather than a shared one—builds reputation and improves deliverability.

Also known as: custom domain, custom sending domain, from domain

Your sending domain is the identity behind every email you send. It's where authentication lives and where your reputation is built, which makes it foundational to reaching the inbox.

What is a custom sending domain?

A custom sending domain uses your own brand domain (yourbrand.com) to send email, rather than your provider's shared domain. It lets you authenticate with SPF, DKIM, and DMARC under your own name.

Why does the sending domain matter?

Reputation attaches to your domain. A custom, authenticated sending domain builds a reputation you control—improving deliverability and enabling standards like DMARC enforcement and BIMI.

Sending domain best practices

Authenticate it fully (SPF, DKIM, DMARC), warm it up if it's new, keep sending consistent, and align your visible from address with the authenticated domain.

Related terms

Sender Score IP Warming Dedicated IP Feedback Loop Email Authentication Blocklist BIMI Sender Reputation SPF DKIM DMARC Hard Bounce Soft Bounce Spam Trap Inbox Placement Mailbox Provider Email Deliverability

Related reading from Drip

Setting Up Custom Sending Domains (Help Center) Ecommerce Email Deliverability: 9 Ways to Reach the Inbox

Frequently asked questions

What is a sending domain?
A sending domain is the domain your emails are sent from and authenticated against. It's where SPF, DKIM, and DMARC records live and where your sender reputation is built.
What is a custom sending domain?
A custom sending domain uses your own brand domain to send email instead of your provider's shared domain, letting you authenticate under your own name and build a reputation you control.
Why does the sending domain matter for deliverability?
Sender reputation attaches to the sending domain. A custom, authenticated domain gives you a reputation you own, improves inbox placement, and enables standards like DMARC enforcement and BIMI.
Should I use a custom sending domain?
For most serious senders, yes. A custom, authenticated sending domain builds domain reputation you control and improves deliverability. New domains should be warmed up gradually before sending at full volume.
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