A customer places an order. They wait for the confirmation email. It never arrives.
The system didn't fail. The email was sent. But somewhere between your servers and their inbox, it got caught in the crossfire of a marketing campaign that went sideways. Too many bounces, too many unsubscribes, and suddenly your domain reputation took a hit. The order confirmation landed in spam, right next to the promotional email that caused the problem.
This is what happens when marketing, transactional, and service emails share a single branded sending domain. One bad campaign can drag down deliverability for every message you send.
One domain, one problem: why shared sending domains put critical emails at risk
Email deliverability isn't just about what you send. It's about the reputation of the domain sending it. When all your email flows through one branded sending domain, inbox providers see it as a single entity. High bounce rates on a promotional blast? That reputation damage carries over to your password reset emails. Low engagement on a re-engagement campaign? Your order confirmations suffer the consequences.
The emails most affected are the ones customers can't afford to miss:
- Order confirmations prove a purchase went through
- Shipping updates set delivery expectations
- Password resets get customers back into their accounts
- Customer service replies resolve open issues
When these messages land in spam, or don't arrive at all, customers lose trust. They contact support. They dispute charges. They leave.
The transactional and service emails themselves did nothing wrong. They just happened to share a domain with marketing volume that moves the reputation needle in unpredictable ways.
What's new: dedicated branded sending domains for marketing, transactional, and service email
That changes now. Klaviyo customers can configure separate branded sending domains for each email type: marketing, transactional, and service.
This is generally available to all customer segments across all regions. If you use Klaviyo Email, you can split your marketing and transactional sends onto different domains. If you use Helpdesk, you can now use a branded sending domain on your service emails for the first time.
No more single point of failure. No more marketing campaigns putting order confirmations at risk.
How separate sending domains protect your deliverability
Reputation isolation is the core benefit. When each email type has its own domain, the reputation of one doesn't affect the others.
Here's what that looks like in practice:
A promotional campaign goes out to a large segment. Some addresses bounce. Some recipients unsubscribe. The marketing domain's reputation takes a temporary dip. But your transactional domain? Untouched. Password resets still land in primary inboxes. Order confirmations still arrive instantly.
For Helpdesk users, this also means service emails finally look the way they should. Instead of sending support replies from a generic domain, you can use your brand's domain. You build trust with customers at the exact moment they need reassurance that they're talking to the real you.
This change also lays groundwork for future improvements. Splitting domains prepares your account for infrastructure upgrades, including migration from legacy email providers to Klaviyo's own mail transfer agent.
When to use each domain type
Not sure which emails belong on which domain? Here's a simple breakdown:
Marketing domain: Promotional campaigns, newsletters, product announcements, browse abandonment flows, win-back sequences. Anything designed to drive engagement or sales. These emails are valuable, but recipients can live without them.
Transactional domain: Order confirmations, shipping notifications, password resets, account alerts, subscription renewals. These are messages the customer explicitly expects as a result of an action they took. Missing one creates a real problem.
Service domain: Helpdesk replies, support ticket updates, customer service follow-ups. These are direct responses to customer inquiries. Conversations, not broadcasts.
The decision heuristic is simple: if the customer would be upset not to receive the email, it belongs on your transactional or service domain. If it's a nice-to-have, it stays on marketing.
How to configure your branded sending domains
Setting up separate domains happens in your Klaviyo account settings. The process involves adding DNS records for each domain type you want to use, similar to how you configured your original branded sending domain.
For detailed setup instructions, including the specific DNS records required, see the branded sending domains help documentation.
If you already have a branded sending domain configured, you can add additional domains without disrupting your current sends. Your existing setup continues working while you configure and verify new domains.
Before you start, take a few minutes to audit your current email sends. Which flows and campaigns are truly transactional? Which Helpdesk replies could benefit from branded sending? Mapping your emails to the right domain type upfront makes configuration straightforward.
Get started
Shared sending domains create shared risk. When marketing reputation dips, transactional and service emails pay the price.
Separate branded sending domains fix that. Your order confirmations stay protected. Your password resets land on time. Your support replies look professional and trustworthy.
If you're using Helpdesk, this is your chance to add branded sending on service email for the first time. Your customers will notice the difference.