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TL;DR: A Klaviyo sender domain setup routes your emails through your own branded subdomain instead of Klaviyo's shared one, which protects your sender reputation and helps you land in the inbox. You add a few DNS records, verify them in Klaviyo, then warm the domain if it's new. Bulk senders now need one to meet Gmail and Yahoo rules. Here's the full walkthrough.
A Klaviyo sender domain setup is the process of authenticating a branded subdomain so your Shopify store sends email from your own domain instead of Klaviyo's shared one. It's one of the highest-leverage deliverability moves you can make, and it takes about 20 minutes of real work. The rest is waiting on DNS.
Most stores start on Klaviyo's shared domain by default. That's fine at first. But once you're sending real volume, sharing a domain means you're also sharing a reputation with senders you'll never meet. Their spam complaints can drag down your inbox placement.
Since February 2024, Gmail and Yahoo require bulk senders to authenticate their mail, and a branded sending domain is how you do it in Klaviyo. Skip it and your campaigns start landing in spam or getting rejected outright.
This guide walks through what a sender domain is, how it differs from a shared one, the exact steps to set it up, and the mistakes that keep domains stuck on "unverified."
What's a sending domain?
A branded sending domain is a subdomain, like send.yourbrand.com, that you authenticate so Klaviyo sends email as your brand instead of as a shared Klaviyo domain. It carries its own sender reputation with inbox providers, which means your sending habits, not a stranger's, decide where your emails land.
Klaviyo calls this a "branded sending domain." You'll also hear it called a dedicated sending domain or a custom sending domain. They all mean the same thing: mail that's signed with your domain's DNS records instead of Klaviyo's.
The subdomain part matters. Sending from a subdomain like send.yourbrand.com keeps your marketing reputation separate from your main website domain. If a campaign ever triggers complaints, the damage stays contained to the subdomain and doesn't touch the domain your customers use to log in or check out.
Branded or shared domain?
By default, most Klaviyo accounts send from a shared IP and a shared Klaviyo domain. A branded domain switches that to your own subdomain, giving you direct control over your sender reputation. Shared is fine for brand-new, low-volume senders. Branded is the standard once you're sending real campaigns.
On a shared domain, your reputation is pooled with other Klaviyo senders. Most are legitimate, but you don't control their behavior. One bad actor sending spam from the same shared domain can pull down placement for everyone on it.
A branded domain isolates you. Your open rates, complaint rates, and list hygiene are the only signals that count. That's a double-edged benefit: you own the upside and the downside. Clean sending gets rewarded fast, and sloppy sending gets punished just as fast. If your list hygiene is already shaky, fix that before you flip the switch. A quick Klaviyo audit can tell you if you're ready.
Does it help deliverability?
Yes. A branded sending domain is one of the biggest levers for inbox placement, because it lets inbox providers judge your mail on your own track record. It also satisfies the authentication rules Gmail, Yahoo, and Microsoft now enforce for bulk senders.
The numbers back it up. InboxEagle's analysis found that senders using a subdomain averaged a 13.3% spam rate, versus 26.0% for senders mailing from their root domain. That's nearly half the spam placement, just from the domain structure.
Placement is already tight for stores. Deliverability data shows retail and ecommerce inbox placement sits below 80%, meaning more than one in five emails never reaches the inbox on a shared, unauthenticated setup. Our other deliverability guides go deeper on list hygiene and sender reputation.
Then there's the compliance side. Google's sender requirements treat any sender pushing 5,000 or more messages a day to Gmail as a bulk sender. Bulk senders must authenticate with SPF, DKIM, and DMARC, keep their spam complaint rate under 0.3%, and offer one-click unsubscribe. A branded sending domain is what makes that authentication possible. Starting in late 2025, Gmail began rejecting mail that fails these checks, so this isn't optional anymore.
Set up your sender domain
Here's the Klaviyo sender domain setup, start to finish. You'll bounce between Klaviyo and your DNS provider, like Cloudflare, GoDaddy, or Shopify. You can follow along with Klaviyo's branded sending domain guide open in another tab.
- 1. Open the domains settings. In Klaviyo, go to Settings, then Domains, then click Add Domain. Klaviyo suggests a sending subdomain for you. Accept it unless you have a reason not to.
- 2. Copy your DNS records. Klaviyo generates up to three CNAME records (or four NS records) for authentication, plus one TXT record to verify you own the domain. The DKIM records use km1 and km2 selectors for marketing mail.
- 3. Add the records to DNS. Paste each record into your DNS provider's zone exactly as shown. Don't proxy them. Klaviyo's records have to resolve publicly to work, so turn off Cloudflare's orange-cloud proxy for these entries.
- 4. Set up DMARC on your root domain. DMARC lives on your root domain, not the subdomain. A policy of p=none is enough to start. Add it as a TXT record, and your from-address will align with the root domain to pass the check.
- 5. Verify in Klaviyo. Back in Klaviyo, click Verify. Klaviyo also auto-checks every 15 minutes for up to two days. When every record turns green, you're authenticated.
- 6. Activate the domain. Click Activate. Your campaigns and flows now send from your branded subdomain.
DNS changes can take a few minutes or up to 48 hours to propagate. Give it time before assuming something's broken.
Do you need to warm it?
Sometimes. If your domain is brand new or has never sent email, you need to warm it by slowly ramping up volume so inbox providers learn to trust it. If your domain has sent mail before, you can usually skip warming.
Klaviyo's rule is specific. If you're an existing sender moving to a branded domain, you don't have to warm again, as long as the domain has been registered for at least 30 days and you've already used it to send email. That includes sending from it in your friendly from address or through a previous provider.
If you're new to email or the domain has no history, follow the warming process. Start with your most engaged subscribers, the people who opened or clicked in the last 30 to 60 days, and expand from there. Engaged sends build a positive reputation fast. Blasting your whole list on day one does the opposite.
A smart move: use your brand's domain in the friendly from address for 30 days first, build a clean track record, then activate the branded domain. It's the safest on-ramp.
Dedicated IP or domain?
These get mixed up constantly, and choosing wrong costs you. A dedicated sending domain is about authentication and is right for nearly every Shopify store. A dedicated IP is about volume and is wrong for most of them.
A branded sending domain signs your mail with your DNS records. It works at any volume, and it's what Gmail and Yahoo want. Set it up regardless of how much you send.
A dedicated IP is a separate sending address used only by your account. It only helps once you send enough to keep it warm. Deliverability guidance puts the floor around 50,000 to 100,000 emails a month. Below roughly 25,000 a month, a dedicated IP actually hurts you, because inbox providers can't see a steady pattern and stop trusting it. A dedicated IP sending 5,000 emails once a week looks suspicious next to a shared IP with constant, healthy traffic.
So the order is simple. Every store should set up a branded sending domain. Only high-volume senders should even think about a dedicated IP. If you're not sure where your volume lands, our deliverability team can map it before you make a change you'll have to undo.
Fix domain setup errors
Most failed Klaviyo sender domain setups come down to a DNS typo. The values in your DNS have to match what Klaviyo shows exactly, character for character.
- A missing trailing period. Some DNS providers expect a period at the end of the record value. Leave it off and the record won't resolve.
- A record that got overwritten. If a domain won't verify after four days, the records are almost always wrong or overwritten. Real propagation rarely takes that long. Fix the entry and it usually reconnects right away.
- Proxied records. If you turned on Cloudflare's proxy for the CNAMEs, turn it off. They must resolve as plain DNS.
- Wrong DKIM selectors. The km1 and km2 CNAMEs have to match Klaviyo's target values precisely.
Run your records through a free DNS lookup tool like MxToolbox to confirm they're live and pointing where they should. Across the Shopify stores we manage at CartStrings, a stuck domain is almost never a Klaviyo problem. It's one record in the wrong place. Once it's fixed, verification is instant.
If flows and campaigns still aren't sending from your branded domain after activation, double-check that the domain is set as active in your account settings and that your email automations point to it.
Get your domain done right
A Klaviyo sender domain setup is a one-time job with a permanent payoff. You authenticate a branded subdomain, add the DNS records, verify, warm it if it's new, and from then on your emails travel on your reputation, not a stranger's. Given that Gmail and Yahoo now reject unauthenticated bulk mail, it's the price of entry, not a nice-to-have.
The setup itself is quick. Getting it perfectly clean, then keeping your reputation healthy after, is where most stores slip. Across the Shopify brands we manage at CartStrings, tight domain setup and list hygiene are why we average 99.8% inbox delivery.
If your domain won't verify, your open rates are sliding, or you just want it done right the first time, book a call and we'll handle the setup and the reputation work behind it.
Frequently Asked Questions
Do I need a dedicated sending domain in Klaviyo?
If you send campaigns to a real list, yes. Since 2024, Gmail and Yahoo require bulk senders to authenticate their mail, and a branded sending domain is how Klaviyo does that. Only brand-new, very low-volume senders can safely stay on the shared domain for a while.
How long does a Klaviyo sending domain take to verify?
Usually a few minutes to a couple of hours, but DNS can take up to 48 hours to fully propagate. Klaviyo auto-checks your records every 15 minutes for up to two days. If it isn't verified after four days, a record was almost certainly entered wrong.
What's the difference between a branded and shared sending domain?
A shared domain pools your reputation with other Klaviyo senders you don't control. A branded domain sends from your own subdomain, so only your sending habits affect where your emails land. Branded gives you control and meets bulk-sender rules; shared does neither.
Do I have to warm up my sending domain?
Only if it's new or has no sending history. If your domain has been registered for at least 30 days and already sent email, Klaviyo lets you skip warming. New domains should ramp up slowly, starting with your most engaged subscribers.
Does a sending domain improve deliverability?
Yes. Authenticating a branded subdomain isolates your reputation and satisfies Gmail, Yahoo, and Microsoft's rules. Data shows subdomain senders hit spam far less often than root-domain senders, so the domain structure alone can meaningfully lift inbox placement.
