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TL;DR: A dedicated sending domain sends your Klaviyo email under your own brand instead of a shared pool, so mailbox providers judge your reputation on your sending alone. Almost every Shopify brand should have one. A dedicated IP is a different thing and only pays off past about a million emails a month. If your domain is brand new, warm it over 30 days by starting with your most engaged customers and growing volume slowly.
A dedicated sending domain is a branded subdomain that sends your Klaviyo email under your own name instead of a shared pool, and it's now table stakes for any Shopify brand emailing 5,000 or more people a day. Google and Yahoo tightened their rules in 2024, and the brands that ignored the change watched their open rates slide. Here's the good news. Setting up a dedicated sending domain isn't hard, and the payoff is real: better inbox placement, a reputation you actually control, and email your customers trust because it comes from your brand. The part most guides get wrong is warming. They treat a dedicated sending domain and a dedicated IP like the same thing, then scare small stores into a process they don't need. This guide clears that up. You'll learn what a dedicated sending domain is, whether you need one, how it's different from a dedicated IP, how to set it up in Klaviyo, and the 30-day warmup plan that keeps your reputation intact. Across the Shopify stores we manage at CartStrings, getting this right is the foundation for a 99.8% inbox delivery rate.
What is a sending domain?
A sending domain is the domain your email is technically sent from. A dedicated sending domain, which Klaviyo calls a branded sending domain, is a subdomain like send.yourstore.com that only you use, so inbox providers tie your reputation to your brand instead of to strangers on a shared pool.
By default, new Klaviyo accounts send from a shared domain that Klaviyo owns. Your email still works, but your reputation is mixed in with every other sender on that pool. A dedicated sending domain moves you onto your own name. It also lets you pass DMARC alignment, which Gmail now checks for bulk senders. This is a low-risk change that almost every store should make.
Branded vs shared domain
On a shared domain, one bad sender in the pool can drag down everyone's inbox placement, and you have no control over it. On a dedicated sending domain, your reputation is yours alone. Good sending helps you, and nobody else's mistakes hurt you.
There's a catch worth knowing. A brand new dedicated domain starts with zero reputation. A shared pool already has an established one. That's why you warm a new domain slowly instead of blasting your full list on day one. We cover the exact schedule below.
For most Shopify brands, the trade is worth it. You give up a borrowed reputation for one you build and keep. If your deliverability is already shaky, a Klaviyo audit will tell you whether your domain, your list, or your content is the real problem before you change anything.
Domain or dedicated IP?
A dedicated sending domain and a dedicated IP aren't the same thing. A dedicated domain sets your reputation at the brand level and suits senders of any size. A dedicated IP is separate infrastructure that only helps once you send serious volume, and it can hurt smaller stores.
This is the mistake that trips people up. They read that you should warm a dedicated IP and panic, when all they actually need is a branded sending domain on Klaviyo's shared IP pool.
Here's the rule. A branded sending domain is for everyone, free plans included. A dedicated IP is recommended only if you consistently send over a million emails a month, and Klaviyo approves it case by case. Below that, a dedicated IP works against you. Reputation is like a credit score, and mailbox providers need steady volume to remember you. A low-volume sender on a dedicated IP looks like a stranger every send, so a well-run shared IP pool beats it. Domain reputation now carries more weight than IP reputation anyway, so the branded domain is where your effort belongs. If you're facing a real deliverability problem, our managed deliverability work starts here.
Set up a sending domain
Setting up a dedicated sending domain in Klaviyo takes a few minutes, plus DNS time. Here's the short version:
- Open your domain settings. In Klaviyo, go to Settings, then Email, then Domains, and add a branded sending domain.
- Add the DNS records. Klaviyo gives you CNAME and TXT records. On Shopify-managed DNS, add them as static CNAMEs, since Shopify DNS won't accept NS records. Klaviyo sets up SPF and DKIM for you.
- Match your root domain. The sending domain's root should match the address your email comes from, so send.yourstore.com pairs with hello@yourstore.com.
- Verify. Go back to Klaviyo and click Verify. DNS can take up to 48 hours to propagate, and green checkmarks mean you're live.
- Confirm DMARC. If you send over 5,000 emails a day to Gmail, you also need a DMARC record set to at least p=none, plus one-click unsubscribe.
Google spells out these authentication rules in its email sender guidelines, and they apply to every email platform, not just Klaviyo.
What is domain warming?
Domain warming is the process of building a good reputation on a new sending domain by starting with a small, engaged audience and raising your volume slowly. It tells inbox providers you're a trusted sender before you send at full scale.
A cold domain has no track record. If you blast your entire list on day one, mailbox providers see a sudden spike from an unknown sender and treat it like spam. Warming avoids that. You send to the people most likely to open and click first, stack up positive signals, then widen your audience step by step.
Klaviyo's own rule is simple: never increase volume by more than 2x from one send to the next, and keep sending on a steady cadence of two to four times a week. Gaps in sending slow the whole thing down.
The 30-day warmup plan
Warming a new dedicated sending domain takes up to 30 days for most lists. Here's the plan Klaviyo recommends, and the one we run for clients:
- Weeks 1 to 2. Send only to your 30-day engaged segment, people who clicked or subscribed in the last 30 days. Keep your first campaign under 10,000 recipients. Aim for open rates above 30%, and never let them fall below 20%.
- Weeks 3 to 4. If open rates hold above 20%, widen to your 60-day engaged segment and send up to three times a week.
- After 4 weeks. Relax to 90 days, then 120, then 180 over the following weeks, checking your open rate at each step.
- Turn on safe flows first. Welcome, abandoned cart, and browse abandonment are high-engagement and safe to enable early. Hold winback and sunset flows until warming is done.
The gate is your open rate. If it dips below 20%, stop widening and stay on your current segment until it recovers. Klaviyo's warming guide lays out the same segment ladder. Watch your bounce rate, keeping it under 2%, and your spam complaint rate, keeping it under 0.1%, the whole way. This is exactly the kind of setup our email campaign management handles, so a launch never torches your reputation.
Do you need to warm?
Not always. If you're moving to Klaviyo with a domain that's at least 30 days old and has already sent email, its reputation carries over and you can skip the full warmup. A brand new domain, or a newly registered one, always needs warming.
So a store that's emailed from yourstore.com for a year and switches to a send.yourstore.com subdomain has a head start. A store spinning up a fresh domain does not. When in doubt, warm it. The downside of warming a domain that didn't need it is a few slow weeks. The downside of skipping warming on a cold domain is landing in spam and digging out for months.
If you're migrating from Mailchimp or another platform, bring your engagement data with you so you can build those 30, 60, and 90-day segments accurately. Guessing here is what sinks migrations.
Get your setup right
A dedicated sending domain is one of the highest-impact, lowest-risk moves in email. It puts your reputation in your own hands, keeps you compliant with Gmail and Yahoo's rules, and makes your email look like it actually comes from your brand. Set it up, authenticate it, and warm it patiently by leading with your most engaged customers. Do that and your campaigns land where they belong, in the inbox.
Most stores get the setup right and then rush the warmup, or confuse a dedicated domain with a dedicated IP and overthink the whole thing. If you'd rather have it done right the first time, that's what we do. Across the Shopify brands we manage at CartStrings, clean deliverability is what holds up a 39% average open rate. Book a call and we'll take a look at your setup.
Frequently Asked Questions
Do I need a dedicated domain?
If you send marketing email from Klaviyo, yes. A dedicated (branded) sending domain gives you a reputation you control, and it's required in practice once you send 5,000 or more emails a day to Gmail. Even below that threshold it improves inbox placement and brand trust, so nearly every Shopify store benefits from one.
Domain vs dedicated IP?
A dedicated sending domain sets your reputation at the domain level and suits senders of any size. A dedicated IP is separate infrastructure Klaviyo reserves for very high senders, usually over a million emails a month. Below that volume a dedicated IP hurts more than it helps, because you can't send enough to keep it warm.
How long does warming take?
Plan for about 30 days, though it can run from two weeks to a couple of months depending on your list size and how often you send. Sending consistently, two to four times a week, warms a domain faster than sending in occasional bursts.
Skip warming when moving?
Sometimes. If your domain has been registered for at least 30 days and you've already sent email from it, its reputation carries into Klaviyo and you can skip the full warmup. A brand new or newly registered domain always needs warming from scratch.
What if I skip warming?
Blasting a full list from a cold domain usually sends a big chunk of your email straight to spam. That early spam placement teaches mailbox providers to distrust you, and recovering can take weeks or months. Warming is slower up front but far cheaper than digging out of a reputation hole.
