Why Are Klaviyo Emails Going to Spam?

When Klaviyo emails go to spam, the cause is almost never Klaviyo's servers. It's usually one of three things: you're still sending on Klaviyo's shared domain instead of your own branded sending domain, you're mailing people who stopped engaging months ago, or your list has quality problems (bought, scraped or old addresses) that are dragging down your reputation. Fix those in that order and most Klaviyo spam problems go away.

The good news is that Klaviyo gives you more data to diagnose this than most platforms. The bad news is that its defaults make it very easy to email everyone, every time.

How Klaviyo sending works

By default, Klaviyo says most accounts begin sending from a shared IP and a shared Klaviyo domain. Your recipients may see "via klaviyomail.com" next to your name in Gmail. Your reputation is partly pooled with every other sender on that shared setup.

A branded sending domain (Klaviyo used to call it a dedicated sending domain) moves the technical parts of your mail onto a subdomain you own, like send.example.com. DKIM signs with your domain, the "via" line goes away, and mailbox providers start judging you on your own behavior. Klaviyo also lets you set up separate sending domains for marketing, transactional and service email, so a bad marketing week doesn't drag down your order confirmations.

That last point matters more than it sounds. Gmail and Yahoo judge reputation largely by domain now. If you're sending on a shared domain, you're not building any reputation of your own, good or bad.

Common causes, most likely first

1. Sending to unengaged profiles. Campaigns to "everyone" or to a list that includes people who haven't opened or clicked in a year. Mailbox providers notice when a large share of your mail sits unread or gets deleted, and they start filtering the rest.
2. No branded sending domain. You're still on the shared Klaviyo domain, so DMARC alignment depends on Klaviyo's setup, not yours, and you have no domain reputation of your own. Since Gmail and Yahoo's 2024 bulk sender rules, anyone sending more than 5,000 messages a day to Gmail needs SPF, DKIM and DMARC with alignment to the From domain.
3. List quality. Imported lists, old lists from a previous ESP that were never cleaned, contest sign-ups, or co-registration data. These bring hard bounces and spam traps (addresses that exist only to catch senders who don't manage their lists). See what 550 5.1.1 bounces tell you and why your ESP can't fix a spam trap problem.
4. Spam complaints. Sending too often, sending content people didn't sign up for, or making unsubscribe hard. Klaviyo's own benchmark calls a spam complaint rate under 0.01% healthy and over 0.05% a problem. Gmail's hard ceiling is 0.3%, and you want to be nowhere near it. The spam rate threshold guide explains how Google counts it.
5. A sudden volume jump. Black Friday sends to segments you haven't mailed in months, or a newly migrated account sending full volume on day one. Klaviyo recommends warming new accounts and newly registered domains (under 30 days old) over the first 2 to 4 weeks.

How to diagnose it

1. Check your sending domain. In Klaviyo, look at your domain settings and confirm a branded sending domain is set up and verified. Then send a test to a Gmail address and look at the sender line. If you see "via klaviyomail.com," you're on the shared domain.
2. Check authentication on a real message. In Gmail, open the test, choose "Show original," and confirm SPF, DKIM and DMARC all say PASS. Paste the headers into the header analyzer to see which domain each check used. You want DKIM signed with d=example.com or d=send.example.com, not a Klaviyo domain.
3. Open the deliverability hub. Klaviyo's deliverability hub (under Analytics) gives you an overall score from 0 to 100 and flags high bounce, spam complaint and unsubscribe rates. Look at the trend, not the single number.
4. Break it down by mailbox provider. Klaviyo's deliverability reporting can split metrics by provider. If Gmail opens and clicks dropped while Yahoo and Microsoft held steady, you have a Gmail problem, not a content problem. Klaviyo recommends checking complaint rates per mailbox provider for exactly this reason.
5. Check Google Postmaster Tools. If you've set up a branded sending domain, verify it in Google Postmaster Tools to see Gmail's view of your spam rate and authentication.
6. Ignore open rates as a primary signal. Apple Mail Privacy Protection inflates opens, and Klaviyo includes those machine opens in its benchmarks. Clicks and conversions per provider are a more honest signal.

How to fix it

1. Set up a branded sending domain. Use a subdomain you don't use for anything else (Klaviyo suggests send). Klaviyo supports dynamic routing (NS records) or static routing (CNAME records), and can publish them for you through Entri. Keep your From address on your main domain (hello@example.com), not the sending subdomain, or replies won't arrive.
2. Publish DMARC on your root domain. Klaviyo can generate a starter p=none record. Use the DMARC generator if you want to build your own, and the email checker to confirm it's live. The authentication overview explains how SPF, DKIM and DMARC fit together.
3. Shrink to engaged segments. Build a segment of profiles who clicked, opened (excluding Apple machine opens where you can), visited the site or bought within a recent window, and send campaigns to that segment only. Pull back everyone else for now.
4. Warm back up. If your reputation is already damaged, send to your most engaged profiles first, at lower volume, and widen the segment gradually over a few weeks as placement improves. Don't try to fix a bad Gmail reputation by sending more.
5. Run a sunset flow. Send a short re-engagement series to profiles who have gone quiet, then suppress anyone who doesn't respond. Klaviyo's own guidance supports sunsetting unengaged subscribers. Yahoo's sender guidance says the same: send reconfirmation messages to inactive subscribers and remove invalid recipients promptly.
6. Clean up list sources. Stop importing lists you didn't collect yourself. Use double opt-in on sign-up forms that attract fake or mistyped addresses. Check the bounce details tab in the deliverability hub for patterns.
7. Make unsubscribing easy. One-click unsubscribe is required for bulk senders at Gmail and Yahoo, and Klaviyo handles the header for you. Make sure the footer link is visible too. A person who can't find unsubscribe clicks "Report spam" instead.

How to confirm it's fixed

Placement recovers over weeks, not days. Watch these:

• Gmail spam rate in Postmaster Tools staying well under 0.1%.
• Klaviyo's deliverability score trending up and the high-complaint and high-bounce alerts clearing.
• Clicks and conversions per mailbox provider recovering, especially at the provider that dropped first.
• Seed or panel tests showing inbox placement, if you use them.

How to keep it from coming back

• Send campaigns to engaged segments by default. Mailing the full list should be a deliberate exception, not a habit.
• Keep a sunset flow running all the time, not just after a problem.
• Watch complaint and bounce rates per send, per provider. A single bad send to an old segment can undo weeks of good behavior.
• Treat big seasonal pushes as warmups: start widening segments weeks ahead, not the morning of.

If you're comparing platforms, the same patterns show up at Mailchimp, SendGrid and HubSpot. The ESP changes. The causes mostly don't.

When to get help

If you've set up the branded domain, tightened your segments, and Gmail still sends you to spam after a few weeks, or you can't tell whether the problem is reputation, list quality or content, it's worth having someone look at your data with you. Get in touch.

FAQ

Is Klaviyo bad for deliverability?

No. Klaviyo's infrastructure isn't the usual problem. Mailbox providers judge your domain, your list and how your recipients react to your mail. A sender with good data does fine on Klaviyo, and a sender with bad data has the same problem on any platform.

Do I need a branded sending domain in Klaviyo?

If you send at any real volume, yes. It lets your mail pass DMARC with your own domain, removes the "via klaviyomail.com" line, and means you build your own reputation instead of sharing one. Gmail and Yahoo require aligned authentication for bulk senders.

Why are my Klaviyo open rates high but sales dropped?

Apple Mail Privacy Protection opens can make open rates look healthy even when mail is landing in spam at Gmail. Check clicks and conversions broken out by mailbox provider. A Gmail-only drop in clicks is a common sign of a Gmail placement problem.

Will switching from Klaviyo to another ESP fix spam problems?

Usually not. If the cause is your list or your sending habits, it follows you. If your domain reputation is damaged, it follows you too, because it's attached to your domain, not to Klaviyo.