HubSpot and Klaviyo for E-commerce: Which System Owns Which Email, and How the Sync Should Work

An e-commerce brand that runs HubSpot and Klaviyo has two systems that can email the same person, two consent records, and a store feeding both. The integration question people ask is "how do I connect them". The question that decides whether it works is "which system owns which message". This is the split INSIDEA writes down before any build, and what the connector between the two does and does not do.

Every vendor fact below was read in the vendor's own documentation on 2 October 2026, with the page's last-updated date where it shows one.

Which system should own which email, HubSpot or Klaviyo?

Klaviyo owns every message triggered by shopping behaviour: welcome, browse and cart abandonment, post-purchase, replenishment, win-back, and consumer campaigns. HubSpot owns every message tied to a sales or service relationship: wholesale and partnership nurture, sales sequences, one-to-one email and ticket replies. No message has two owners.

The rule that keeps this honest: a person is either a consumer audience member or a sales-owned contact for marketing purposes, and the system that owns their audience is the only one that sends them marketing email. A wholesale buyer who also shops on the store is where the two overlap, and that case gets its own line in the document.

Our HubSpot vs Klaviyo comparison covers why the split falls this way, and the older Klaviyo vs HubSpot post covers the choice if you only want one.

Is there a native HubSpot and Klaviyo integration?

No vendor-built one. Klaviyo's help center states that Klaviyo does not have a built-in integration with HubSpot. The Klaviyo app on the HubSpot App Marketplace, and the HubSpot app on Klaviyo's marketplace, are both built by a third-party developer, KAV Labs, on its own paid subscription.

The sources: Klaviyo's How to migrate from HubSpot article, last updated 6 August 2025, and the Klaviyo listing on the HubSpot App Marketplace, which names KAV Labs as the provider.

You have three ways to connect the two:

• The KAV Labs app. Fastest to install. What it syncs is set by the developer, covered in the next section.
• Middleware such as Make or Zapier. Useful for one or two narrow flows, for example pushing a HubSpot list into a Klaviyo list. You maintain every scenario yourself.
• Custom API work. The route when you need rules the app does not offer, such as enforced suppression in both directions. Our custom HubSpot integrations page covers how we scope it.

Because the app is third party, read its reviews and install count on the listing before you rely on it, and ask who will maintain the connection after go-live.

What does the connector sync, and what does it leave out?

Per the developer's documentation, every HubSpot contact with an email becomes a Klaviyo profile, and HubSpot lifecycle and deal events become events you can trigger Klaviyo flows from. Klaviyo email and SMS engagement appears on the HubSpot contact timeline. Klaviyo profiles are never created in HubSpot as new contacts.

Three details from KAV Labs' HubSpot documentation, read 2 October 2026, change how you design around it:

• Contacts flow one way. HubSpot to Klaviyo only. A shopper who exists only in Klaviyo will not appear in HubSpot through this app.
• Consent is visible, never enforced. Each system's consent state shows as a property in the other. The documentation says you must build your own segment or flow filter to suppress on it, and that re-subscribes are never pushed automatically.
• One Klaviyo account connects to one HubSpot portal. Multi-brand setups need a separate install per portal.

The HubSpot marketplace listing describes the sync as two-way across more objects than the developer's documentation does. Where the two differ we have followed the developer's documentation; test the direction of each object in a sandbox before you design on it.

How should store data reach each system?

Directly from the store, to each system separately. Shopify sends Klaviyo order and onsite events in real time. Shopify sends HubSpot customers, products, orders and abandoned checkouts through HubSpot's own data sync, within 10 minutes of a change. Do not relay orders through HubSpot to reach Klaviyo.

What each path carries:

• Shopify to Klaviyo. Checkout Started, Placed Order, Ordered Product, Fulfilled Order, Refunded Order, shipment events, Viewed Product, Added to Cart and marketing consent. Klaviyo says event data appears within a few seconds. Source: Shopify data reference, last updated 18 November 2025.
• Shopify to HubSpot. Contacts, companies and products sync both ways; orders and carts sync from Shopify to HubSpot only. Shopify metafields and product variants do not sync. Source: Connect HubSpot and Shopify, last updated 22 June 2026.

Those timings are the reason for the ownership table. A cart email built on data that arrives within seconds belongs in Klaviyo. HubSpot's copy of the order is for the rep, the service agent and the revenue report.

What does running both cost, and where do the bills overlap?

Three bills move: the connector, Klaviyo's active profiles and HubSpot's marketing contacts. The connector is $29 a month for up to 1,000 contacts, $79 for up to 5,000 and $179 for up to 15,000. The other two depend on which contacts you let cross between the systems.

A worked example. A brand has 60,000 consumer profiles in Klaviyo and 1,800 wholesale contacts in HubSpot.

• Connector. If only the 1,800 wholesale contacts live in HubSpot, the Growth tier covers it: $79 a month, $948 a year. If the Shopify sync has also put 60,000 customers into HubSpot, every one with an email counts, and the published tiers stop at 15,000. The developer's documentation says contacts over the cap are blocked until you upgrade; we have not seen a published price above 15,000.
• Klaviyo. Klaviyo bills on active profiles, meaning any profile that can be emailed whatever its consent status; suppressed profiles are not billed. The 1,800 wholesale contacts pushed in become 1,800 more billable profiles unless you suppress them. Source: How Klaviyo billing works, last updated 25 March 2026.
• HubSpot. Contacts created by an installed app are set as non-marketing by default, and non-marketing contacts do not count toward your contact tier. They can still receive one-to-one email, sequences and transactional email, but not marketing email. Sources: marketing contacts settings for integrations, last updated 10 October 2025, and Understand marketing contacts, last updated 14 September 2026.

So the first design decision is whether consumers need to be in HubSpot at all. If no rep or service agent ever touches them, leave them in Klaviyo and keep all three bills small.

How long does it take, and who does the work?

The connector installs in an afternoon. The work around it takes longer: writing the ownership rule, building suppression both ways and testing with real records. INSIDEA plans three weeks for audit and architecture, and most e-commerce builds go live between week 6 and week 12.

Three people need to be in the room: the HubSpot admin, the lifecycle marketer who owns Klaviyo, and someone with authority over consent and privacy. The order we work in:

1. Write the ownership table and sign it off.
2. Decide which contacts cross, in which direction, and what that does to each bill.
3. Build suppression: a Klaviyo segment that excludes HubSpot opt-outs, and a HubSpot list that excludes Klaviyo unsubscribes.
4. Test end to end with real records before anything sends, including one person who is both a wholesale buyer and a shopper.
5. Switch on, then read the first week of sends in both systems side by side.

If you are a high-volume DTC brand with no sales team, no wholesale channel and no service desk, you do not need this project. Klaviyo and your store's own customer tools cover the motion, and a CRM would add cost without a job to do.

How INSIDEA runs HubSpot and Klaviyo together

INSIDEA is an Elite HubSpot Partner rated 4.99 across 500+ verified reviews, holds HubSpot's Custom Integration accreditation, and is a member of Klaviyo's K:Partners agency program. For e-commerce brands we write the ownership rule into the architecture document before anything is built, name the connector and who maintains it, and build suppression in both directions. First Klaviyo flows are live within two weeks. Engagements are a fixed fee, scoped at proposal, from $2,000; HubSpot, Klaviyo and connector subscriptions are paid to the vendors. The HubSpot partner for e-commerce and Klaviyo page has the full plan, the Klaviyo service page covers the lifecycle work, and e-commerce RevOps covers the rest of the stack.