Opensend vs Klaviyo Native Flows: Do You Need Both for Cart Recovery?
Opensend identifies anonymous visitors. Klaviyo native flows send the emails. Learn what each actually solves, where the gap remains, and how to close it.
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TL;DR
- Klaviyo's native abandoned cart flow handles email automation: building the sequence, timing the sends, and tracking conversion. It does not solve identification — it can only email shoppers it already recognizes.
- Opensend solves a specific identification problem: matching previously anonymous, never-before-seen visitors to email addresses so they can enter your Klaviyo flows for the first time.
- Neither tool addresses a separate and often larger gap: existing Klaviyo subscribers whose on-site behavior — Add to Cart, Checkout Started — frequently doesn't reach Klaviyo at all, due to browser tracking limitations.
- For most Shopify stores, the highest-impact setup combines Klaviyo (email automation) with a layer that identifies new anonymous visitors and a separate layer that closes the behavior data gap for existing subscribers.
What each tool actually does
Klaviyo native flows
Klaviyo provides the email automation layer: building abandoned cart and checkout abandonment sequences, timing each email, personalizing content with product data, and reporting on flow performance.
What Klaviyo's native tracking cannot do: identify a shopper who has never provided an email address, or reliably capture behavioral events for shoppers browsing without being logged in, especially under browser privacy restrictions.
Opensend
Opensend identifies anonymous website visitors — people with no prior relationship to your brand and no email on file — and matches them to an email address through its identity network. Once matched, that contact can be synced to Klaviyo, where they enter your existing flows for the first time.
What Opensend solves: growing the population of contacts Klaviyo can email, by converting never-before-seen visitors into known profiles.
What Opensend does not solve: the behavior of shoppers who are *already* on your Klaviyo list. If an existing subscriber visits anonymously, adds a product to cart, and leaves, Opensend's identification layer has nothing to contribute — that shopper is already identified. The problem is that Klaviyo doesn't know what they just did.
Definition: two different problems
Visitor identification is the process of matching an anonymous, previously unknown visitor to an email address.
Behavior data completeness is the process of ensuring that known subscribers' on-site actions — Add to Cart, Checkout Started — are successfully captured and matched to their existing profile, even when native browser tracking fails to register the event.
These are not the same problem, and tools built for one do not automatically solve the other.
Comparison table
| Capability | Klaviyo native | Opensend | The remaining gap |
|---|---|---|---|
| Send automated abandoned cart emails | Yes | No (relies on Klaviyo) | — |
| Identify never-before-seen anonymous visitors | No | Yes | — |
| Track behavior for known subscribers browsing anonymously | No (native tracking limits apply) | No (not its function) | Yes — unaddressed by either tool |
| Sync new identified contacts to Klaviyo | N/A | Yes | — |
| Trigger existing flows for previously untracked subscriber behavior | No | No | Yes — unaddressed by either tool |
How the gap shows up in practice
Consider a Shopify store using both Klaviyo and Opensend. A first-time visitor browses anonymously, gets identified by Opensend, and is synced to Klaviyo — this part works as intended, and they can now enter the abandoned cart flow on a future visit.
But a separate, often larger group remains unaddressed: shoppers who are *already* Klaviyo subscribers, who return to the site, browse anonymously (not logged in, on a different device, with expired cookies), add something to cart, and leave. Opensend has no role here, since the shopper is already identified. The issue is that Klaviyo's native tracking doesn't reliably capture their Add to Cart event during this particular visit.
Internal advertising data has shown this second gap to be substantial — native tracking capturing as little as 14% of relevant shopper behavior events, even for known subscribers, with the potential to lift that to 55%+ when behavior data is more completely connected.
Where each solution fits in a complete recovery stack
| Layer | Tool | What it adds |
|---|---|---|
| Email automation | Klaviyo | Builds and sends the abandoned cart and checkout abandonment sequences |
| New visitor identification | Opensend (or similar) | Converts never-before-seen anonymous visitors into known, emailable contacts |
| Existing subscriber behavior data | A dedicated behavior-data layer | Connects on-site actions (Add to Cart, Checkout Started) from already-known subscribers back to their Klaviyo profile, triggering flows that would otherwise never fire |
A complete setup typically benefits from having all three layers, since they address non-overlapping populations: new anonymous visitors, and existing subscribers whose current-session behavior goes untracked.
How to tell which gap your store actually has
Step-by-step diagnostic:
- Check your current email list growth rate. If it's slow and most traffic is brand-new visitors with no prior relationship to your store, visitor identification (Opensend or similar) addresses a real gap.
- Check your Klaviyo flow entries against your total cart abandoners (flow entries ÷ Shopify cart additions). If this ratio is low — commonly 14-15% — even for contacts already on your list, the behavior data gap is likely your larger opportunity.
- Most established Shopify stores with an existing subscriber base of any meaningful size find the second gap to be the larger of the two, simply because their subscriber list already contains people whose current behavior goes unseen.
Why this distinction matters for budget allocation
Spending exclusively on visitor identification tools while ignoring the behavior data gap means a portion of your existing, already-acquired subscriber base continues to go unreached for ongoing on-site behavior — the same subscribers you've already paid to acquire and grow.
Closing the behavior data gap for existing subscribers is the layer Attribuly's recovery tools are built around, working alongside (not replacing) your existing Klaviyo flows, with a guaranteed return of at least $4 in recovered revenue for every $1 invested.
Common mistakes
Mistake 1: Treating visitor identification as a complete recovery solution
Identifying new anonymous visitors is valuable, but it does nothing for the existing subscribers whose on-site behavior already goes untracked.
Mistake 2: Assuming a growing Klaviyo list means the reach problem is solved
List size and behavioral visibility are independent. A larger list with the same native tracking limitations still only sees 14-15% of relevant behavior.
Mistake 3: Running two identification tools instead of identifying the actual gap
Some stores add multiple visitor identification tools assuming more coverage, without checking whether their real gap is in new-visitor identification or existing-subscriber behavior data.
Mistake 4: Not measuring which gap is larger before choosing a tool
Running the diagnostic in this article (checking list growth rate and flow entry ratio) takes under 30 minutes and determines which investment will have a larger impact.
Next step
Run the two-part diagnostic: check your email list growth rate, then check your Klaviyo flow entry ratio against total cart abandoners. The result will tell you whether visitor identification, behavior data completeness, or both represent your next investment.
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