Woo Commerce to Klaviyo API integration, not syncing partial orders

Question

Hello,

Has anyone used the REST API endpoints to sync partial orders from Woo into Klaviyo? Only some partial orders are being synced and some aren’t, and we can’t figure out why. This is what was set up by a developer:

Endpoints used

- https://a.klaviyo.com/api/events → new Events API (auth via Klaviyo-API-Key <PRIVATE_KEY>)
- https://a.klaviyo.com/api/track → legacy Track API fallback (uses token: <PUBLIC_SITE_ID>)

Summary

- Implemented 30% deposit + 5×14% installment logic.
- Adjusted checkout totals, displayed deposit/installments preview.
- On order creation: saves deposit/installment metas.
- On “Thank You”: creates 5 child orders (one per installment).
- Fires 3 Klaviyo events:

- Installment Plan Created (after checkout)
- Deposit Paid (parent order payment)
- Installment Paid (child order payment)
- Logs output with prefix [ILO Override].

Any tips or advice would be greatly appreciated.

Thanks

Emma

cadence · Answer

Hey ​@iloretreat, I’m sorry you’re running into problems here!https://a.klaviyo.com/api/track is retired and should not be used in production workflows. The API is no longer documented, so it’s quite possible this is causing your syncing issues. I’d recommend updating everything to use the new POST /api/events endpoint. If you need to send events client-side, you can use the POST /client/events endpoint instead.When you say some of the orders are not syncing, do you mean the initial Installment Plan Created and Deposit Paid events aren’t coming through, or that the Installment Paid events are missing?Klaviyo provides a helpful API logs tool that you or your developer can check: https://www.klaviyo.com/developer-tools/logs. Try extending the time window (it supports up to 14 days) and searching by event name, such as Installment Plan Created, to see whether those events are being sent to Klaviyo and in what format.My best hypotheses here are:Not all events are being sent to Klaviyo as expectedSome API calls are being rejected, causing dropped dataNewer API calls (to /api/events) are working, but legacy calls to /api/track are not syncing properlyCadence/Book a demo

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