Inconsistency on lineItem id on checkout_completed web pixel event

Technical Q&A

Topic summary

  • Issue: In the checkout_completed web pixel event (Checkout), the values of lineItems[0].id and lineItems[0].variant.id are inconsistent.

  • Observation: Sometimes both fields contain the same value; other times lineItems[0].id shows a different, seemingly unrelated string. This raises uncertainty about what each field is intended to represent in this context.

  • Request: Clarification on the correct meaning and expected behavior of lineItems[0].id versus lineItems[0].variant.id in the event payload.

  • Context: Linked reference to a Shopify CLI GitHub thread indicating others have encountered similar behavior.

  • Status: No answers or resolution provided in the thread; the question remains open and awaiting guidance.

Summarized with AI on December 26. AI used: gpt-5.
1

Hi, I have a question.

What the lineItems[0].id and lineItems[0].variant.id represents (in the Checkout, to be more specific in the “checkout_completed” event)? Sometimes I’ve found they both shows same value, sometimes they are not (on id something irrelevant string id generated). Can anyone has the idea on this to share?

Thank you.

I’m not the only one experiencing the issue. Ref : https://github.com/Shopify/cli/issues/1630#issuecomment-1485554810