Duplicate payment ID used to generate transaction from the same cart

Topic summary

  • Issue: A Shopify app developer reports receiving the same payment ID more than once from Shopify when creating transactions to their payment gateway for the same order (example ID provided).

  • Expected behavior: Each request from Shopify should carry a unique payment ID (a unique identifier for a payment request/transaction attempt).

  • Request: Seeks clarification on whether this behavior is expected and what could cause duplicate payment IDs for the same order.

  • Outcome/Status: No answers or confirmed causes provided. The question remains open with no resolution or action items yet.

Summarized with AI on January 13. AI used: gpt-5.

We’re encountering an issue in our shopify plugin wherein Shopify sends the same payment ID (e.g.rmwAe2IRXtD8Pk9FhTq8HI5CM) more than once when creating a transaction towards our payment gateway for the same Order.

The expectation is that every request from Shopify should have a unique payment ID.

Can someone clarify this behavior? What may possibly cause such scenario?