Shopify doesn't send fulfillment request notification

Retired Boards Appdev Fulfillment Api
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Topic summary

Issue: A custom fulfillment service app auto-creates fulfillment requests from order webhooks. For orders containing one specific product, Shopify never sends the expected “fulfillment request notification” back to the service, stopping the flow. Orders with all other products work, and the order timeline shows the app did request fulfillment.

Context: Normal flow is webhook → validations → create fulfillment request → Shopify sends notification to the fulfillment service → fulfillment. A “fulfillment service” is a third‑party integration that fulfills orders; the “fulfillment request notification” is Shopify’s callback asking the service to fulfill.

Troubleshooting: The problematic product’s settings appear identical to working products. The service responds with HTTP 200 to all Shopify calls; no excessive errors/timeouts that might cause Shopify to pause communication.

Ask: Seeking any way to diagnose why Shopify would not send the fulfillment request notification (e.g., logs, reasons, specific product flags) for that product.

Status: Unresolved; no explanation or solution provided yet.

Summarized with AI on January 4. AI used: gpt-5.
1

Hello,

we handle fulfillments for our customer by installing a fulfillment service, listening to order webhooks and automatically create fulfillment requests (so the merchant doesn’t have to do it manually).

Everything works fine: order webhook is received, some validations pass, we create the fulfillment request, receive the fulfillment request notification and eventually fulfill the order.

But: There is one product in the merchant’s shop that - for whatever reason - breaks this workflow.

If an order, that contains this product, is created, we receive the order webhook, perform our validations and create the fulfillment request. And at that point the whole workflow stops. When we have a look into such an order’s history we can see that our app has requested the fulfillment for that order, but Shopify did never send the fulfillment request notification for that order.

It works fine with all other products, except this specific one.

I already compared the product’s details with a “working” one - everything has been set up the same way. No differences (except for the product details, of course).

Question: Is there any way to find out why Shopify might not send fulfillment request notifications?

What I’ve noticed so far is that Shopify stops communicating with our fulfillment service when there have been too much error responses or timeouts. But that’s not the case here. Every call to our fulfillment service results in a HTTP 200.

Thank you very much in advance

Alex