Hi @GrahamS and thanks for your reply.
I retried the same thing a couple of days later and all of a sudden it started working. I have no idea why it didn’t work the first couple of times. Perhaps there was some technical issue…
Best regards,
Johnny
Topic summary
Goal: enable backorders (orders for temporarily out-of-stock products) via the API.
Configuration: Admin > Products > Inventory, with “Continue selling when out of stock” enabled.
Issue: Creating an order for an out-of-stock product initially returned HTTP 422 with message “Unable to reserve inventory.” The requester sought guidance on implementing backorders and relevant API documentation.
Investigation: A responder asked for the x-request-id (a unique request identifier used to trace and diagnose API calls) to examine potential causes.
Update: After retrying a few days later, the same flow began working without changes. The original poster suspects a transient technical issue but has no confirmed root cause.
Outcome: No specific fix or documentation link was provided. The practical problem appears resolved, and orders for out-of-stock items now proceed when “Continue selling” is enabled.
Status: Effectively resolved; outstanding question remains about the initial 422 error’s cause.