In April 2026, Shopify webhooks pinned to API version 2025-07 began intermittently arriving without the id field. Delivery succeeded. The HTTP headers said 2025-07, as subscribed. Handlers returned 200. Nothing in the delivery path had anything to report, because from the delivery path's point of view nothing had gone wrong.
This is a walkthrough of that incident: what it looked like from the receiving end, why delivery monitoring cannot catch this class of failure by design, and a reproduction you can run against sanitized fixtures.
The incident is real and resolved. The primary source is the Shopify Developer Community thread Webhooks sometimes sent with wrong API version payload. Everything attributed to Shopify below is quoted from it.
What it looked like
On 13 April 2026, a developer posting as mropanen opened a thread reporting that checkouts/update webhooks were "intermittently arriving with the wrong API version payload."
