Version conflicts, concurrent writes, and precondition failures.
Last reviewed: March 1, 2026|19 mapped errors|Page 2 of 2
Conflict errors occur when current resource state no longer matches caller assumptions, commonly under concurrent writes or stale version tokens.
Provider-specific error pages mapped to this category (19 total). Showing 16-19.
GCP FAILED_PRECONDITION means the operation cannot run because required resource or workflow state is not currently satisfied.
HTTP 409 Conflict means the request conflicts with the current state of the target resource.
HTTP 412 Precondition Failed means a conditional request precondition evaluated to false on current resource state.
HTTP 428 Precondition Required means the origin requires conditional requests to prevent lost updates.
Compare Guide
Choose 412 when If-Match or If-Unmodified-Since checks fail; choose 409 for state conflicts without failed precondition headers during concurrent updates.
Playbook
Use this playbook to separate true write conflicts from stale precondition failures, then apply safe re-fetch, optimistic-lock, and retry choices.
409 indicates a state conflict during processing, while 412 indicates a declared precondition (for example If-Match) evaluated to false.
Retries increase concurrent write pressure and can replay stale versions. Without fresh reads and merge logic, conflict rates rise quickly.
Use optimistic concurrency with version tokens and idempotency keys, then isolate high-contention keys with targeted partitioning strategies.