Invalid State Transition

Overview

Invalid State Transition occurs when an event or command conflicts with the current authoritative state. A formal State Machine defines which source states, events, guards, and destination states are valid.

Invalid transitions can result from delayed events, duplicate delivery, race conditions, stale user interfaces, manual edits, or integration bugs. The event itself can be genuine but no longer applicable after another process has advanced the record.

The system should compare the expected current version or state atomically before applying a change. This prevents two workers from both updating the same payment and reduces Duplicate Processing .

Rejection should return a stable reason and preserve event ID, actor, current state, requested state, timestamp, and relevant parameters. Operators need enough information to decide whether the event should be ignored, retried, reversed, or escalated.

Repeated invalid transitions belong in Exception Management and monitoring because they can reveal ordering defects, replay, or inconsistent service ownership. Support staff should use approved corrective actions rather than forcing the state directly in the database.

State-transition controls should be shared across API, background workers, operator tools, and reconciliation jobs. If only the public API enforces the lifecycle, a support dashboard or repair script can still create impossible states. One domain service or database constraint should protect the authoritative transition, while higher-level interfaces request changes through audited commands.

Metrics should track transition rejection by source service and requested path. A sudden increase can reveal an ordering bug, stale client version, replay attack, or an incorrect recovery job before balances are affected.