On August 19, 2025, between 9:32 AM and 10:50 AM PDT, some customers experienced failures when calling PlayFab APIs due to issues with entity token validation. The incident was caused by a switch in the JSON library used for serialization and deserialization of entity tokens (for improved security and efficiency). We resolved the issue by rolling back the serialization change and advising impacted customers to refresh their tokens.

Impact

During the incident, calls to validate entity tokens failed, preventing all further API calls using those tokens. Affected APIs primarily included WriteTelemetryEvents, Catalog search, GetPlayFabIdFrom*Id, ExecuteCloudScript, and Group-related APIs. This resulted in service disruption for customers relying on these endpoints.

Root Cause Analysis

The root cause was a deployment that switched the JSON library responsible for entity token serialization. After rolling back the change, errors persisted for tokens minted during the incident window, requiring customers to refresh their tokens.

Action Items

To prevent similar incidents from happening again, we have taken the following actions:

• Added documentation to the entity token release process to highlight serialization risks and warnings.

• Implemented additional backcompat token tests for the entity token to expand test