This article announces AWS Lambda's new Availability Zone metadata capability, enabling developers to determine which AZ their Lambda function is running in.

• Lambda functions can now retrieve AZ ID via new metadata endpoint
• Enables AZ-aware routing decisions to reduce cross-AZ latency
• Supports AZ-specific fault injection testing and resilience patterns
• Works with all Lambda runtimes, container images, SnapStart, and provisioned concurrency
• Available at no additional cost in all AWS Regions where Lambda operates
• Access via Powertools for AWS Lambda or direct HTTP requests

This feature simplifies building serverless applications that optimize performance by routing requests to same-AZ endpoints.