# Request Correlation ID
source: https://developer.mastercard.com/mastercard-processing-core/documentation/api-basics-section/request-correlation-id/index.md

Correlation ID, also known as Transit ID or Request ID, is a unique identifier value attached to a particular transaction or event chain. The `Correlation-Id` header also helps in auditing, debugging, and tracing the request execution flow.

It is recommended to generate a universally unique identifier (UUID) in compliance with [RFC 4122](https://datatracker.ietf.org/doc/html/rfc4122).

In addition, Mastercard edge devices inject `X-MC-Correlation-ID` header to each request, and it is also added to the response header to provide end-to-end traceability.