What mechanism does Dynatrace use to track transactions in HTTP requests?

Dynatrace uses the x-dynatrace header to track transactions in HTTP requests. This mechanism enables the capture of detailed performance data and transaction tracing through the inclusion of a unique identifier in each HTTP request. When a request is made, the x-dynatrace header allows Dynatrace to associate that request with relevant details such as the end-user experience, backend processing, and more. This header plays a critical role in the distributed tracing capabilities of Dynatrace, allowing for an end-to-end view of transactions across various services and microservices.

The other options, while related to various aspects of monitoring and performance analysis, do not serve the specific function of transaction tracking in HTTP requests in the same comprehensive manner as the x-dynatrace header. For example, the dtdTraceTagInfo property pertains more to internal trace tagging rather than being a mechanism used widely in HTTP requests. Similarly, a unique message key may identify messages in certain systems but isn't specifically tied to HTTP request tracking. The app performance index typically aggregates performance metrics but doesn't track individual transactions through HTTP requests.