When articles are transmitted through web services using only their message body, they often lack the information required for thorough and reliable analysis. For security-related use cases, it is often necessary to send the complete raw email, including all message headers, so that remote systems can perform more comprehensive analysis.
To support this, OTRS provides the ability to send the complete raw email source through the generic interface using web service operations and invokers.
Provider Configuration
Then if OTRS is configured as the provider, the raw article source is sent automatically once the web service is configured. This functionality is available only for the TicketGet operation.
Requester Configuration
When OTRS is configured as the requester, the raw article source must be explicitly enabled in the invoker configuration by selecting the ArticlePlain field.

The ArticlePlain field is supported by the TicketCreate and TicketUpdate invokers.
Viewing the Raw Article Source
The raw article source is included in the web service communication payload. For testing and troubleshooting purposes, it can also be viewed in the web service debugger.
