I am trying to consume a REST API which is hosted on AWS from a UI developed on OutSystems. This REST API requires AWS Signature as part of the request, how does Outsystems sign the request message going out AWS.

Hi Prasad

Sorry for the late answer. When consuming a REST API you can use the advanced extensibility (OnBeforeRequestAdvanced) where you can add an extension from IntegrationStudio and directly access the HTTPRequestContext object in order to create the signature.

Read more about it here: https://success.outsystems.com/Documentation/10/Reference/OutSystems_APIs/REST_Extensibility_API_for_.Net