EMA C++ Developers Guide : 6 Consuming Data from the Cloud : 6.1 Overview
 
6.1 Overview
You can use the Enterprise Message API to consume data from a cloud-based LSEG Real-Time Advanced Distribution Server. The API interacts with cloud-based servers using the following workflows:
Credential Management (for details, refer to Section 6.3)
Service Discovery (for details, refer to Section 6.6)
Consuming Market Data (for details, refer to Section 6.7)
Login Reissue (for details, refer to Section 6.4.3)
There are two versions of login credentials for the Delivery Platform:
Version 1 Authentication also known as “V1 auth”, “OAuthPasswordGrant” or “V1 Password Credentials”: Uses the OAuth2.0 Password grant or Refresh Token grant. Requires a Machine Account consisting of username and password; also requires a client ID generated by the LSEG AppGenerator. For details, refer to Section 6.4.
Version 2 Authentication also known as “V2 auth”, “OAuthClientCredentials” or “V2 Client Credentials”: Uses OAuth2.0 Client Credentials grant to obtain an access token. Requires a Service Account consisting of client ID and client Secret. For details, refer to Section 6.5.
 
NOTE: Version 2 Authentication is available as an Early Access feature to API developers to preview changes required to use this new authentication mechanism. Please note that the ability to setup Service Accounts to use this authentication is forthcoming.
The Enterprise Transport API will determine which authentication version to use based on the inputs. By default, for cloud connections the Enterprise Message API connects to a server in the us-east-1 cloud location.
For further details on Real-Time as it functions in the cloud, refer to the Real-Time — Optimized: Installation and Configuration for Client Use. For details on the parameters you use to configure cloud connections, refer to the EMA C++ Edition Configuration Guide.