# Use of the REST API
This article describes the steps required for a third-party application to access the ELO Sync REST API.
This requires the application to be registered in Azure.
Information
In general, no specific server-side errors are returned via the REST API for security reasons. You will find the detailed errors in the server log file.
# Authentication with Azure
Unlike authentication via the interface, which is done through the OpenIdConnect endpoint, access via the REST API requires a bearer token.
The authentication process for generating a token varies depending on the application type and programming language or framework used. You will find an overview here: Microsoft identity platform code samples for authentication and authorization (opens new window)