RingCentral provides a sandbox environment for developers to test and build applications using its APIs. The summary outlines 5 steps to set up a RingCentral sandbox account: 1) Get a developer account on the RingCentral developer portal. 2) Log into the developer account and locate the sandbox account details. 3) Set the password for the sandbox account and log into the online account portal. 4) Create a test application on the developer dashboard by selecting the platform and feature to access via APIs. 5) The application API key and secret can then be used to test the application using the RingCentral APIs.