You can find your Sandbox Account credentials by following here. RingCentral Sandbox Accounts use real telephone numbers, this is why we only allow one Sandbox Account per developer organization.
To configure your Sandbox Account (i.e. create extra extensions, add telephone numbers, etc.), please use the Sandbox version of our servise web site: https://service.devtest.ringcentral.com (and use your Sandbox credentials to log in).
In order to send API in the sandbox environment ( https://platform.devtest.ringcentral.com), requests towards Sandbox environment, you will need to authenticate using:
- Sandbox Account Main Company Number as a username (in 1xxxxxxxxxx format)
- Sandbox Account password, which had been sent to the developer who had initially created the account
- Sandbox Application Key and Secret, which can be found on your apps basic information page: see here