Where could i lookup my AccountID and ExtensionID

The best way to get your Account ID after you've received an access_token is to use send a GET request to /restapi/v1.0/account/~

This will return the account information for the authenticated user. Here are the docs: https://developers.ringcentral.com/api-docs/latest/index.html#!#RefAccountInfo.html


The best way to get your Extension ID after you've received an access_token is to send a GET request to /restapi/v1.0/account/~/extension/~

This will return the extension information for the authenticated user. Here are the docs: https://developers.ringcentral.com/api-docs/latest/index.html#!#RefGetExtensionInfo

And by the way send a GET request to /restapi/v1.0/account/~/extension to get a list of the extensions in your account.