RingCentral offers communication services like VoIP calling, web meetings, and fax through a secure cloud phone system. Creating RingCentral applications is easy and can be done within minutes by logging into the RingCentral developer account. Once created, applications can access RingCentral APIs based on permissions and features. The RingCentral API uses specific error codes to simplify error processing for client applications. There are different categories of errors like server errors (HTTP 50x), authentication errors (HTTP 40x), and rate limiting errors (HTTP 429).