Cisco provides partners with the full set of Collaboration APIs for applications hosted in a Cisco Webex Calling Dedicated Instance. This allows you to resolve complex integrations, develop custom solutions, and extend collaboration services for partners and customers.

https://www.cisco.com/c/dam/td-xml/en_us/voice-ip-comm/ucm_cloud/WebexCallingDI_Islands/Cisco_WxCDI_API_Provisioning_Guide.pdf