CData Connect Cloud offers a pure cloud-to-cloud interface for your data, enabling the creation of business applications directly from live data within Appsmith. In Connect Cloud, you can create connections from 300+ sources, and then connect to that data in Appsmith using Connect Cloud’s Virtual SQL Server. 

The article below outlines the process of connecting to a data source in Connect Cloud and creating a basic application from that data within Appsmith:

https://www.cdata.com/kb/tech/salesforce-cloud-appsmith.rst
Note: While this article refers to Salesforce, the principles can be applied to any of the 300+ data sources CData Connect Cloud supports.