CloudFiles is fully supported in Salesforce professional edtion. You don't have to buy the API add-on too. However, some automation capabilities which are available in the Salesforce Enteprise edition are not available in Professional edition.

How to install

1. Install the latest version of CloudFiles in Salesforce professional edition from this link - https://login.salesforce.com/packaging/installPackage.apexp?p0=04t5g000000m6r0AAA This vesion is security reviewed by Salesforce. However, we have not listed this version on AppExchange in favour of listing the Enterprise edition version. If you're using Salesforce Enterprise edition or above, please install CloudFiles from CloudFiles listing on the Salesforce App Exchange
2. For rest of the installation process, please follow the Installation guide same as Enterprise edition version

For any help, please feel free to reach out to us using live chat or email us at support@cloudfiles.io