Goodkind connects to Salesforce via the Connected apps framework. The account used for connection can be an admin account or an integration user. The following permissions are required for the connection.
Most of these permissions are found under the Administrative Permissions section. (Salesforce help article is linked).
Admin user
Reading data from Salesforce
Access to public reports
Read access to contacts, opportunity objects
Bulk read data
Writing data back into Salesforce
Field level security to write data into fields for Task Sub object within Activity Object
"Edit tasks"
"View and Setup Configuration"
For Integration user
Reading data from Salesforce
Using the "Salesforce API Only System Integrations" Profile
Assigning the "Salesforce API Integration" under "Permission Set License Assignments"
read access to contacts, opportunity objects
Using Role Hierarchy with a "Admin" role to allow access to records owned by sub roles
Writing data back into Salesforce
Field level security to write data into fields for Task Sub object within Activity Object
"Edit tasks"
"View and Setup Configuration"