To be able to talk to Salesforce from RINT we need to setup a connected app in Salesforce and the user that will access the API.

Add Connected App

Login to Salesforce (we used the https://login.salesforce.com)
Click the Cog then Setup you will end up on the page .../lightning/setup/NavigationMenus/home
Expand
title Click here to show image...
Under section Platform Tools → Expand Apps and click on App Manager
Expand
title Click here to show image...
Click New Connected App button
Enter
Connected App Name
API Name
Contact Email
Check the Enable OAuth Settings
Enter the callback url. This is the url found on the Authentication page in RINT when creating a new OAuth.
Or enter manually <baseUrl>/secure/RestfulClientAction.jspa
In the Selected OAuth Scopes select the access level, in our example we will use Full access (full) and Perform requests on your behalf at any time (refresh_token, offline_access)
Note. Must
have Perform
have Perform requests on your behalf at any time (refresh_token, offline_access) to make it a refresh token, otherwise the connection dies.
Expand
title Click here to show image...
Click Save

Set the Permission Set

Make sure the API user has enough permission, here is an example of adding a new permission set and adding that to a user.

Under section Platform Tools → Expand Users
Click New (or reuse existing, don´t click new view)
Enter a name such as API
Click System Permissions
Check API Enabled and Apex REST Services
Expand
title Click here to show image...
Click on Users
Click on the user that you will use for API access
Scroll down to Permission Set and edit. Assign the new API permission set to the user
Save and all done!
Expand
title Click here to show image...