ButterCMS is SaaS so we host and maintain the CMS API and Dashboard. We integrate well with Salesforce applications and we've worked with many companies using Salesforce.
We've also partnered with Salesforce as an add-on in their Heroku marketplace: https://addons.heroku.com/butter/. You'd have an app on Heroku that can use the Salesforce Connector and also connects to Butter via our API.
If you'd like more information for Salesforce based architectures, please email support@buttercms.com.