Heroku Enterprise is part of that toolset. It can enable you to build custom applications to facilitate amazing customer experiences. You might know that Force.com allows you to build employee-facing apps to customize and extend your Salesforce CRM.
With Heroku Enterprise you can go even further, building pixel-perfect applications for your customers in open-source languages like Java, Ruby, Python, PHP, JavaScript, and Go. You can go beyond the bounds of Force.com but stay connected to your data inside Salesforce. It’s basically the best of both worlds! Many customers are leveraging Heroku Enterprise for powerful web and mobile applications that drive increased customer engagement.
Why Heroku?
A PaaS abstracts away the complexity of building and running infrastructure for applications. Using a PaaS allows you to easily create load-balanced collections of containers that run your software. You can think of those containers just like shipping containers that hold all the code and resources needed to run your application.
Trailhead – https://trailhead.salesforce.com/modules/heroku_enterprise_baiscs/units/hello_heroku