The Salesforce App Cloud is essentially a development environment built on the same platform as Salesforce Sales, Marketing and Service clouds.
It is comprised of three main components.
- Lightning Components
Force.com allows software developers to develop line of business applications on the same multi tenant Software as a Service platform as Sales, Marketing and Service Cloud applications reside. By building on Force.com developers remove the need to deploy hardware, operating systems and databases for their applications. They instead focus upon creating the fields, page views and workflows that solve a business problem.
Salesforce Developers use Visualforce to create custom page layouts and views and Apex to create custom software code. Apex is essentially a Java like programming language that runs in the Force.com environment.
Heroku is very much like Amazon Web Services. It is a cloud platform that allows developers to create software applications and deploy them on the Internet. Unlike Force.com, Heroku is a platform as a service that allows developers to deploy applications in various software languages and frameworks of their choice. For example it began as a Ruby On Rails In the Cloud. It since has expanded to support PHP, Java, Node, Python, Go,Scala, or Clojure.
Lightning is a new component based approach to user interfaces released in 2015 by Salesforce. Lightning components are built using an open-source Aura Framework. There is also support for Apex in Lightning. What does this mean? For developers it allows them an additional toolset to create stand alone apps, mobile apps in the context of Salesforce 1 Mobile, Lightning App Builder and Lightning Process Builder.
The promise of Lightning is to replace the look and feel of Salesforce Classic user interface and to allow less technical users to create their own app views. Realistically it has many complexities that probably make it impractical for a non-developer resource to deploy applications. Our experience so far is that you still need developers to Lightning build apps, developers with the ability to understand HTML5, Apex code and CSS.