DialogueBranch
DialogueBranch is our open-source toolkit for scripting and executing interactive conversations between computers and humans. It is a collection of software components, and a language definition that together provide the necessary tools for writing, storing, and executing scripted conversations in your application of choice.

Our dedicated website at www.dialoguebranch.com provides all the details about the platform, including detailed (technical) documentation on how to get started using this open-source technology.
Fruit Tree Labs maintains the DialogueBranch platform. If you wish to integrate in your application and need some help, we are available for hire.