The VersionOne Integration Platform is an open-source toolkit for building applications that integrate with the VersionOne Application.  This platform is illustrated in the diagram below

 

 

From this diagram we observe that an external application or integration can interact with the VersionOne server using one of the following methods

We also see that each layer builds on the previous layer.  The higher layers make development simpler and faster, but with that simplification comes a loss of power/expressiveness.   Most projects should only need the Object Model Library, but there is the ability to 'drop down' to using the APIClient directly for more advanced capabilities - and there's always the option to work directly against the API.

 

How to determine which level to develop against?

 

In order to determine which entry point to use, you first need to determine your development language.  If you are not developing in C# or Java you need to use the Core API. 

 

Developers using Java need to use the Legacy APIClient. (this is a temporary solution until the Java SDK is complete)

 

Developers using C# need to consider the server build version.  If the server build version is not 8.0.1197 or better, you need to use the Legacy APIClient Libraries.

 

Developers using C#, with a server build version of 8.0.1197 or better need to consider the type of application being developed.  If you are developing an integration with another system or a utility application, consider using the Object Model Library first.  If you are developing a reporting application, have a need for complex query/filtering, or you have an application that would benefit from server side ordering, the new APIClient , which is contained within the SDK download, is better suited for your needs.