This chapter supplies you with the basic knowledge about the following topics:

* [UI Extensions|#SOCref.DevelopersReferences.UIExtensions]
* [Overridable Components|#SOCref.DevelopersReferences.OverridableComponents]
* [Public Java APIs|#SOCref.DevelopersReferences.PublicJavaAPIs]
* [Java APIs sample code/ tutorial|#SOCref.DevelopersReferences.SampleCode/Tutorial]
* [Public REST APIs|#SOCref.DevelopersReferences.PublicREST_APIs]
* [Rest Service APIs|#SOCref.DevelopersReferences.RestService_APIs]
* [Public Javascript APIs|#SOCref.DevelopersReferences.PublicJavascriptAPIs]
* [Social JCR Structure|#SOCref.Social_JCR_Structure]

With this knowledge, you can extend more functions for eXo Social, or customize them as you want.