I am just going through this SharePoint 15 Training video and they are mentioning these terms again and again but am not sure with them though.
MSDN Video talking about Sharepoint APIs
I think the Server Side API means we use the Microsoft.SharePoint.dll while developing a solution for SharePoint or an application developed using this API will be on a sharepoint server and we can use SPWeb or SPSite objects if we can use this api.
I'm not sure by client side API though. What is the difference between these APIs and where can we use them?