CSOM (Client Side Object Model) is a web services-based API of SharePoint allowing easy remote access to data and SharePoint's functions.

CSOM, which stands for Client-Side Object Model, is a web services-based API of SharePoint. It allows access to SharePoint data and features from remote clients. CSOM was introduced in SharePoint 2010 and greatly enhanced in SharePoint 2013.

Both JavaScript and.NET bindings to CSOM exist. Software leveraging CSOM can integrate with SharePoint without the need to run within a SharePoint farm.

In SharePoint 2013 CSOM is the only API available to software built using the new Apps for SharePoint architecture. Apps for SharePoint run side-by-side, typically in the cloud, and integrate with both cloud and on-premise SharePoint farms.

Corresponding MSDN documentation is located here, with separate JavaScript and.NET API references. The web services-based API underlying CSOM has been documented as part of Microsoft's Open Specifications initiative.