The Logging API shipped with Optimizely Content Management System (CMS) is an abstraction for writing log messages from the system, and is used internally by the CMS assemblies for all logging.

When creating new CMS sites using the [Visual Studio integration](🔗), the package _EPiServer.Logging.Log4Net_ is installed by default, which is the log4net implementation of the API. Optimizely Search & Navigation also uses the log4net framework.

## Activate logging

To activate logging, add an appender and a logger in the _EPiServerLog.config_, located by default in the web root of your CMS or Optimizely Customized Commerce application, for the `EPiServer.Find` namespace.



If your application does not have an _EPiServerLog.config_, create one in your application's web root folder and add the logger and appender there.



See also [Logging in Optimizely Content Management System (CMS)](🔗)