BSc IT - Web Application Development - ASP.NET

The web.config  file is a configuration file  in ASP.NET that stores settings for the application. 
It is used to: 

    Set connection strings  (for database access).
    Configure application settings  (like keys, values).
    Define security settings  (authentication, authorization).
    Handle error pages , debugging, and custom settings.
    No need to recompile when you change it (auto-detected).