Difference between Setting.settings and web.config?

Web.config is mostly meant for configuration, and it also stores the default values of your settings.

Settings.settings is just a convenience file for Visual Studio to provide a UI for editing your settings.

The .config comes in two different flavors: App.config for Windows applications, which will be named YourApplication.exe.config, and the Web.config for web applications. They share the same schema, syntax, and options.

• You may notice that if you add a setting to Settings.settings, it gets added to the .config as well.
• The .config must be deployed with apps, but Settings.settings doesn't need to.