Note: [Deprecated Content] This was written while ASP.NET and .NET Core was in beta (around beta5 or beta6). Since then a lot of stuffs have changed and moved around. Stuffs described below may or may not be true for current stable releases of ASP.NET Core. I recommend not to follow along and get confused. Use official configuration documentation that explains it correctly - Along with the new version ASP.NET 5, comes some small goodies that are worth taking look at. One of those tiny but powerful enhancment currently experimented in ASP.NET 5 (still in BETA at the time of writing, may change) is the way to control exception / error detail displayed to end user and showing full stack trace and additional information when the developer is working. If you have given a try to the default template - "ASP.NET 5 Starter Web" » Read more