DOTNETENVIRONMENT

DOTNET_ENVIRONMENT is an environment variable used by the .NET runtime and hosting infrastructure to designate the environment in which an application is running. The value exposed by this variable is typically exposed to the app as IHostEnvironment.EnvironmentName, influencing how configuration and behavior are applied during startup and execution.

This environment name governs loading of environment-specific configuration files, such as appsettings.{EnvironmentName}.json, and can affect code paths that check the current environment (for example, by using IsDevelopment, IsStaging, or IsProduction helpers). While the most common, conventional names are Development, Staging, and Production, any string can be used, though using the standard names improves compatibility with framework helpers and templates.

In practice, ASP.NET Core projects often rely on a related variable, ASPNETCORE_ENVIRONMENT, to set the environment for web hosting. For non-web or generic host applications, DOTNET_ENVIRONMENT commonly serves this purpose. If both variables are defined, the exact precedence can depend on the hosting scenario and framework version; web apps typically rely on ASPNETCORE_ENVIRONMENT, while other hosts may read DOTNET_ENVIRONMENT.

How to set and use

- Windows (PowerShell): $env:DOTNET_ENVIRONMENT = "Development"

- Windows (cmd): set DOTNET_ENVIRONMENT=Development

- Linux/macOS: export DOTNET_ENVIRONMENT=Development

Impact and defaults

If DOTNET_ENVIRONMENT is not set, the default environment name is Production. Changing the value affects configuration loading, logging behavior, and environment-dependent code paths, making it a common tool for switching between development, testing, and production-like settings without recompiling.