dot Net

launchSettings.json

Location: Properties/launchSettings.json

Purpose: Development-time launch configuration. Defines how the app runs when you launch it from Visual Studio, Rider, or dotnet run — including which URL, environment, and browser to use.

Example:

{
  "profiles": {
    "MyWebApp": {
      "commandName": "Project",
      "dotnetRunMessages": true,
      "launchBrowser": true,
      "launchUrl": "swagger",
      "applicationUrl": "http://localhost:5000;https://localhost:5001",
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development"
      }
    }
  }
}

Key facts:

• Used only by development tools.
• Controls launch-time settings, not production behaviour.
• Ignored when you publish/deploy your app (unless you explicitly export values).
• Commonly defines:
  • Port numbers (applicationUrl)
  • Whether to open a browser
  • Environment (ASPNETCORE_ENVIRONMENT)
  • Which command (Project, IISExpress, etc.)

appsettings.json

Location:
Root of the project (same folder as Program.cs).

Purpose:
Defines your app’s configuration values — connection strings, logging, custom settings, API keys, etc.

Example:

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft": "Warning"
    }
  },
  "ConnectionStrings": {
    "DefaultConnection": "Server=myServer;Database=myDb;User Id=myUser;Password=myPass;"
  },
  "AllowedHosts": "*"
}