How to change default port no of my .NET core 6 API

The port is defined in the endpoints and there are multiple ways to change them:

For Development purposes

You can change in launchSettings.json file inside Properties folder:

{
  "iisSettings": {
    "windowsAuthentication": false,
    "anonymousAuthentication": true,
    "iisExpress": {
      "applicationUrl": "http://localhost:22963",
      "sslPort": 44349
    }
  },
  "profiles": {
    "UrlTest": {
      "commandName": "Project",
      "dotnetRunMessages": true,
      "launchBrowser": true,
      "applicationUrl": "https://localhost:7244;http://localhost:5053",
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development"
      }
    },
    "IIS Express": {
      "commandName": "IISExpress",
      "launchBrowser": true,
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development"
      }
    }
  }
}

Server Endpoints

There is a file in root folder called appsettings.json with you can change the server related configuration, this is an example with Kestrel:

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },
  "AllowedHosts": "*",
  "Kestrel": {
    "Endpoints": {
      "Http": {
        "Url": "http://localhost:5400"
      },
      "Https": {
        "Url": "https://localhost:5401"
      }
    }
  }
}

From command line

You can run the application with the --urls parameter to specify the ports:

dotnet run --urls http://localhost:8076

Environment Variable

You can set the ASPNETCORE_URLS.

From source code

You can pass the Url to Run method:

var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();

app.MapGet("/", () => "Hello World!");

app.Run("http://localhost:6054");

Or the UseUrl extension method, but at the current time this is not working due the bug #38185:

var builder = WebApplication.CreateBuilder(args);
builder.WebHost.UseUrls("http://localhost:3045");
var app = builder.Build();

app.MapGet("/", () => "Hello World!");

app.Run();

Source:

https://docs.microsoft.com/en-us/aspnet/core/fundamentals/servers/kestrel/endpoints?view=aspnetcore-6.0

A good documentation about the deploy: https://docs.microsoft.com/en-us/aspnet/core/host-and-deploy/?view=aspnetcore-6.0

Quick solution:

if (app.Environment.IsDevelopment())
{
    app.Run();
}
else
{
    app.Run("http://127.0.0.1:8080");
}

You can set it from the launch profile setting

Click on the Dropdown on the run button.

Now click on debug properties. By clicking on that launch profile window will open.

now you can change the port from the app URL from here.

Edit: Add on

You can also change it from the project profile as below.