You will find this file in the “Properties” folder in the project root folder.
The settings in this file are used when we run this ASP.NET core project either from Visual Studio or by using .NET Core CLI.
This file is only used on local development machine. We do not need it for publishing our asp.net core application.
If there are certain settings that you want your asp.net core application to use when you publish and deploy your app, store them in appsettings.json file. We usually store our application configuration settings in this file.
We can also have environment specific appsettings.json files. For example, appsettings.Staging.json for the staging environment. In ASP.NET Core, in addition to appsettings.json file, we also have other configuration sources like Environment variables, User Secrets, Command Line Arguments and even our own custom configuration source.**

In ASP.NET Core, the launchSettings.json file is a configuration file used during development to define how the application should be launched and debugged. It provides settings for various launch profiles, allowing developers to specify different configurations for different environments and scenarios.

Here are some key points about the launchSettings.json file:

Development tool integration: The launchSettings.json file is used by development tools like Visual Studio or the .NET CLI to determine how the application should be launched and debugged during development.

Multiple profiles: The file supports multiple profiles, each representing a specific way to launch or debug the application. For example, you can have profiles for different environments like “Development,” “Staging,” or “Production,” or profiles for specific scenarios like running tests or launching the application with specific command-line arguments.

Configuration options: The launchSettings.json file allows you to configure various options for each profile, such as the application URL, environment variables, command-line arguments, and more. These settings help customize the development experience based on the specific requirements of the profile.

Debugging settings: The file includes options for configuring the debugging experience, such as the type of debugger to use, launching the browser, attaching to a running process, and other debugging-related settings. These settings help streamline the debugging process and provide a tailored debugging experience.

Profiles synchronization: The launchSettings.json file is typically stored in the project’s Properties folder and can be shared among team members through source control. This allows everyone on the team to have consistent launch profiles and settings, ensuring a unified development experience across different environments.

By utilizing the launchSettings.json file, developers can easily configure and manage different launch profiles for their ASP.NET Core application. They can define various settings such as URLs, environment variables, command-line arguments, and debugging preferences, enabling a customized and streamlined development and debugging process.