When building a Next.js application, it's important to organize your files and folders in a way that makes sense for your project's needs.

These folders are required by Next.js:

pages: This folder is the heart of your Next.js application and should contain all the pages of your app. Each page should be a React component that is automatically served as an HTML page when requested.

The pages/api folder should contain JavaScript files that export default functions which handle API requests. These functions should be defined with req and res parameters, which represent the HTTP request and response objects.

public: This folder should contain all the static files like images, fonts, and other assets that you want to be publicly accessible. These files are served as-is without any processing by Next.js.

styles: This folder should contain all the global styles and CSS files for your project. You can use this folder to organize your styles by functionality or feature. I generally use Tailwind CSS for styling my projects, but you can use any CSS framework or library you like.

node_modules: This folder should contain all the dependencies for your project. You should never need to edit the files in this folder, and you should never commit it to your version control system.

The following folders are optional and can be added to your project as needed:

components: This folder should contain reusable UI components that are used across different pages. It's a good idea to organize your components into subfolders based on their functionality, such as buttons, cards, forms, etc.

lib: This folder should contain any utility functions or reusable code that are not specific to a particular component or page. For example, you could put any custom hooks or API clients in this folder.

utils: This folder could contain any utility functions or helper methods that your application might need. For example, you could create a date-utils.js file that exports functions for working with dates.

config: This folder could contain any configuration files for your project, like environment variables or configuration settings.

tests: This folder could contain all your test files and related assets. You can use this folder to organize your tests by functionality or feature.

docs: This folder could contain any project documentation, like README files or design documents.

data: This folder could contain any data files that your application needs to run. For example, you could put a JSON file in this folder that contains a list of products.

By organizing your files and folders in this way, you can keep your codebase clean and modular, which makes it easier to maintain and scale your application over time.