JSON files, which bear the extension .json, are a type of file used to store simple data structures and objects in JavaScript Object Notation (JSON) format. They are widely used in web applications for data interchange between a server and a client. However, many people may encounter difficulties when trying to open these files as they are not directly editable like text files without using the right tools. Here’s your guide to opening JSON files on both Windows and Mac computers.

On Windows:

1. Notepad: Every Windows computer comes with Notepad, a basic text editor that can open JSON files. To open a JSON file in Notepad, right-click on the file, select “Open with,” and then choose “Notepad.” However, while Notepad can open and display JSON files, it does not format them or highlight syntax, which can make it challenging to read complex JSON data.

2. Notepad++: A more advanced textual content editor for Windows is Notepad++. It offers syntax highlighting for various file types including JSON. After installing Notepad++, you can open a JSON file by right-clicking it, selecting “Open with,” and choosing “Notepad++.” This makes it easier to navigate and edit the JSON structure.

3. JSON Viewer: Another tool is JSON Viewer which provides a tree view of your JSON data that can be expanded and collapsed helping you to understand the structure of your JSON data. To use this tool, you would need to download and install it first, then you can open your .json file with it.

4. Visual Studio Code: VS Code is a highly customizable code editor from Microsoft that supports numerous programming languages including JSON. Once installed, simply open VS Code, go to File > Open File, and select your JSON file. It will not only display the contents but also provide syntax highlighting and auto-formatting features for better readability.

On Mac:

1. TextEdit: Just like Windows has Notepad, Mac OS comes with TextEdit which can be used to view and edit plain text files including JSON files. To open a .json file with TextEdit, right-click (or control+click) on the file in Finder, select “Open With,” then choose TextEdit from the list.

2. Sublime Text: This is another powerful editor that’s available for Mac users which supports syntax highlighting for a large array of programming languages including JSON. Install Sublime Text and then right-click on your .json file and choose Sublime Text from the “Open With” menu.

3. Visual Studio Code for Mac: Just as on Windows, Visual Studio Code works well on Mac too for editing JSON files with additional features like linting and automatic formatting that make working with JSON even easier.

4. MacOS Terminal: Advanced users may opt to use command line tools such as ‘cat’ or ‘more’ in terminal to view the contents of their .json files directly within Terminal or use ‘vim’ or ‘nano’ if they wish to edit their .json files via command line interface.

While these are some common tools that can be used to open .json files across both Windows and Mac platforms, there are many other web-based utilities available that will format and display .json documents within your browser without needing any special software installed on your computer.

Remember that though all these tools can be used to open and display .json files, always be cautious when editing any system-related or configuration .json files as mistaken alterations could lead to issues within the applications that rely on them.