A JSON File is a file containing JSON object and JSON Array. The JSON file is mainly used for exchange data from the server to web Application or Mobile Application.
it is a stander Data exchange format. JSON files are very lightweight, text-based, human-readable, easily editable with any text editor.
You can refer other below awesome post of JSON.
Refer Below Powerful and easy Tools for JSON Data.
You can compare JSON file, data, and URL on https://jsoncompare.org and https://jsondiff.org its best tool for comparing with details.
You can format your JSON file and URL and Data directly on https://jsonbeautifier.org and https://jsonparser.org/ – it is a very powerful and easy tool for view JSON data.
You can refer below post for JSON format example.