JSON is a format for data storage and sharing. There are other formats but JSON is easily written and read using JavaScript and transported via web services. The importance of it comes from it being a "standard" that all developers know.
JSON files are basically XML files that run better in browsers, but they are still different. XML can be a bit more specific, but more intensive.
JSON type files are a way of serialization. This means the file condenses for easy downloads/uploads, transmits to another location, and then is interpreted primarily by web browsers.
So, primary purpose is to be able to be functional, compressible, easily loadable and still interpretable, while in that compressed state.
JSON is actually kind of different language from JS, but it is still very much the same. But you will have some trouble if you code the two exactly alike without a translator of some sort, as far as I know.
Well, JSON is the abbreviation for "JavaScript Object Notation". It is a text-format, representing a subset of JS which is useful for storing information in an ordered fashion. It is very simple to use, and since it is JS, any JS interpreter can simply interpret it, which makes it ideal for web apps (any browser can interpret JS, right?) Another important fact is, that it is very easy to read as a human (in contrast to binary formats). Its simplicity allaround has made it the #1 format for web data exchange.
Alternative formats could be XML (which was very popular before JSON and still is important in anything .NET), YAML (which is quite important in the Java world), TOML (which is widely used in the Rust world) and many more. You should choose your format based on your requirements; for example if you have a lot of table data and work with Excel, but want to display the data in some web-app at some point, csv might be a better choice.
JSON is a way to store / transmit (potentially) complex data structures easily. It's essentially a few primitive data types (null, booleans, integers, floats and text) as well as a list (usable for set/tuple/list/array/...) and map (usable for objects or maps).
There are countless ways to store / transmit such data structures, but the only one with similar prevalence is XML. XML used to be the de-facto way to do this, but these days JSON is the go-to choice. There are some differences (XML has attributes), but in many cases, either one will do (and it isn't uncommon for both to be supported).
Umesh Kumar
easy to read, lightweight. alternatives are xml , yaml (json with comments)