What is json?

JSON (JavaScript Object Notation) is a lightweight text format used to store and exchange data. It looks like a collection of name‑value pairs, similar to how you would write a list of items in a notebook. Because it is plain text, both humans and computers can read and write it easily.

Let's break it down

  • Objects: Curly braces { } hold a set of key‑value pairs, e.g., {"name":"Alice"}.
  • Arrays: Square brackets [ ] hold an ordered list of values, e.g., [“red”,“green”,“blue”].
  • Values: Can be strings (“text”), numbers (123), booleans (true/false), null, objects, or arrays.
  • Syntax rules: Keys must be quoted strings, items are separated by commas, and there are no comments.

Why does it matter?

JSON provides a simple, language‑independent way to move data between programs, especially web browsers and servers. Its readability makes debugging easier, and its compact size speeds up network communication.

Where is it used?

  • Web APIs that send data to front‑end apps (e.g., fetching weather info).
  • Configuration files for tools and services.
  • Storing data in NoSQL databases like MongoDB.
  • Communication between microservices in cloud applications.
  • Mobile apps syncing with back‑end servers.

Good things about it

  • Easy to read and write for humans.
  • Supported natively by most programming languages.
  • Small file size compared to XML, leading to faster transfers.
  • Strict syntax reduces ambiguity.
  • Works well with JavaScript, the language of the web.

Not-so-good things

  • No support for comments, making it harder to annotate files.
  • Only a limited set of data types (no dates, binary data, etc. without custom handling).
  • Strict syntax can cause errors if a single comma or quote is misplaced.
  • Not ideal for very large or complex hierarchical data where a binary format might be more efficient.