How JSON.stringify() Works in JavaScript

JSON.stringify() is Javascript built-in method that converts Javascript object or value into JSON string.

The syntax of JSON.stringify is
JSON.stringify(value, replacer, space)

Parameters:

• value – The object or value to convert.
• replacer (optional) – A function or array that filters properties.
• space (optional) – Adds indentation, spaces, or line breaks for readability.

Why Do We Use JSON.stringify()?

• To send data to APIs - Most APIs expect data in JSON format.
• To store data - When saving object in localstorage or database, they must be string.
• To debug easily - It’s helpful to see object structures as strings.

Real-World Use Case

fetch("/api/save", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({ name: "David", email: "[e-mail]" })
})