JSON Formatter

Values and structure

A JSON document contains one value. That value can be an object or array, but a string, number, boolean, or null is also valid at the root. Objects associate string names with values; arrays contain values in a meaningful sequence. Both can be nested.

The syntax to get right

Use double quotes for property names and strings. A colon separates a name from its value; commas separate object members and array items. Do not add a comma after the last member or item. Comments, single quotes, and JavaScript expressions are outside strict JSON.

The literals true, false, and null are lowercase. Numbers use decimal notation with an optional minus sign, fraction, and exponent. Leading zeros, a leading plus sign, NaN, and Infinity are invalid. Within strings, escape quotation marks, backslashes, and control characters; a newline must be written as an escape such as \n.

Object names should be unique for reliable interchange. Different consumers may keep different values when names repeat. The formatter reports duplicates and preserves them so you can decide how to resolve them. A syntax check alone cannot confirm that a document matches an API contract or JSON Schema.

What formatting preserves

DevToolsy validates the input and adjusts whitespace around its original tokens. It retains number text such as 900719925474099312345, 19.9900, 1e+400, and -0, along with the original string escapes. This avoids rounding caused by parsing and reserializing numbers as JavaScript floating-point values. The application that reads the result still determines its own numeric precision.

Indentation, LF or CRLF line endings, and a final newline are output conventions. Sort keys is a separate, optional change: it recursively orders object members by decoded names using a deterministic, case-sensitive comparison. Array order and the relative order of duplicate names stay intact. This is for reading and diffs; it is not a canonicalization scheme for cryptographic signatures.

{"name":"Ada","roles":["developer","reviewer"],"active":true}

{
  "name": "Ada",
  "roles": [
    "developer",
    "reviewer"
  ],
  "active": true
}