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NeatUtility

JSON Formatter

JSON & Data100% Client-Side
Ready
JSON
0 lines0 chars
0 B / 4.77 MB
About this tool, examples & FAQ

Parse valid JSON and serialize it with the indentation you choose, entirely in your browser. String contents keep their own spaces, and invalid JSON produces an actionable syntax error with line and column.

Key facts

Verified capabilities and limits of this utility
Accepted inputJSON text: objects, arrays, strings, numbers, booleans, or null
Indentation2 spaces, 4 spaces, or tab, with optional recursive key sorting
Max input size5 MB
Execution deadline2 s
Processing locationBrowser-only: pasted input is not uploaded

How to use

  1. Paste your raw JSON string into the left editor pane.
  2. Choose your preferred indentation: 2 spaces, 4 spaces, or Tab.
  3. Optionally enable 'Sort Keys' to alphabetize object keys recursively.
  4. Click 'Run' or press Ctrl+Enter to format your JSON.
  5. Use 'Copy' or 'Download' to retrieve the formatted output, or use 'Send To' to pipe into another utility like Base64 or YAML.

Examples

Format compact JSON

Input

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

Example output

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

Malformed JSON error

Input

{"ready":true,}

Example error

Expected double-quoted property name in JSON at position 14 (line 1 column 15)

Edge cases

Number precision

Values follow standard JavaScript JSON precision: integers beyond 2^53 - 1 may lose least-significant digits, and out-of-range literals such as 1e999 do not survive the round trip.

Duplicate keys

Duplicate object keys are not reported: the last value wins during parsing, matching JSON.parse behavior.

Key sorting order

Key sorting uses plain code-unit order, not locale-aware collation, so uppercase letters sort before lowercase ones.

How it works

  1. Parses the input with the platform JSON parser.
  2. Sorts object keys recursively when the option is enabled.
  3. Serializes the value with 2-space, 4-space, or tab indentation.
  4. Executes inside a Web Worker bounded by the tool deadline.

Related workflows

Frequently asked questions

What is the difference between the formatter and the validator?

The formatter rewrites valid JSON with readable indentation; the validator only decides whether the syntax parses and explains the first error. Use the formatter to clean up API responses and the validator to diagnose why parsing fails.

Why does formatting fail?

Formatting fails when the input is not valid JSON — for example trailing commas, single quotes, comments, or unclosed braces. The error message reports the line and column where parsing stopped.

Which indentation should I choose?

Choose 2 spaces for compact readability, 4 spaces for deeply nested documents, or tabs where your project style requires them. The choice only affects whitespace, never the data.

Are spaces inside strings changed?

No. Whitespace inside string values is preserved exactly; only structural whitespace between tokens is rewritten.

Are there size or precision limits?

Inputs are bounded by the documented input size, and numbers follow standard JavaScript JSON precision — integers beyond 2^53 - 1 may lose precision.

Is my JSON data uploaded anywhere?

No. Formatting runs inside an isolated Web Worker in your browser, and pasted input is not uploaded for processing. The browser still requests site assets from the host; clipboard, downloads, and analytics are separate boundaries.

References