Developer

JSON Formatter

Paste JSON and get a clean, pretty-printed version instantly — live validation with the exact error line and column, 2-space, 4-space, or tab indentation, and optional alphabetical key sorting. All in your browser.

Published May 20, 2026
Last reviewed July 9, 2026

Tool Summary Answer Block

This tool accepts structured input and returns deterministic output in the browser with no server upload.

Tool name: JSON Formatter
Input intent: Provide source content to transform, validate, or analyze.
Output intent: Receive normalized output suitable for copy, reuse, or debugging.
Example input: {"b":1,"a":{"y":true,"x":null}}
Example output: { "b": 1, "a": { "y": true, "x": null } }

Sort keys A→Z

0characters

InputDrop file

OutputRead-only

Paste JSON to format it live — the output updates as you type.

Need it on one line instead? JSON Minifier

Tool Introduction

Tool Overview

The JSON Formatter parses your input with the browser's native JSON engine and re-serializes it with the indentation you choose, so the output is always syntactically valid — never a cosmetic re-spacing of broken input. Formatting happens live as you type: a green badge confirms valid JSON, and invalid input shows the parser's error message translated to an exact line and column so you can jump straight to the problem, even in a large payload. Turn on key sorting to alphabetize every object at every depth, which makes diffs between two API responses dramatically easier to read. The result can be copied or downloaded as a .json file, and a shareable URL hash preserves your input so you can send a colleague the exact document you are looking at. Everything runs client-side; your JSON never leaves your device.

Use Cases

Inspect a minified API response or log line without squinting at one endless row
Validate JSON before committing a config file, with the error line pinpointed when it fails
Sort keys alphabetically so two versions of a payload diff cleanly
Re-indent JSON to match a project's 4-space or tab style before a pull request
Share a formatted payload with a teammate via the URL, which keeps your input in the hash

Input/Output Examples

Default 2-space indentation; turn on Sort keys to emit "a" before "b".

Input Intent

{"b":1,"a":{"y":true,"x":null}}

Output Intent

{
  "b": 1,
  "a": {
    "y": true,
    "x": null
  }
}

Errors report the exact line and column instead of a bare "Invalid JSON".

Input Intent

{"a": 1, "b" 2}

Output Intent

Line 1, column 16: Expected ':' after property name

FAQ

Is my JSON sent to a server?+

No. Parsing and formatting run entirely in your browser using the native JSON engine, so payloads with tokens or personal data never leave your device.

How do I find what's wrong with invalid JSON?+

The error message under the input includes the exact line and column where the parser stopped — typically a missing comma, an unquoted key, a trailing comma, or single quotes instead of double quotes.

Can I change the indentation level?+

Yes. Switch between 2 spaces (the JSON ecosystem default), 4 spaces, and tabs — the output reformats instantly.

What does Sort keys do?+

It alphabetizes the keys of every object at every depth before formatting. Arrays keep their order, since reordering array elements would change the data's meaning.

Does formatting change my data?+

No. Only whitespace (and key order, if you enable sorting) changes. Values, strings, and numbers are re-emitted exactly as the JSON standard defines them.

Can it handle comments or trailing commas?+

No — those are JSON5/JSONC extensions, not standard JSON. The formatter follows the strict spec, which is what APIs and config parsers expect.