JSON Formatter

Format, validate, and beautify your JSON data with advanced comparison features, syntax highlighting, and professional-grade tools.

Mode:

Indent:

Input JSON

Output

Formatted JSON will appear here

Overview

JSON Formatter, Validator & Diff Tool

The JSON Formatter on sourcecodestack parses, formats, and validates JSON data entirely inside your browser — no server receives your data at any point. Paste raw or minified JSON and click Format to instantly produce clean, consistently indented output. The built-in validator reports the exact parse error and line offset when your JSON contains a syntax mistake, so you can fix issues without guessing.

Beyond single-document formatting, the tool includes a side-by-side JSON diff mode. Paste two JSON objects and click Compare to see a Git-style diff: added keys are highlighted in green, removed keys in red, and modified values in yellow. You can adjust the indent size between 2 spaces, 4 spaces, or tab-style output, and copy any result to your clipboard with one click.

100% freeNo sign-upRuns in your browserNothing uploaded

How to use it

1Paste your JSON into the Input JSON textarea on the left.
2Choose Format, Validate, or Minify — the result appears in the Output panel on the right.
3To compare two objects, switch to Compare JSON mode, paste a second document, then click Compare.
4Adjust the Indent selector (2 spaces / 4 spaces / 1 tab) before formatting to match your codebase style.
5Click the copy icon on any panel to copy the content to your clipboard.

Key features

Pretty-print JSON with configurable indent: 2 spaces, 4 spaces, or tab

Strict validation with precise error messages showing the position of the syntax fault

One-click minification strips all whitespace for compact payloads

Side-by-side JSON diff with colour-coded added, removed, and modified lines

Load sample JSON instantly to test the tool without pasting your own data

Copy input or output to clipboard with a single button click

All parsing done client-side — your JSON never leaves the browser

Frequently asked questions

Does the formatter send my JSON to a server?

No. All parsing and formatting is performed by JavaScript running locally in your browser tab. Nothing is transmitted to any server.

What indentation styles are supported?

You can choose 2-space, 4-space, or tab indentation from the Indent selector before clicking Format.

What does the diff mode compare exactly?

It performs a deep key-by-key comparison of two JSON objects and reports added keys (green), removed keys (red), and modified values (yellow) in a Git-style output.

Does it handle nested objects and arrays?

Yes. The formatter and validator handle arbitrarily nested objects, arrays, strings, numbers, booleans, and null values. The diff mode recursively compares nested objects and shows the path to each difference.

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Full Guide Available

JSON Formatter Complete Guide

Learn formatting, validation, minification, and JSON diff comparison with practical examples.

What's inside

Format & validate JSON

Minify & compare JSON diffs

Common questions answered

Read Full Guide

JSON Formatter

Input JSON

Output

JSON Formatter, Validator & Diff Tool

How to use it

Key features

Frequently asked questions

JSON Formatter Complete Guide

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