JSON Formatter & Validator | DevNexus

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How It Works

Paste Your JSON

Paste raw, minified, or partially-formatted JSON into the left input panel.

Click Format

Hit the Format button (or press F) to instantly pretty-print your JSON with 2 or 4 space indent.

Review Errors

If your JSON has syntax errors, the status bar shows the exact line and column number of the issue.

Copy or Download

Copy the formatted output to clipboard, or download it as a .json file with one click.

Format, Validate, and Minify JSON in Your Browser

JSON is the backbone of modern APIs and config files. Our Free JSON Formatter & Validator runs entirely in your browser: paste minified or messy JSON, format it with one click, and get instant validation and error locations. No data is sent to any server—ideal for sensitive payloads and offline use.

How the formatter works

The tool uses the native JSON.parse() and JSON.stringify() APIs, so it conforms to ECMA-404 and RFC 8259. Format expands your JSON with consistent indentation; Minify strips whitespace for the smallest output. Sort Keys reorders object keys alphabetically at every level, which helps with diffs and normalizing configs.

Common use cases

Pretty-printing API responses for debugging
Validating webhook payloads or config files before deployment
Minifying JSON for storage or transmission
Sorting keys for consistent version control diffs

Frequently Asked Questions

What is a JSON Formatter?

A JSON Formatter takes raw or minified JSON text and re-formats it with consistent indentation and line breaks, making it easier to read and debug. Our tool also validates the JSON structure and highlights syntax errors.

Is my JSON data safe?

Completely. All formatting and validation happens 100% in your browser using JavaScript. Your JSON is never sent to any server. You can even use this tool while offline.

What's the difference between Format and Minify?

Formatting (pretty-printing) expands JSON with indentation and newlines for human readability. Minifying removes all unnecessary whitespace to produce the smallest possible JSON string — ideal for API responses and storage.

What does Sort Keys do?

Sort Keys alphabetically reorders all object keys at every level of nesting. This is useful for diffing JSON objects, normalizing configuration files, or making keys easier to scan.

What JSON formatting standards are supported?

Our tool uses the native JSON.parse() and JSON.stringify() APIs, which conform to the ECMA-404 and RFC 8259 JSON standards. It supports all JSON data types: objects, arrays, strings, numbers, booleans, and null.

Can I format very large JSON files?

Yes. Since the tool runs client-side, the limit is your browser's available memory. For most modern browsers on a typical workstation, files up to 10–50 MB format in under a second.

How It Works

Paste Your JSON

Paste raw, minified, or partially-formatted JSON into the left input panel.

Click Format

Hit the Format button (or press F) to instantly pretty-print your JSON with 2 or 4 space indent.

Review Errors

If your JSON has syntax errors, the status bar shows the exact line and column number of the issue.

Copy or Download

Copy the formatted output to clipboard, or download it as a .json file with one click.

Format, Validate, and Minify JSON in Your Browser

How the formatter works

Common use cases

Pretty-printing API responses for debugging

Validating webhook payloads or config files before deployment

Minifying JSON for storage or transmission

Sorting keys for consistent version control diffs

Frequently Asked Questions

What is a JSON Formatter?

Is my JSON data safe?

Completely. All formatting and validation happens 100% in your browser using JavaScript. Your JSON is never sent to any server. You can even use this tool while offline.

What's the difference between Format and Minify?

What does Sort Keys do?

Sort Keys alphabetically reorders all object keys at every level of nesting. This is useful for diffing JSON objects, normalizing configuration files, or making keys easier to scan.

What JSON formatting standards are supported?

Can I format very large JSON files?

Yes. Since the tool runs client-side, the limit is your browser's available memory. For most modern browsers on a typical workstation, files up to 10–50 MB format in under a second.