What is JSON formatting?

JSON formatting (also called pretty-printing or beautifying) adds consistent indentation and line breaks to raw or minified JSON, making it human-readable. A formatter parses the JSON and re-serializes it with whitespace according to your chosen indent size.

Is my JSON data safe to paste here?

Yes. This JSON formatter runs entirely in your browser using JavaScript. No data is sent to any server. Your JSON never leaves your device, making it safe to use with sensitive or private data.

What is the difference between JSON formatting and JSON validation?

JSON validation checks whether your JSON string follows the JSON specification (RFC 8259) — correct syntax, properly quoted keys, no trailing commas, etc. JSON formatting takes valid JSON and rearranges whitespace for readability. This tool does both: it validates first, then formats if the JSON is valid.

What are common JSON syntax errors?

Common JSON errors include: trailing commas after the last element, single quotes instead of double quotes around keys or strings, unquoted keys, undefined or NaN values (not valid JSON), missing commas between elements, and mismatched brackets or braces.

What does minify JSON mean?

Minifying JSON removes all unnecessary whitespace (spaces, tabs, newlines) to produce the smallest possible valid JSON string. This reduces file size and is useful for API responses or storing JSON in databases where space matters.

Can I sort JSON keys alphabetically?

Yes. This tool includes a "Sort keys" option that rearranges all object keys in alphabetical order before formatting. This is useful for comparing two JSON objects or producing consistent, reproducible output.

Free · Browser-only · No sign-up

JSON Formatter & Validator

Paste raw or minified JSON to instantly format, validate, and pretty-print it. Highlights syntax errors with precise line and column numbers. Runs entirely in your browser — no data is ever uploaded.

Format / Pretty-printValidate syntaxMinifySort keys100% offline

indent

sort keys

input

output

About this tool

This JSON formatter runs entirely in your browser — no data is sent to any server. It validates JSON syntax, formats with configurable indentation, and optionally sorts keys alphabetically. Useful when working with API responses.

Features

Format

Pretty-print with 2-space, 4-space, or tab indentation

Validate

Exact error messages with line and column numbers

Minify

Strip whitespace to produce the smallest valid JSON

Sort keys

Alphabetically sort all object keys for consistency

Browser-only

No data sent to any server — works completely offline

Copy

One-click copy of formatted output to clipboard

How to use

1
Paste JSON
Copy any raw, minified, or malformed JSON into the input field.
2
Set options
Choose indent size (2 spaces, 4 spaces, or tab). Optionally enable Sort keys or Minify.
3
Format
Click Format or press the keyboard shortcut. Errors are shown with line numbers.
4
Copy
Click Copy to copy the result to your clipboard.

Frequently asked questions

What causes a JSON parse error?

The most common causes are trailing commas, single-quoted strings (JSON requires double quotes), unquoted keys, comments in the JSON (not supported), and invalid escape sequences in strings.

What is the difference between JSON and JavaScript object literals?

JSON is a strict data interchange format. Unlike JavaScript objects, JSON requires all keys to be double-quoted strings, does not support functions or undefined values, and does not allow comments or trailing commas.

Can I format very large JSON files?

Yes. Since processing happens in your browser, performance depends on your device. JSON files up to several megabytes format instantly. Very large files (50 MB+) may cause the browser tab to slow down.

What is JSON Schema?

JSON Schema is a vocabulary that allows you to define the structure, types, and constraints for JSON documents. This tool validates JSON syntax, not JSON Schema compliance.

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