Is my JSON data sent to a server?

No. All formatting, validation, and minification happens in your browser using JavaScript's built-in JSON parser. Nothing is transmitted over the network.

What is the maximum JSON size this tool can handle?

The tool processes JSON up to the memory limit of your browser tab, typically several hundred megabytes. For extremely large files, consider using a local command-line tool like jq.

Does the formatter change my data?

No. Formatting only adds or removes whitespace. The actual key-value pairs, arrays, and nested structures remain identical.

JSON Formatter & Validator

Format, beautify, minify, and validate JSON data online. Instant error detection with line numbers.

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Input

Output

How to Format JSON Online

Paste raw JSON into the input field and click Format. The tool parses your data with the browser's native JSON engine and prints it with consistent indentation. No data leaves your browser — every operation runs locally in JavaScript. Working with JSON Web Tokens? Use the JWT Decoder to inspect token payloads, which are Base64-encoded JSON.

Common JSON Errors and How to Fix Them

Most JSON parsing failures come from a few recurring mistakes: trailing commas after the last property in an object or array, single quotes instead of double quotes around keys and string values, and unescaped special characters inside strings. The validator pinpoints the exact position of the first syntax error so you can jump straight to the problem.

Trailing Commas

The JSON specification does not allow a comma after the final element. While JavaScript tolerates trailing commas in object literals, JSON.parse() rejects them. Remove the comma before the closing brace or bracket.

Single Quotes

JSON requires double quotes around all keys and string values. If your data comes from a Python repr() or a logging library that uses single quotes, replace them with double quotes before parsing.

JSON Minification

Minifying strips all whitespace from JSON without changing the data. This reduces payload size for API responses and configuration files. Click Minify to collapse the entire structure onto a single line. If your JSON is embedded in a URL, run it through the URL Encoder / Decoder to handle percent-encoding.

Keyboard Shortcuts

Press Ctrl+Enter (or Cmd+Enter on Mac) while focused in the input area to format instantly.

Frequently Asked Questions

Is my JSON data sent to a server?: No. All formatting, validation, and minification happens in your browser using JavaScript's built-in JSON parser. Nothing is transmitted over the network.
What is the maximum JSON size this tool can handle?: The tool processes JSON up to the memory limit of your browser tab, typically several hundred megabytes. For extremely large files, consider using a local command-line tool like jq.
Does the formatter change my data?: No. Formatting only adds or removes whitespace. The actual key-value pairs, arrays, and nested structures remain identical.