JSON Formatter & Validator

Format, validate, and beautify JSON with syntax highlighting

JSON (JavaScript Object Notation) is a lightweight data-interchange format. It is easy for humans to read and write and easy for machines to parse and generate. The JSON Formatter helps format, validate, minify, and clean JSON payloads.

How to use JSON Formatter & Validator

  1. Paste or Upload JSON. Paste your raw JSON text into the input panel or click Upload to select a local file.
  2. Select Formatting Depth. Choose your preferred indentation spacing (e.g. 2 spaces, 4 spaces, or Tab).
  3. Format or Minify. Click Format to beautify the code with syntax highlighting, or click Minify to compact it.
  4. Copy or Download Output. Use the Copy Button to save the result to your clipboard or download it as a .json file.

Features

  • Interactive Code Highlights: Colored syntax representation for object keys, arrays, numbers, and strings.
  • One-Click Minifier: Compacts JSON strings into a single line.
  • Auto-Repair: Corrects missing quotes, trailing commas, and unquoted keys automatically.
  • JSON Key Sorting: Sorts properties alphabetically for easier differential comparison.

Why use this tool

  • Zero Server Transmission: Rest assured that your JSON data stays completely local to your browser, protecting API keys and client data.
  • Error Debugging: Identifies the exact line number and missing character when JSON validation fails.
  • Optimized Loading: Minifies payloads to save bandwidth and improve API response times.

Frequently asked questions

How do I format and validate JSON online?

Paste your JSON into the input box and the tool parses it immediately. Valid JSON is shown as a collapsible tree and as formatted text, while invalid JSON shows an error so you can find the problem. You can pick a 2 or 4 space indent and copy or download the result.

How do I minify JSON?

Switch to the Minified tab, or use the minify action, to remove all spaces and line breaks from valid JSON. The data itself is unchanged, only the whitespace is removed, which makes the text smaller for APIs, config files or URLs.

Why does my JSON say invalid or unexpected token?

The most common causes are a trailing comma after the last item, single quotes instead of double quotes, unquoted keys, comments, and curly smart quotes pasted from a document. JSON requires double quotes for every key and string. The repair button fixes smart quotes and trailing commas for you.

Can I sort JSON keys alphabetically?

Yes. Turn on the sort keys option and object keys are ordered alphabetically at every level of nesting in the formatted and minified output. Arrays keep their original order. This is handy for comparing two JSON documents or producing stable diffs.

What is the difference between JSON and a JavaScript object?

JSON is a strict text format, while a JavaScript object literal is code. JSON needs double-quoted keys and strings and does not allow comments, trailing commas, undefined, functions or single quotes. Text that works in JavaScript source often fails JSON validation for these reasons.

Can I open a JSON file instead of pasting it?

Yes. Use the upload button to load a .json file from your device into the editor, then format, search the tree or minify it. The file is read by your browser and is not sent to a server. Very large files can be slow to render as a tree because every node is drawn.

Is my JSON data sent to any server?

No. All validation and formatting happen locally in your browser using pure client-side JavaScript. No data is transmitted externally.

Why does my JSON parsing fail?

Common mistakes include trailing commas, single quotes instead of double quotes, or missing quotes around property keys. The validator highlights these errors with line numbers.

What is the difference between Formatted and Minified JSON?

Formatted JSON includes spacing, line breaks, and indentation for human readability. Minified JSON strips out all whitespace and newlines to create the smallest possible file size for server transmission.

Does this formatter upload my JSON data?

Never. Your data is formatted entirely inside your browser tab using client-side JavaScript.

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