JSON Formatter and Validator – Beautify, Minify and Check JSON

How to use the JSON formatter

1. Paste your JSON into the JSON box, or press Try an example.
2. Choose the indent: 2 spaces, 4 spaces, tabs, or Minify for a single line.
3. Tick Sort keys A–Z if you want object keys in alphabetical order.
4. Copy the result, download it as a file, or press Use as input to keep editing.

The status line confirms the JSON is valid and shows how its size changed.

What makes JSON valid

JSON (JavaScript Object Notation) has a small, strict set of rules:

• Objects use curly braces, with keys in double quotes: {"name": "Ada"}.
• Arrays use square brackets: [1, 2, 3].
• Values can be strings, numbers, true, false, null, objects or arrays.
• Strings must use double quotes, and special characters such as new lines must be escaped (\n).
• Items are separated by commas, with no trailing comma after the last one.
• No comments are allowed.

Example

This is invalid because of the single quotes and the trailing comma:

{'name': 'Ada', 'born': 1815,}

The valid version is:

{"name": "Ada", "born": 1815}

Pretty-print or minify?

Pretty-printed JSON is easier to read, review and debug, so use it in configuration files, documentation and when inspecting API responses. Minified JSON is smaller and faster to send, so it is usually what servers and browsers exchange. Many projects store pretty JSON in source control and let the build minify it.

Common uses

• Debugging APIs: make a long response readable.
• Editing configuration: package.json, tsconfig.json, app settings.
• Checking data before importing it into a database or spreadsheet.
• Comparing documents: format and sort both, then compare them.
• Learning: see the structure of nested objects clearly.

Large files

The formatter handles files of several megabytes comfortably on most devices. For very large files, minified output is quicker to produce than pretty output because there is less text to display.

JSON vs JavaScript objects

JSON looks like JavaScript, but it is a stricter data format. JavaScript allows single quotes, unquoted keys, trailing commas, comments and values such as undefined or functions; JSON allows none of these. If you copy an object from JavaScript code into a JSON file, run it through the formatter first — it will point to the exact character that needs fixing. Some tools accept relaxed formats such as JSON5 or JSONC (JSON with comments), used in editor settings files, but standard JSON parsers will reject them.

Numbers deserve a note too: JSON has no special values for infinity or “not a number”, and very large integers can lose precision in JavaScript. If you work with IDs longer than about 15 digits, keep them as strings.

Related tools

Convert between formats with CSV to JSON and YAML to JSON. Inspect tokens with the JWT decoder, and decode encoded data with the Base64 decoder.