JSON Formatter

How the JSON Formatter works

The formatter reads your input with a strict JSON parser that follows the JSON standard (RFC 8259). It checks every character as it goes, so the first syntax error is reported with its exact line and column instead of a vague "unexpected token" message.

Once the input is known to be valid, the formatter writes it back out with one value per line and the indentation you chose. It works on the original text of each value rather than converting it to JavaScript numbers and back, so large integers such as database IDs keep all their digits, and strings keep their original escape sequences. Only the whitespace between values changes.

How to use the JSON Formatter

1. Paste your JSON into the input box, open a .json file, or select Load example.
2. Choose the indentation you want: 2 spaces, 4 spaces or tabs. Tick Sort keys to order object properties alphabetically.
3. Select Format JSON, or press Ctrl + Enter (Cmd + Enter on a Mac).
4. Copy the formatted result or download it as a .json file. If there is an error, the message shows the line and column and the cursor jumps to it.

Example

This minified input:

{"id":1042,"name":"Wireless Keyboard","tags":["electronics","accessories"],"price":49.99,"inStock":true}

is formatted with 2-space indentation as:

{
  "id": 1042,
  "name": "Wireless Keyboard",
  "tags": [
    "electronics",
    "accessories"
  ],
  "price": 49.99,
  "inStock": true
}

If a comma were missing after 1042, the tool would report Invalid JSON at line 1, column 11: Expected ',' or '}' after property value but found '"'.

Common use cases

• Reading a minified API response copied from browser developer tools or a log file.
• Tidying configuration files such as appsettings.json, package.json or tsconfig.json before committing them.
• Producing consistently indented JSON so code reviews show real changes instead of whitespace noise.
• Finding the exact position of a syntax error, such as a missing comma, in a large payload.
• Sorting keys so two JSON documents can be compared side by side more easily.

Common errors and how to fix them

The error says: Expected ',' or '}' after property value

A value is not followed by a comma or a closing brace. The usual cause is a missing comma between two properties, or a stray double quote that ended a string early. The cursor jumps to the reported column, so check the characters immediately before it.

The error mentions comments, single quotes or trailing commas

The input is relaxed or JavaScript-style JSON rather than standard JSON, and this formatter is strict on purpose. Run it through the JSON Beautifier first, which repairs comments, single quotes and trailing commas, then format the repaired output here.

Unterminated string: a line break is not allowed inside a string

A string was opened but a real newline appeared before its closing quote. Replace the line break with the escape sequence \n, or look for a missing closing double quote earlier on the same line.

The output looks identical to the input

The JSON was already indented exactly the way you asked for. Change the indentation setting, or tick Sort keys, to confirm the tool ran.

Frequently asked questions