JSON Formatter

What is a JSON formatter?

JSON (JavaScript Object Notation) is a lightweight data format that is easy for machines to parse and generate. People, however, struggle with JSON that has been minified into a single long line or pasted with inconsistent spacing. A JSON formatter re-indents the text so objects, arrays and values line up visually, making it quick to understand the shape of the data and spot mistakes.

A good formatter does more than add spaces. It also checks the syntax and tells you exactly where a problem is, which is why this tool combines formatting with validation, beautifying and minifying in one place.

How to format JSON

1. Paste your JSON into the input box above, or open a .json file.
2. Choose an indentation style (2 spaces, 4 spaces or tabs).
3. Press Format (or Ctrl/⌘ + Enter).
4. Copy the result or download it as a file.

JSON formatting example

Compact input:

{"name":"John","age":30,"active":true}

Formatted output (2 spaces):

{
  "name": "John",
  "age": 30,
  "active": true
}

JSON formatter features

• Format / pretty-print — turn minified JSON into readable, indented text.
• Validate — detect syntax errors with a clear line and column message.
• Beautify — choose 2 spaces, 4 spaces or tabs for clean structure.
• Minify — remove whitespace to shrink payloads for APIs and storage.
• Tree view — inspect large structures as a collapsible, searchable tree.
• File support — paste, type, drag-and-drop or open a file.
• Private — everything runs locally in your browser.

Common JSON errors

• Missing comma — forgot to separate two values in an array or object.
• Trailing comma — a comma after the last element is not valid JSON.
• Missing quote — object keys must be wrapped in double quotes.
• Unmatched braces or brackets — every { needs a } and every [ needs a ].
• Invalid value — only strings, numbers, booleans, null, objects and arrays are allowed (no undefined or functions).
• Malformed string — unescaped control characters or quotes break strings.

JSON vs JSON5

Standard JSON is strict: keys must be double-quoted, no comments, no trailing commas, and no unquoted values. JSON5 is a superset that relaxes these rules (allowing comments, unquoted keys, trailing commas and more) for configuration files. This tool follows the standard JSON specification, so JSON5 will be reported as invalid — convert it to strict JSON first if you need to format it here.

Frequently asked questions