JSON Formatter & Validator

Paste JSON to format, validate, and minify. Syntax highlighted output with error detection.

Input

All processing happens entirely in your browser. No data is sent to any server.

What the JSON formatter does

Paste raw or minified JSON and this tool pretty-prints it with consistent indentation and syntax highlighting, validates it against the JSON spec, and can minify it back to a single line. When the JSON is invalid, it points to where the parser failed so you can fix it fast. Everything runs in your browser — nothing you paste is uploaded.

How to format and validate JSON

  1. Paste your JSON into the input.
  2. Format to pretty-print it, or minify to strip whitespace for transport.
  3. If it's invalid, read the error and jump to the offending character.

Why JSON is easy to break

JSON is stricter than it looks. The most common causes of "invalid JSON" are a trailing comma after the last item, single quotes instead of double quotes, unquoted keys, and comments — none of which strict JSON allows. A validator catches these instantly instead of leaving you to hunt through a wall of text.

Debugging an API token? A JWT payload is JSON too — decode it to read the claims. For raw encoded strings, reach for the Base64 encoder / decoder.

Frequently asked questions

What makes JSON invalid?

Trailing commas, single quotes, unquoted object keys, comments, and unescaped control characters. Keys and string values must use double quotes.

Format vs minify — which do I want?

Format (pretty-print) for reading and debugging; minify to shrink payload size before sending over the wire.

Is my data sent anywhere?

No — formatting and validation run entirely in your browser.

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