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JSON Formatter
Format, beautify, minify and validate JSON without uploading it. Paste JSON or load a file, get a precise error for invalid syntax, then copy or download — nothing is sent to a server.
All files are processed only in your browser and are never uploaded to any server.
Quick answer
Format, beautify, minify and validate JSON free in your browser, with nothing sent to a server: paste JSON or load a .json file, get a precise error message when the syntax is invalid, then copy the result or download it as a .json file. A private JSON formatter for API payloads and config files that may contain tokens or personal data.
- Input
- Paste JSON, or load a .json / .txt file
- Output
- Copy to clipboard, or download as .json
- Validation
- Yes · invalid JSON reports the parse error
- Formatting
- Beautify with 2, 4 or 8 spaces · or minify
- Views
- Edit with line numbers, Tree, and Text
- Data sent to a server
- None · everything runs locally
- Price
- Free · no registration
- Works on
- Any modern browser · Windows, macOS, Linux, iOS, Android
How to use this JSON Formatter
- Paste or type your JSON into the editor, or load a .json file.
- Click Format to beautify it, or Minify to compress it.
- Copy the result, or click Download to save it as a .json file.
Why is my JSON invalid? The usual suspects
JSON looks simple but its rules are strict, so a single character can break a payload. The errors people hit most often are a trailing comma before a closing brace or bracket, keys or strings wrapped in single quotes instead of double quotes, unquoted keys, and comments — none of which standard JSON allows.
Paste the document here and the validator returns a precise parse error at the offending position instead of a generic failure. Because everything runs in your browser, this is safe for API responses, tokens and internal config that you would rather not send to a third-party server.
- Trailing commas: the last item in an object or array must not be followed by a comma.
- Single quotes: strings and keys must use double quotes.
- Comments: standard JSON does not allow // or /* */ comments.
- Unquoted keys: { key: 1 } is invalid; it must be { "key": 1 }.
Frequently Asked Questions
Is my JSON data private?
Yes. Formatting happens entirely in your browser; no data is transmitted or stored on any server.
Does it validate JSON?
Yes. Invalid JSON will produce a clear error message instead of a result.
Can I download the formatted JSON?
Yes. Click Download to save the formatted result as a .json file, or use Copy to paste it anywhere.
What does “Unexpected token” in JSON mean?
It means the parser hit a character it did not expect at that position. The usual causes are a trailing comma, single quotes instead of double quotes, an unquoted key, or a stray comment. The error here points to the location so you can fix it.