JSON Formatter
Paste JSON, get it prettified. Free, no signup, runs in your browser.
How It Works
Paste any JSON string — minified, messy, or single-line — into the input field and click Format. The output shows clean, indented JSON with 2-space indentation. If the JSON is invalid, you will see a specific error message pointing to what went wrong.
Everything runs in your browser. No server receives your data — formatting is done using JavaScript on your device.
What Is JSON?
JSON (JavaScript Object Notation) is a lightweight data-interchange format used by virtually every web API. It is easy for humans to read when formatted properly, but APIs and logs often return it as a single minified line.
A JSON formatter takes that compact output and adds line breaks and indentation, making it easy to read, debug, and understand the structure of the data.
Common JSON Mistakes
If you see an Invalid JSON message, one of these is usually the cause:
| Mistake | Fix |
|---|---|
| Trailing comma after the last item | Remove the extra comma |
| Single quotes around strings or keys | Use double quotes |
| Unquoted object keys | Wrap every key in double quotes |
| Comments (// or /* */) | JSON does not allow comments; remove them |
| Missing closing bracket or brace | Balance every [ ] and { } |
Frequently Asked Questions
How do I format or prettify JSON?
Paste your JSON into the input box and click Format. The tool parses it and prints clean, indented output with line breaks. Use Copy result to copy the formatted JSON to your clipboard.
What indentation does it use?
The formatted output uses two-space indentation, the most common style for readable JSON. Nested objects and arrays are laid out on their own lines so the structure is easy to scan.
Does it validate the JSON?
Yes. If the input is not valid JSON, the tool shows an Invalid JSON message with the specific parser error, which helps you pinpoint issues like a trailing comma, a missing bracket, or an unquoted key.
Is my data uploaded to a server?
No. Parsing and formatting run entirely in your browser using JavaScript, so the JSON you paste never leaves your device. It also works offline once the page has loaded, which is useful for sensitive data.
Can it also minify JSON or repair broken JSON?
This tool prettifies and validates JSON but does not repair invalid input. To collapse JSON back into a single compact line, use the JSON Minifier; for a strict validity check, use the JSON Validator.