Data
JSON Formatter & Beautifier
Paste any JSON value and get a clean, two-space indented copy you can paste anywhere.
Written by Jay Sudha · Published · Last updated
Press ⌘ Enter to run
4 lines · 124 chars
Ready; press Run or ⌘ Enter
How this tool handles files
- Processing
- In your browser, on-device
- Storage
- Nothing stored
- Output
- A file you download
- Your responsibility
- Review before official use
- Runs in your browser. Your file is processed on your own device and, on this site, is not uploaded to our servers.
- Nothing is stored. Your file and its output are gone the moment you close or reload the page.
- Review sensitive files (bank, ID, medical) and check the output before sharing it.
Every tool on FormatOS runs in your browser. Read our Privacy Policy and File Handling Policy.
Common uses
- Make minified JSON readable
- Format API responses for debugging
Limitations
- Input must be valid JSON
Turning minified JSON back into something readable
This tool takes a single JSON value and re-prints it with consistent two-space indentation. Paste a minified API response, a config blob copied from a log line, or a one-line export, press Run (or Ctrl/Cmd+Enter), and the output pane shows the same data laid out across nested lines you can actually scan. Internally it parses your text and re-serializes it, so the result is a clean, canonical copy rather than a guess at where line breaks should go.
A common workflow is debugging: copy a compact response from your browser's network tab, drop it in, and read the indented version to find the field you need. Copy puts the result on your clipboard and Download saves it as a .json file, and both panes show live line and character counts.
Fixed two-space indentation and what re-serializing changes
The indentation here is fixed at two spaces; there is no width slider, tab option, or sort-keys toggle. If you need the opposite direction, the companion JSON minifier strips all whitespace for compact storage or transport, and the JSON validator checks parseability without reformatting. Picking the right one of the three avoids surprises.
Because the tool parses and rebuilds your JSON, the output is normalized rather than a literal reflow of your text. Insignificant whitespace and your original line breaks are discarded and replaced with the standard layout. If a key appears twice in the same object, JSON parsing keeps only the last value, so duplicates silently collapse. Comments and trailing commas are not valid JSON and will be rejected outright rather than stripped, so this is not a tool for cleaning up JSON5 or commented config.
Local processing and handling invalid input
Everything runs in your browser; on this site, the text you paste is not uploaded, which matters for responses containing tokens or internal IDs. Closing the tab clears it, and Reset sample restores the built-in example.
The one hard requirement is that your input must be valid JSON. If it is not, you will see the parser's own error message instead of formatted output, often pointing near the offending character. The usual culprits are trailing commas after the last element, single quotes instead of double quotes, unquoted keys, or a stray closing brace. Fix the flagged spot and run again. For pinning down a syntax problem before formatting, the JSON validator surfaces the same first parser message on its own.
Frequently asked questions
Normally no: it re-indents the parsed JSON, so keys, values and structure stay the same. Because the JSON is parsed and written back, a few edge cases change: integers beyond 9007199254740991 lose precision, 1.50 is written as 1.5, a repeated key keeps only its last value, and keys that are whole numbers move to the front of their object.
Two-space indentation, the common default for readable JSON. The result is ready to paste into code, a config file, or documentation.
It must be valid JSON to format. If it can't be parsed, you'll see an error so you can fix the syntax: use the JSON Validator to locate the exact problem.
No. The conversion runs in your browser; your text or file is processed on your own device and, on this site, is not uploaded to a server, and we do not intentionally store it.
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Tool last reviewed: September 27, 2026 · Report a problem