Reading API responses
Turn a single long line from an API or log into readable, indented JSON in one click.
JSON Formatter Online — Free JSON Beautifier & Validator
Paste messy JSON below and get clean, indented output in one click. This free JSON formatter online also validates your data, points to the exact line and column of any error, minifies for production and shows a collapsible tree you can browse.
Format JSON
Runs locally in your browser
No API key
Free, no sign-up required
JSON input
Paste or type JSON to format it. Everything stays in your browser.
Output
Indent
Numbers and text are kept exactly as typed. Strict JSON only: no comments, trailing commas or single quotes.
Result
—Status
0 BOutput size
0Lines
0Keys
0Nesting depth
0Values
Tree view
Valid JSON appears here as a tree you can open and close.
The guide
JSON Formatter Online: Beautify, Validate, Pretty Print and Minify JSON
Turn messy or minified JSON into readable, properly indented data, check syntax errors, and compact it again when you need a smaller payload.
What Is a JSON Formatter?
A JSON formatter turns compact or messy JSON into clean, readable text with consistent indentation. A JSON beautifier or pretty printer does the same basic job, while a validator checks whether the JSON syntax is valid.
Use Beautify or pretty print when you are reading an API response, configuration file or log. Use Minify when you want a compact payload. If the JSON is invalid, this tool points you to the problem by line and column.
Popular Uses
Debugging and validation
Find missing commas, extra brackets and bad quotes by line and column before they break your app.
Shipping smaller files
Minify config and payloads to remove extra bytes, or sort keys to make files easy to compare.
Common JSON Errors and Fixes
| Example | Problem | Fix |
|---|---|---|
| {"a":1,} | Trailing comma | Delete the comma after the last item. |
| {'a':1} | Single quotes | Use double quotes around keys and text. |
| {a:1} | Unquoted key | Write the key as "a". |
| {"a":1 "b":2} | Missing comma | Add a comma between the two items. |
| {"n":007} | Leading zero | Write 7, or "007" as text. |
| {"a":1} // note | Comment | JSON has no comments, so remove them. |
How to Format JSON Online for Free
- Paste your JSON into the input box, or use Upload to open a .json file.
- Choose Beautify or Minify, then pick 2 spaces, 4 spaces or a tab. Turn on Sort keys if you want them in alphabetical order.
- If the message shows an error, use Go to error to jump to the exact spot and fix it.
- Copy the result or download it as a .json file. Open the tree view to browse the data and copy the path to any value.
Tips & Best Practices
- Keep quotes in the right place: JSON keys and text always use double quotes, never single quotes.
- Use Sort keys before comparing two JSON files, so the same data always appears in the same order.
- Minify before sending JSON over the network, and beautify when you need to read or review it.
- Click a row in the tree view and use Copy path to get the address of a value, such as $.users[0].name.
Limitations & Privacy
Privacy
Formatting happens locally in your browser. The JSON you paste or upload is not sent to a server or saved.
Limitations
The formatter accepts up to 5 million characters and 400 levels of nesting. It checks strict JSON, so comments and trailing commas are reported as errors. The tree view shows the first 500 items of a long list.
From people using this tool
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