Is my JSON data uploaded anywhere?

No. This formatter runs entirely in your browser using JavaScript's built-in JSON parser — your data is never sent to a server, so it's safe to paste production payloads, tokens and customer records.

Do I have to click a button to format?

No. Formatting happens the moment you paste or type, and re-runs whenever you change the indentation, sorting or minify setting. The Format and Minify buttons are there to switch which output you want, not to trigger the work.

Can it fix invalid JSON?

Usually, yes. If the strict parser rejects your input, a repair pass handles the common causes — trailing or duplicated commas, missing commas, single or curly quotes, unquoted keys, // and /* */ comments, unterminated strings, unclosed brackets, hex and BigInt numbers, and Python or JavaScript literals like True, None, NaN and undefined. Several JSON objects pasted back to back (NDJSON) are wrapped into an array. Every repair is listed so you can see what changed, and if the repair can't produce valid JSON the original error is reported instead — your data is never silently altered.

Does this tool validate JSON as well as format it?

Yes. Formatting requires parsing first, so any syntax error is caught and reported with its line, column and a caret under the exact character. Clicking the reported location moves your cursor there so you can fix it immediately.

What does Tree view show that the text view doesn't?

Tree view lets you collapse and expand individual objects and arrays, search every key and value at once, and copy the JSONPath of any node — for example $.items[0].sku — which is far faster than scrolling a large API response looking for one field.

What is "Sort keys" for?

It orders every object's keys alphabetically, recursively. Two responses that list the same fields in a different order then produce identical files, which makes diffing configs and API payloads in Git much easier to read.

Is there a size limit?

There's no artificial limit — very large files are only bounded by your browser's own memory. Syntax highlighting and the line-number gutter switch off automatically on huge documents so the page stays responsive.

JSON Formatter & Validator

Auto-formats the moment you paste, repairs broken JSON, and shows every error's exact line and column.

Indent

INPUTLn 1, Col 1

Formatted JSON appears here…

Nothing to check yet — paste or drop some JSON above.

Processed 100% in your browser — nothing you enter here is ever uploaded.

Common use cases

Debugging an API response

Paste a minified response straight from your network tab to see nested fields clearly instead of scanning one long line.

Reviewing a config file before committing

Catch a stray comma or missing bracket in a package.json or tsconfig.json before it breaks someone else's build.

Fixing JSON mangled by copy-paste

Text copied from a chat app, log file, PDF or email loses quotes and gains stray commas — the repair pass puts it back together instead of just reporting an error.

Finding one field in a huge payload

Search every key and value in tree view, then copy the JSONPath of the node you found and paste it straight into your code.

How to use the JSON Formatter

Paste or drop your JSON into the left panel — it formats itself as soon as it lands, with no button to press. Nothing you enter leaves your browser.

Broken JSON still gets formatted: trailing commas, single quotes, unquoted keys, comments, NaN and Python-style True/None are repaired automatically, and the status bar lists exactly what was changed.

If it can't be repaired, the error is reported with its line and column and a caret under the offending character — click the location to jump the cursor straight there.

Switch between "Format" and "Minify", pick 2-space, 4-space or tab indentation, and turn on "Sort keys" to order every object alphabetically for clean diffs.

Use "Tree" view to search keys and values across the whole document, collapse branches you don't care about, and copy the JSONPath of any node with one click.

Copy the result, or download it as a .json file — formatted or minified, whichever mode you're in.