JSON is the language the modern web speaks — APIs, config files, data exports and app storage all use it — but raw JSON is usually written for machines, not people: one endless line, or a tangle of inconsistent spacing. This free JSON formatter fixes that in one click. Paste any JSON, choose a 2-space, 4-space or tab indent, and read it as a clean, structured document. It also minifies (for when size matters), validates (for when you only need a yes or no), and when the JSON is broken it shows the browser’s exact parse error so you can find the fault fast. Everything runs locally in your browser — your data is never uploaded, which makes the tool safe for production payloads, tokens and private exports alike.
How to use this JSON formatter
Paste your JSON into the top box and press Format JSON. The result appears in the lower box, ready to copy. Minify does the opposite: it strips every unnecessary space and line break to produce the smallest valid JSON, which is what you want before embedding data in a request or a file where bytes count. Validate checks the input without changing anything and simply tells you whether it parses. If it does not, the error message from the parser appears under the buttons — modern browsers report the position of the problem, which is usually a missing comma, an unquoted key, a trailing comma or single quotes where JSON demands double quotes.
Why formatting matters more than it looks
Formatted JSON is not about beauty; it is about finding things. In a minified payload, one wrong value hides in a wall of characters. Formatted, the structure is visible at a glance: nesting depth shows you which object owns which key, arrays line up so a missing element stands out, and diffs between two versions become readable line by line. That is why developers format JSON before reviewing API responses, debugging webhooks, writing config files and checking database exports — and why so many “the API is broken” mysteries end the moment someone formats the response and actually sees it.
Common JSON errors and how to fix them
Trailing commas — the last item in an object or array cannot be followed by a comma in strict JSON, even though JavaScript allows it. Single quotes — keys and strings must use double quotes. Unquoted keys — every key needs quotes, unlike a JavaScript object literal. Comments — JSON has none; remove any // or /* */ notes from config files saved as .json. Special values — NaN, Infinity and undefined are not valid JSON; use null instead. The validator above will stop at the first of these it meets: fix that spot, validate again, and repeat until it passes — in practice it rarely takes more than two or three rounds.
Private by design
Because the formatting happens with JavaScript on your own device, nothing you paste is sent to a server, logged or stored. That matters more for JSON than for most data: payloads routinely contain email addresses, access tokens, order details and internal IDs. A formatter that uploads your data to “the cloud” is asking you to trust it with all of that for a job your browser can do alone. This one never sees your data at all — close the tab and it is gone.
Frequently asked questions
Is this JSON formatter free and unlimited?
Yes. No sign-up, no file-size limit in practice (very large pastes depend only on your device’s memory), and no watermark or premium tier.
What is the difference between formatting and validating?
Validating only answers “is this valid JSON?” Formatting rewrites valid JSON with consistent indentation so humans can read it. Minifying rewrites it with no wasted characters so machines can store or send it cheaply.
Can I format JSON with comments or trailing commas?
No — and neither can any strict JSON tool, because those features belong to JSON5 and JavaScript, not JSON. Remove comments and trailing commas and the same text will format cleanly; the error message will point at the first offending spot.
Does the tool keep or send my JSON anywhere?
No. All parsing happens in your browser tab. You can verify it by loading the page and disconnecting from the internet — the tool keeps working.
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