JSON Formatter

Format and validate JSON online — free and private

JSON is everywhere — API responses, config files, log lines — and it's easy to read when it's laid out nicely and painful when it arrives as one giant unbroken line. This tool takes messy or minified JSON, checks that it's valid, and pretty-prints it with clean indentation so you can actually read it. If something's wrong, it tells you what and where. Everything runs in your browser — the data you paste never leaves your device.

That privacy matters more than people realise. Developers routinely paste API payloads into online formatters, and those payloads can contain tokens, personal data, or internal details. Here nothing is uploaded, so you can format a real response without sending it to someone's server.

Beautify vs minify

Formatting (or "beautifying") adds line breaks and indentation so the structure is obvious at a glance — nested objects and arrays line up, and you can follow the hierarchy. You choose the indent that matches your project: two spaces, four spaces, or tabs.

Minifying does the opposite: it strips every bit of optional whitespace to produce the shortest valid string. That's what you want when size matters — sending JSON over the network, storing it, or pasting it into a single-line config value. Both directions describe the exact same data; only the spacing changes.

Validation and common errors

The most useful part of a JSON tool is often the error message. As you type, the status line tells you whether the JSON is valid, and if it isn't, it points to the line and position of the problem so you can jump straight there instead of hunting.

A few mistakes come up again and again:

• Trailing commas — a comma after the last item in an object or array. Valid in JavaScript, not in JSON.
• Single quotes — JSON requires double quotes around both keys and string values.
• Unquoted keys — every key must be a quoted string.
• Missing or extra brackets/braces — an unclosed { or [, or one too many.

When you'll reach for it

You paste an API response to read it. You clean up a config file before committing it. You check whether a webhook payload is well-formed. You minify a chunk of JSON to drop into an environment variable. You're debugging and just need to see the shape of the data. All of these are a few seconds of work once the JSON is formatted and validated.

Works on your phone

The formatter runs in your phone's browser with nothing to install. Paste JSON from an email, a chat, or a docs app, format it, and copy the result back out. Since everything happens locally, it works the same whether you're online or not once the page has loaded.

Privacy: your data never leaves your device

Parsing, formatting, minifying, and validation all happen in your browser using its built-in JSON engine. Nothing is uploaded, nothing is stored, and there's no account. Close the tab and the data is gone, because it was never sent anywhere. That makes it safe to work with real payloads that might contain sensitive values.

Frequently asked questions

How do I format JSON?

Paste your JSON and tap Format. It's parsed and re-printed with clean indentation — 2 spaces, 4 spaces, or tabs — and you can copy the result.

What's the difference between format and minify?

Format adds indentation so JSON is easy to read; minify strips all whitespace to make the smallest possible string. Same data, different spacing.

Why is my JSON invalid?

Usually a trailing comma, single quotes instead of double quotes, an unquoted key, or a missing bracket. The tool shows what went wrong and the line and position.

Is my JSON uploaded to a server?

No. Everything happens in your browser — your data never leaves your device, and nothing is stored or sent anywhere.