JSON Formatter

Beautify or minify JSON with live error checking.

A JSON formatter is a tool that takes messy or minified JSON and re-indents it into clean, readable, properly nested text. This one formats or minifies JSON online with 2-space, 4-space or tab indentation, optional alphabetical key sorting, and instant syntax checking that points to the exact line and column of any error. Runs fully in your browser — nothing is uploaded.

How to use JSON Formatter

  1. Paste or upload your JSON

    Drop your JSON into the input pane, upload a .json file, or hit “Sample” to try it instantly — no sign-up required.

  2. Pick your indentation

    Choose 2 spaces, 4 spaces or tabs so the output matches your project’s style and stays easy to read and diff.

  3. Beautify or minify

    Leave it off for clean, readable JSON, or flip “Minify” to compress everything onto one compact, ship-ready line.

  4. Sort keys (optional)

    Turn on “Sort object keys (A → Z)” for stable, review-friendly diffs when you compare two files.

  5. Watch the live check

    Invalid JSON is caught as you type — the banner pinpoints the exact line and column so you can fix it fast.

  6. Copy or download

    Grab the formatted result with one click, or download it as a .json file. Everything stays 100% in your browser.

Frequently asked questions

Is my JSON sent to a server?

Never. Parsing and formatting both run locally in your browser using JavaScript's built-in JSON engine — nothing is uploaded, logged or stored, so it's safe to paste sensitive or internal payloads.

What's the difference between Beautify and Minify?

Beautify adds the line breaks and indentation that make JSON easy for people to read; Minify strips all of that whitespace so the file is as small as possible to send over the wire. Flip the “Minify” toggle to switch between the two.

Will formatting change my data?

Almost never — the spacing is all that changes for normal data, and array order is always kept. A few technical edge cases do get re-written when the JSON is re-serialised: very large integers (beyond 2^53) can lose precision, number formats are normalised (1e3 becomes 1000, 1.0 becomes 1), and if a key appears twice only the last value is kept. The optional “Sort object keys” also reorders keys alphabetically (array order stays untouched).

Why is my JSON marked invalid?

Strict JSON doesn't allow trailing commas, single quotes, unquoted keys or comments, so any of those will trip it up. The banner points to the exact line and column where parsing broke, so you can jump straight to the fix.

How do I format and beautify JSON online for free?

Paste your JSON or upload a .json file and this free online JSON formatter instantly beautifies it with clean 2-space, 4-space or tab indentation — no sign-up and no upload. Use the “Minify” toggle to compress it back to one line whenever you need the smallest payload.

Can it handle large files?

Yes. Because everything happens on your own device, you can format multi-megabyte files with no upload — speed depends on your browser and machine rather than any server-side size limit.

Can I sort JSON keys alphabetically with this formatter?

Yes. Turn on “Sort object keys (A → Z)” and the JSON formatter reorders every object's keys alphabetically while leaving array order untouched — ideal for producing stable, review-friendly diffs and comparing two JSON files.

Can I view and read messy JSON from an API?

Yes — that's one of the most common uses. Paste a raw, single-line API response and the formatter indents it into a clean, readable tree so you can scan the structure, spot the field you need and copy the tidy version.

Does the JSON formatter work offline?

Once the page has loaded, yes — all formatting, minifying and validation run locally in your browser with no further network calls, so it keeps working even if you go offline and your data never leaves your device.

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