Format and beautify JSON into readable, indented text -- keeps big numbers, key order and duplicate keys exactly as typed. Fast, free, and built for simple browser-based workflows.
Formatting happens entirely in this browser tab. The JSON you paste, drop or open here — an API response, a config file, an export with customer data — is never sent anywhere.
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JSON Formatter is a free online tool that turns messy or minified JSON into clean, indented text you can actually read. Paste JSON, an API response, or open a .json file, and it lays out every object and array with consistent spacing -- without changing a single number, key, or character.
It earns its keep whenever raw JSON lands somewhere unreadable: a single-line API response dumped into a log, a config file someone minified, or a webhook payload you need to inspect before writing code against it. Turning that into properly indented text makes nested objects and arrays easy to scan by eye, and turning on Sort Keys A-Z makes it simple to compare two versions of the same structure side by side.
Formatting happens entirely in this browser tab -- the JSON never leaves your device or touches this site's servers. That matters when the payload includes real user data, internal API keys, or anything else from production you would rather not paste into a site you don't control. Big numbers, duplicate keys, and unusual characters are preserved exactly, because a formatter that silently changes your data isn't trustworthy.
Paste JSON into the box, click Open file to choose a .json file, or drag one onto the box. Click "Try an example" to see a sample with a large id.
Pick 2 spaces, 4 spaces or Tab under Indent, tick Sort keys A-Z to order object keys alphabetically, or tick the JSONC option to allow comments and trailing commas.
Press Format JSON, or Ctrl+Enter from anywhere on the page. Valid JSON appears indented in the result box; invalid JSON shows the exact line, column and a Go to error link.
Use Copy for the clipboard or Download to save it as formatted.json. Clear resets the input, output and any error state.
Yes! All our tools are 100% free to use with no hidden costs, no registration required, and no credit card needed.
Absolutely. All tools run entirely in your browser (client-side). Your data never leaves your device and is not sent to our servers.
Yes, once the page is loaded, the tool will continue to work even if you lose internet connection since it runs in your browser.
There is no strict character limit, but very large amounts of text (100,000+ characters) may slow down your browser.
Yes! All our tools are free for both personal and commercial use.
It scans your JSON for syntax errors as part of formatting, so a broken file will not slip through -- but a full pass/fail verdict, warnings about risky-but-valid JSON, and document statistics are JSON Validator's job, not this page's. Use this tool when you want readable output; use JSON Validator when you specifically need a pass/fail check with warnings and stats.
No. It never guesses what you meant or rewrites your data -- if your JSON has a syntax error, it shows you exactly where and why, with the line, column and a short snippet, so you can fix the actual mistake yourself. A tool that silently repairs invalid data can hide real bugs in whatever produced it.
No. Numbers are copied exactly as typed, including very large integers, trailing zeros like 1.0, and scientific notation like 1e400. Most tools parse JSON into JavaScript numbers first, which silently rounds any integer above about 9 quadrillion -- this one never does that.
Both are kept, in the order they appeared. JSON technically allows duplicate keys even though most parsers only keep the last one; this tool never silently drops data, and the result message tells you how many duplicates it found.
Only if you turn on the JSONC option. Standard JSON does not allow // or /* */ comments or trailing commas, so by default they are treated as errors. Turning on JSONC accepts both, which is useful for files like tsconfig.json or VS Code settings that use that relaxed syntax.
No -- things like single-quoted strings or an unquoted key are valid JavaScript but not valid JSON, and this tool points out exactly where the mismatch is rather than silently accepting them. Switching to double-quoted keys and strings throughout turns it into valid JSON.
Not as a single input -- this tool expects one JSON document, so pasting several values back to back produces an error that names NDJSON as the likely cause. Format each line of an NDJSON file separately instead.
Most files up to a few megabytes format instantly. Above about 10MB you will see a brief "this may take a few seconds" notice before it runs, and pathologically deep nesting that would produce an enormous amount of output is refused with a message instead of freezing the tab.
No -- sorting only reorders the keys inside objects, alphabetically and recursively at every level, including objects nested inside arrays. The order of items within an array is never touched, since that order is often meaningful, like a list of steps.
It does not -- any character you typed, including emoji, accented letters, or a Unicode escape sequence, is preserved exactly as written. A literal character stays literal, and an escape sequence stays an escape sequence; formatting only changes whitespace, never the content of a string.
Not on this page: it produces indented text you can copy or download. To explore JSON as a tree you can open, close and search, and to copy the exact path to any value, use JSON Viewer.