What does 'validate' actually check?

The tool runs your input through a strict JSON parser. If it isn't valid JSON — a stray comma, an unquoted key, a missing bracket — you get an error message with the exact line and column so you can jump straight to the problem.

What's the difference between pretty-print and minify?

Pretty-print adds indentation and line breaks so the JSON is readable. Minify strips every non-essential character, which is what you want when embedding JSON in an API request, config value, or URL.

Does 'sort keys' change the meaning of my JSON?

No. JSON objects are unordered by spec, so sorting keys alphabetically produces a semantically identical document. It's useful for diffing two JSON files or for deterministic snapshots.

Can it handle huge JSON files?

Free users can load files up to 10 MB. Pro users are only limited by browser memory — multi-megabyte API responses and log dumps format fine.

Does it support JSONC or JSON5 (comments, trailing commas)?

Not yet — the parser follows the strict JSON spec. Comments and trailing commas will show up as validation errors. A JSON5 mode is on the roadmap.

Will it preserve number precision?

It uses JavaScript's native number type, so integers up to 2^53 are exact. For very large IDs (like Twitter snowflake IDs), keep them as strings in your source to avoid precision loss.

Format and validate JSON

Format, validate, minify, and sort JSON with clear error messages pointing to the exact line and column — free, private, and 100% in your browser.

JSON input

Free tier: up to 10.00 MB per file. Pro removes the cap.

Mode

Indent

KeysSort alphabetically

Output

Output will appear here.

What people use it for

Debug an API response by pasting it in and getting readable, indented JSON.
Validate a config file before shipping and see the exact line of a syntax error.
Minify JSON before embedding it in a URL, header, or environment variable.
Sort keys alphabetically to get a clean diff between two JSON files.
Clean up JSON copied from browser DevTools, curl output, or a webhook log.
Format package.json, tsconfig.json, or eslint.config.json to a consistent style.

Our free JSON formatter lets you format, validate, and minify JSON online without uploading a single byte. Paste any JSON — an API response, a config file, a webhook payload — and get instantly readable, indented output, or a minified single-line version ready to drop into a URL, header, or environment variable.

It doubles as a JSON validator: invalid input gets a clear error message pointing to the exact line and column of the problem, so you can find a missing comma or unclosed bracket in seconds. Toggle alphabetical key sorting for deterministic diffs, switch between 2-space, 4-space, and tab indentation, and download the result as a .json file.

Because everything runs locally, it is a safe way to pretty-print JSON containing API keys, customer data, internal configs, or anything else you would rather not paste into a random online JSON viewer. It is the fastest way to beautify JSON, minify JSON, or check whether a file is valid JSON without opening an editor or writing a script.

How it works

1
Paste or drop your JSON
Paste directly into the box, or drop a .json file. It stays on your device.
2
Pick pretty or minified
Choose indent size, sort keys alphabetically, or switch to minified single-line output.
3
Copy or download
Grab the formatted JSON via clipboard or download it as a .json file. Invalid input gets a line-and-column error.

Frequently asked questions

No. Parsing, formatting, and validation all happen in your browser with the native JSON engine — nothing leaves your device.

Want this converter on your website?

Pro members can embed any Minitooler converter on their own site — styled to match, with no branding beyond a small credit link. One iframe, unlimited use, still 100% in the browser.

Unlock embeds — $5/mo

Accent color

Theme

Background

Text color

Width

Height

Embeds are a Pro feature

Upgrade to unlock a customizable iframe snippet you can paste into any website — colors, theme, and size all tuned to match your brand.

Go Pro — $5/mo