JSON Formatter & Validator - Free Online JSON Tool

How to format JSON

Paste, format, copy. Takes about five seconds.

01
Paste your JSON
Paste raw JSON into the left panel. Minified, broken, or already formatted — it doesn't matter. The tool figures it out.
02
Format or minify
Format adds 2-space indentation and syntax highlighting so you can actually read it. Minify strips all whitespace — useful before embedding JSON in code or sending it over the wire.
03
Read the error if something's wrong
If the JSON is invalid, the error message shows the exact line and character. Usually it's a missing comma, a trailing comma, or a single-quoted string.
04
Copy
One click copies the output. Paste it into your code, PR comment, or wherever you need it.

When you'd reach for this

Reading API responses

Paste a minified API response and instantly see the structure. Nested objects that were one long line become readable in a second.

Debugging config files

JSON config files fail silently when there's a syntax error. Paste it here and the validator tells you exactly where the problem is.

Minifying before deployment

Strip whitespace from JSON before embedding it in a script tag or sending it as a request payload. Saves a few KB and looks cleaner.

Pasting into PR comments

Formatted JSON in a code block is much easier for reviewers to read than a wall of minified text.

Frequently asked questions

Free, no account, no limits.

No. Everything runs in your browser. Your JSON never leaves your device.

Missing commas, extra commas, trailing commas, unquoted keys, single-quoted strings, and mismatched brackets or braces. It won't catch logical errors — only syntax.

Yes, up to your browser's memory limit. Files up to a few MB work fine. Very large files (50 MB+) may be slow.

Standard JSON doesn't allow comments. If you're working with JSONC (JSON with Comments), strip the comments first. Most editors have a command for this.

Yes, though editing large JSON on a phone screen is painful. Works fine for quick checks.

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How to format JSON

Paste, format, copy. Takes about five seconds.

Paste your JSON

Paste raw JSON into the left panel. Minified, broken, or already formatted — it doesn't matter. The tool figures it out.

Format or minify

Format adds 2-space indentation and syntax highlighting so you can actually read it. Minify strips all whitespace — useful before embedding JSON in code or sending it over the wire.

Read the error if something's wrong

If the JSON is invalid, the error message shows the exact line and character. Usually it's a missing comma, a trailing comma, or a single-quoted string.

Copy

One click copies the output. Paste it into your code, PR comment, or wherever you need it.