JSON Formatter

The JSON Formatter beautifies, validates, and minifies JSON. Paste your data to pretty-print it with your choice of indentation, catch syntax errors with a clear message, or minify it for production — all processed locally in your browser. It's built for everyday developer tasks like untangling a deeply nested API response or double-checking that hand-written JSON is syntactically valid before pasting it into a request body. Because it relies on the browser's strict, standards-compliant JSON.parse, it won't accept looser dialects like JSON5 or JSONC — comments and trailing commas are flagged as errors rather than silently stripped.

Beginner⏱ 30 secondsUpdated 2026-07-08

Paste your JSON

Style

Valid JSON

{
  "name": "EveryFix",
  "tools": 86,
  "free": true,
  "tags": [
    "fast",
    "private"
  ]
}

Formats, minifies, and validates JSON instantly in your browser — your data is never uploaded. Choose an indent style, or Minify to strip whitespace for production.

How This Tool Works

Paste JSON into the box and it is formatted and validated as you type. Pick 2 spaces, 4 spaces, tabs, or Minify, and copy the result. Invalid JSON shows a clear error so you can fix it.

Formula & Method

The tool parses your input with the browser’s native JSON engine. If it is valid, it re-serializes it with your chosen indentation (or with no whitespace to minify); if it is invalid, it reports the exact syntax error.

Example Calculation

Paste a compact API response, choose 2-space indentation, and it expands into clean, readable JSON — or switch to Minify to collapse it back to a single line for production. Paste {"user":{"id":42,"name":"Alex","roles":["admin","editor"]}} with a trailing comma after "editor"] left in by mistake, and the tool immediately flags the syntax error instead of silently formatting broken JSON.

Please note: This calculator provides estimates for general informational purposes only. Results may not be accurate for every situation — use your judgment and consult a relevant professional when it matters.

Frequently Asked Questions

Is my JSON data private?+

Yes. Everything is parsed and formatted in your own browser — your JSON is never uploaded to or stored on any server.

Why does it say my JSON is invalid?+

The tool uses a strict JSON parser, so common issues like trailing commas, single quotes, or unquoted keys will flag an error. The message points to where the problem is.

Can it minify JSON too?+

Yes — choose “Minify” to strip all whitespace and produce the smallest valid JSON, which is handy for production or APIs.

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

No — the formatter validates against strict JSON (RFC 8259), so comments, trailing commas, and unquoted keys will all trigger an error rather than being silently accepted. Strip those out first if your file relies on those looser features.

Is there a size limit on how much JSON I can paste?+

There's no hard-coded limit, and since parsing runs locally with your browser's native JSON engine, it can typically handle files well into the multi-megabyte range without issue.

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