Will it accept JSON5 or JSONC (with comments)?

Yes — toggle "Lenient mode" to allow comments, trailing commas and single-quoted strings. The output is always strict, RFC 8259 JSON.

How big a payload can it handle?

Tested up to 50 MB. Larger files may slow your browser; for huge logs, split them first.

Is my JSON sent to your server?

No. Parsing, formatting and validation all happen locally in your browser — your data never leaves the page.

Does it sort keys alphabetically?

Yes — toggle "Sort keys" before formatting. Useful for diffing two JSON files that differ only in key order.

JSON Formatter — Free Online Tool

What is the JSON Formatter?

The JSON Formatter is a free online json tools from Markvibe. Beautify and indent JSON instantly. It runs entirely in your browser — your data never gets uploaded — and works on desktop, tablet and mobile with no sign-up.

Reviewed by The Markvibe Team · Last updated 2026-06-28

Example

A worked example so you know exactly what to expect.

Input

{"name":"Markvibe","tools":500,"free":true}

Output

{
  "name": "Markvibe",
  "tools": 500,
  "free": true
}

How to use JSON Formatter

1Paste your JSON — minified, single-line or broken — into the editor.
2Pick an indent (2 spaces, 4 spaces, or tab) and click Format.
3Invalid JSON is highlighted with the exact line, column and error message (trailing comma, unquoted key, unterminated string).
4Use the tree view to fold/unfold objects and arrays; click a key to copy its dotted path (data.users[0].email).
5Copy the formatted JSON or download it as a .json file.