Free Online Formatter:

Re-indent and normalize JSON6 with a choice of spaces or tabs and sorted or original key order.

TL;DR: Paste JSON6, choose an indent and key order, and copy the clean result. The formatter parses with json-6 and re-emits with JSON6.stringify, so output is canonical JSON6: unquoted simple keys, double-quoted strings, decimal numbers. Comments are not kept. Everything runs locally.

Format JSON6 Online

The sample is squashed onto a few lines on purpose. Change the options to see the layout change.

Indent

Key order

JSON6 input

Formatted output

Private by design: everything runs locally in your browser using the reference json-6 parser. Your text is never uploaded, logged or sent to any server, and it is gone when you close the tab.

How the Formatter Works

The formatter is a round trip: JSON6.parse turns the text into a value, then JSON6.stringify(value, null, space, { sortKeys }) writes it back. space is a number of spaces (2 or 4), a tab character, or 0 for a single line, exactly like JSON.stringify.

Because formatting goes through a value, anything that is only syntax disappears: comments, quote choices, number radix, underscore separators and trailing commas. A hand-written 0b1010 comes back as 10. That is the right behavior for normalizing data, and the wrong one for hand-maintained files where the author's spelling matters; keep those out of an automated formatter.

What the Output Looks Like

Keys: written bare when they are plain identifiers, quoted when they contain spaces, dashes, brackets or quote characters. By default they are sorted; choose "Keep original order" to preserve them.
Strings: always double-quoted. A line break inside a string stays a raw line break, which JSON6 allows. An apostrophe inside a string is written as \', which is valid JSON6 but not valid JSON.
Arrays: holes are preserved ([1,,3]) and undefined elements are written as the keyword.
Objects: a member whose value is undefined is dropped.
No trailing commas and no comments are emitted.

There is no quote-style option. That is a JSON5 stringify feature; the json-6 serializer does not offer it, so this page does not pretend otherwise.

Before and After

Input:

{zeta:1,alpha:{b:`x`,a:0b11},list:[1,,3]}

Output with 2-space indent and sorted keys:

{ alpha: { a: 3, b: "x" }, list: [ 1, , 3 ], zeta: 1 }

Note that the hole in the array is written on its own line as an empty member. Use the one-line indent setting for the compact [1,,3] form.

FAQ

Is my data sent to a server?

No. Everything happens in your browser.

Why were my comments removed?

Comments are not part of the parsed value, and the serializer can only write values. Keep a commented source file and format a copy.

Why is there a backslash before an apostrophe?

json-6 escapes single quotes inside double-quoted strings. It is valid JSON6; for strict JSON use the converter.

Can I get single-quoted strings?

Not from this tool. json-6 1.1.7 always emits double-quoted strings and has no quote option.

Keep Going

Validate your text, minify it, or read how JSON6 strings and numbers are written.

Online Minifier Syntax Guide