JSON Formatter — Beautify, Minify, Validate

What it is

A JSON formatter turns one long line of JSON into readable, indented text, or strips all optional whitespace to make it smaller. Use it to inspect an API response, tidy a config file, or find the spot where the syntax broke. The result updates as you type, so there is no button to press.

How to use

1. Paste your JSON into the input box.
2. Choose 2 spaces, 4 spaces or tab indentation, or pick Minify.
3. Turn on Sort keys if you want the keys ordered by character code. It reaches objects nested inside objects and inside arrays.
4. Copy the result. If there is an error, the line and column are shown, so start fixing there.

How it works

• The grammar is JSON as in RFC 8259 (ECMA-404): double-quoted keys and strings only, no comments, no trailing commas.
• Error positions are 1-based lines and columns. \n, \r\n and a lone \r each count as one line break. Columns count characters (code points), so an emoji takes one column, and the caret under the error line mirrors tabs. Numbers that overflow to Infinity (such as 1e999) become null with a warning, and nesting deeper than 512 levels is rejected with an explicit message.
• Key sorting works at every level in code-unit order (uppercase before lowercase) and leaves array order alone. A key that appears twice in one object ({"a":1,"a":2}) keeps only its last value under the JSON rules, so the result is still produced but a warning names the key and the line and column where it repeats. Because of how JavaScript objects work, integer-like keys such as "1" and "2" always come first in numeric order, whatever the option says.
• Output keeps Korean, Chinese and emoji characters as they are and escapes only what JSON requires, such as \n and \". A Unicode escape such as "\u0041" is written out as "A".
• Numbers are read as JavaScript Numbers. Integers beyond 2^53 are not preserved exactly, and a warning tells you so.

Examples

Input	Option	Result
{"b":1,"a":{"d":2,"c":3}}	Minify + sort keys	{"a":{"c":3,"d":2},"b":1}
{"name":"홍길동"}	2 spaces	multi-line, "name": "홍길동"
{"a": 1,}	—	line 1, column 9: unexpected character }
{"id": 12345678901234567890}	Minify	{"id":12345678901234567000} (warning shown)