JSON Formatter & Validator

Format or minify JSON

1. Paste JSON or import one UTF-8 text file. The input limit is 1 MiB and the maximum container nesting depth is 64.
2. Choose two or four spaces and select Format, or select Minify to remove whitespace outside strings. Invalid input produces an error rather than a repaired document.
3. Review the output, then copy it or download a JSON file. Editing the input or changing indentation clears the previous result until you process it again.

What changes and what stays the same

Formatting changes only whitespace outside strings. The formatter uses line feeds, indents nonempty objects and arrays, and puts one space after each object colon. Minifying removes the four whitespace characters allowed by JSON outside strings.

Numbers remain exactly as written. A large integer such as 9007199254740993 is not rounded, and forms such as 1e400, -0 and 1.2300 retain their original spelling. Receiving software may still impose its own numeric limits.

Object members stay in their original order. Repeated names also stay present: syntax validation does not mean that duplicate names are portable or desirable. Different applications can interpret repeated names differently.

Quoted strings and escape sequences remain unchanged. The tool does not sort keys, normalize Unicode, repair syntax, validate a schema or check whether an API will accept your data.

Formatting examples

The input {"ok":true,"items":[1,2]} can be expanded into indented lines without changing any keys, values or array positions. Empty objects and arrays remain compact.

Minifying { "note": "keep two spaces" } produces {"note":"keep two spaces"}. Spaces inside the string are part of its value and stay intact.

The input {"id":9007199254740993,"id":2} keeps both id members and the large integer exactly as written. The valid-syntax label does not certify that duplicate keys are safe for the receiving application.

Syntax validation has limits

Use strict JSON: double-quoted strings, no comments, no trailing commas and no NaN or Infinity literals. Any single top-level JSON value is allowed, including a string, number, boolean or null. JSON5 and multiple JSON Lines records are outside this tool.

Files must be UTF-8 without a byte-order mark. Input is limited to 1 MiB, nesting to 64 containers and output to 8 MiB. Escaped unpaired Unicode surrogates can pass JSON syntax while remaining problematic for other applications. Validation does not establish schema correctness, security or interoperability.

Local processing and sensitive content

The tool processes text locally without tool-added uploads, history or input-bearing links. Copy and download happen only on request. Normal site services remain separate; avoid pasting secrets into a page unless you trust the surrounding environment.