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JSON Formatter & Validator

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Precise Mapping.
Instant Processing.
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Last reviewed:

Free online JSON formatter and validator

Paste JSON to format, validate, minify or sort it instantly. Invalid JSON is flagged with the parser message and the line and column of the error. Choose 2 spaces, 4 spaces or tabs, or minify to a single line.

Everything runs in your browser. Your data is never uploaded or stored.

How to format JSON

Paste your JSON into the input box.
Pick the output style: 2 spaces, 4 spaces, tab, or minify.
Optionally sort keys A to Z, applied to every nested object.
Copy the result with one click. Errors show the line and column to fix.
Real-World Example

Calculation In Practice

When to use a JSON formatter

1
Reading API responses: Turn a minified payload into something you can scan.
2
Debugging config files: Find the missing comma or quote with the line and column.
3
Shrinking payloads: Minify JSON before embedding it in code or a request.
4
Diff-friendly output: Sort keys so two JSON files compare cleanly.

Frequently Asked Questions

Is my JSON uploaded anywhere?

No. Parsing and formatting happen entirely in your browser.

What counts as valid JSON?

Strict JSON: double-quoted keys and strings, no trailing commas, no comments.

Does sorting keys change the data?

No. It only reorders object keys alphabetically. Array order is preserved.

Why does the error show a line and column?

The browser JSON parser reports the character position of the first error. We convert it to a line and column to help you find it.

Author Spotlight

The ToolsACE Team - ToolsACE.io Team

The ToolsACE Team

Last reviewed October 2026

Our developer tools team builds in-browser formatters that parse your data locally, so nothing you paste is ever uploaded.

JSON ParsingClient-Side ProcessingSoftware Engineering Team