JSON Formatter
Validate and format JSON with readable indentation.
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Maximum input: 5 MB. Files are processed locally; large outputs are available as downloads with a shortened preview.
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How to use JSON Formatter
- Add your JSON data. Paste text or select a file from your device.
- Choose your options. Review the settings and select Convert.
- Save your result. Preview, copy, or download the output.
Know your output.
JSON integers outside the safe JavaScript range are rejected to avoid silent rounding. Quote large IDs before converting. YAML aliases and custom tags are not supported.
Conversion happens locally. Refreshing or closing this tab clears the workspace; downloaded files remain on your device.
JSON Formatter: conversion behavior
Validate JSON syntax and display parsed data with two- or four-space indentation. Processing stays in your browser.
Use it to inspect a compact API response and identify syntax errors before another conversion.
- JSON requires quoted property names and does not accept comments or trailing commas.
- This is a syntax check, not JSON Schema or business-rule validation.
- Parsing and reserialization can change duplicate keys, numeric spellings and key order. Keep originals when exact bytes matter.
- Unsafe large integers are rejected; decimal numbers use JavaScript numeric precision.
Questions about JSON Formatter
Does it automatically fix invalid JSON?
No. It reports an error so you can correct the source without an automatic guess changing its meaning.
Can it validate my JSON Schema?
Not in this version. Syntax validity does not prove that required fields and values satisfy a schema.
Content reviewed · Conversion behavior & testing