JSON Formatter and Validator
Processed locally in your browser. Your input is not uploaded or saved by this tool.
Text output preserves number spelling and duplicate keys. The tree uses JavaScript values: large numbers can round and duplicate keys show only the last value.
Paste JSON, then choose Format, Minify or Validate.
How it works
Format adds whitespace with 2- or 4-space indentation. Minify removes whitespace outside strings. Both preserve original strings, number spelling and key order. Validation uses the browser’s strict JSON parser: comments, trailing commas and single-quoted strings are not JSON. Error line and column are shown when the browser supplies a position.
Example
Formatting {"count":2,"items":[true,null]} places properties and array values on separate indented lines. Minifying it removes only unnecessary whitespace, not spaces inside string values.
Frequently asked questions
Can I format JSON containing large integers?
Yes. Formatted text and downloads retain numeric tokens such as 9007199254740993 without rounding. The optional tree view uses native JavaScript numbers and may show rounded values.
Can I paste confidential JSON?
This tool processes JSON locally without uploading or saving it. Still, avoid working with secrets on a shared device and do not share clipboard contents with untrusted applications.