JSON Formatter and Validator
Formats and validates raw JSON, pretty printing it with proper indentation and highlighting syntax errors with a line reference.
How to Use This Tool
- 1 Paste unformatted, minified, or API response JSON into the text editor.
- 2 Click "Format JSON" to auto-indent with standard 2-space indentation.
- 3 Check the automated syntax inspector: invalid syntax pinpoints the exact line and column character.
- 4 Use "Minify" to strip whitespace for API payloads or click "Copy to Clipboard".
Debugging API Payloads Privately in the Browser
Minified JSON, the kind returned by most APIs, is unreadable as a single unbroken line, which makes debugging painful without a formatter. A formatter does two things at once: it reindents the structure so nesting is visually clear, and it validates the syntax, catching problems like a trailing comma, a missing quote, or a mismatched bracket, all of which are common typing mistakes that produce cryptic error messages further down a script.
Because this tool runs entirely in the browser using JavaScript native JSON parser, nothing is sent to a server, which matters if the JSON contains anything sensitive like API responses with account data.
The minify option does the reverse operation, useful when preparing a JSON payload for production where whitespace just adds unnecessary size.