JSON Formatter & Validator
Beautify messy JSON, minify it, or validate it — with the exact line and column of any error.
JSON Formatter & Validator
🔒 Nothing you enter is sent anywhere or stored. All processing happens in your browser.
Features
Format, minify and validate
Pretty-print messy JSON with clean indentation, minify it to one compact line, or check whether it's valid.
Pinpoints errors
Invalid JSON is reported with the exact line and column so you can fix it fast.
Private by design
Parsing runs in your browser, so API responses and config files with secrets never leave your device.
One-click copy
Copy the formatted or minified result straight to your clipboard.
How it works — in four simple steps
No signup, nothing to install — it all runs in your browser.
Paste your JSON
Drop in the JSON you want to tidy, shrink or check.
Choose an action
Format to pretty-print, Minify to compact it, or Validate to check it's well-formed.
Fix any errors
If it's invalid, jump to the reported line and column and correct the problem.
Copy the result
Copy the clean output into your code, request body or config file.
How it works
JSON (JavaScript Object Notation) is the most common format for exchanging structured data between programs. It's readable in principle, but real-world JSON often arrives minified onto one line or with inconsistent spacing. This tool cleans it up and checks it for errors.
Format parses your JSON and re-prints it with consistent indentation (2 spaces, 4 spaces, or tabs) so nested objects and arrays become easy to scan. Minify does the opposite, stripping all unnecessary whitespace to produce the smallest valid string for transmission or storage. Validate simply confirms whether the input is well-formed JSON.
When JSON is invalid, the tool reports the browser's parse error and calculates the line and column where parsing failed, so you can jump straight to the missing comma, unquoted key, or stray bracket. Because parsing uses the browser's native JSON engine and runs entirely on your device, you can safely paste API responses or config files containing sensitive values.
Examples
Opening and creating JSON files
A .json file is just structured plain text, so you don't need special software to work with it:
To open one: drag its contents into the box above (or open it in any text editor) and press Format to pretty-print and validate it — far easier to read than raw, single-line JSON.
To create one: type your data as key/value pairs inside curly braces, use square brackets for lists, wrap keys and text values in double quotes, and separate items with commas. Format it here to confirm it's valid, then save it with a .json extension in any editor.
Common gotchas the validator catches: trailing commas, single quotes instead of double, missing commas between items, and unclosed brackets — it reports the exact line and column so you can fix them fast.