Developer

JSON Formatter
& Validator

Paste any JSON — messy, minified, or broken — and instantly beautify, validate, or minify it. Syntax errors are pinpointed with line and column numbers.

Input JSON
Output
Waiting for input…

What is JSON?

JSON (JavaScript Object Notation) is a lightweight text format for storing and transporting data. It's human-readable and language-independent, making it the universal language of APIs, config files, and databases.

Common JSON errors this tool catches

Trailing commas after the last item in an array or object, missing quotes around keys, single quotes instead of double quotes, unescaped special characters in strings, mismatched brackets, and duplicate keys.

Minify vs Beautify

Beautifying adds indentation and line breaks making JSON easy to read. Minifying strips all whitespace to reduce file size — useful before sending JSON over a network or storing in a database.

Why does my JSON show an error at line 1?

Line 1 errors usually mean the root value is invalid — for example, pasting a Python dictionary with single quotes or trailing commas. Make sure keys are double-quoted strings and there are no commas after the last item.

Does this tool send my data anywhere?

No. All processing happens locally in your browser. Your JSON never leaves your device.

What's the maximum JSON size I can paste?

There's no hard limit imposed by the tool. Large files (several MB) may be slow depending on your browser's JavaScript engine.