Paste minified or messy JSON to instantly beautify, validate, and syntax-highlight it — all in your browser, nothing sent to a server.
JSON (JavaScript Object Notation) is a lightweight text format used to exchange data between applications and APIs. Minified JSON strips all whitespace to reduce file size, but this makes it nearly impossible to read. Formatting (or beautifying) adds proper indentation and line breaks so you can quickly understand the structure, spot problems, and debug issues.
No. All formatting and validation happens entirely in your browser using JavaScript. Your JSON never leaves your device, so you can safely paste sensitive configuration files, API responses, or private data.
Minifying JSON removes all unnecessary whitespace (spaces, tabs, newlines) to produce the smallest possible string. This is useful when sending JSON over a network or storing it in a database where size matters — a minified JSON file can be 20–40% smaller than its formatted version.
The most frequent JSON errors are: trailing commas after the last item in an array or object (not allowed in JSON, unlike JavaScript); single quotes instead of double quotes for strings or keys; unquoted keys; using undefined, NaN, or Infinity (not valid JSON values); and forgetting to escape special characters like backslashes or newlines inside strings.
JSON is a strict text format derived from JavaScript object syntax, but with key differences: all keys must be double-quoted strings, trailing commas are not allowed, and special values like undefined, NaN, Infinity, and functions are not permitted. A JavaScript object literal is more flexible and is native code, while JSON is always a string that must be parsed.