JSON Formatter & Validator

Paste JSON directly, upload a .json file, or drag one onto the input panel. Works with any valid structure: objects, arrays, nested data, or a single value.

A trailing comma, single quotes instead of double, an unquoted key, a stray NaN or Infinity, even a hidden BOM character at the start of a file: each gets its own specific explanation, with the exact line and column, instead of a generic parser error. Valid JSON with a duplicate key gets flagged too, since the last value silently overwrites earlier ones.

Valid JSON is instantly indented and color coded by type: keys, strings, numbers, and booleans all shown differently, so nested structure is easy to scan.

Copy the formatted JSON to your clipboard, or save it as a .json file by clicking the download button. Minify first if you want the compact version instead.