Paste JSON to instantly format, validate, or minify it. Live validation with friendly error messages.
This free JSON formatter, validator, and beautifier turns raw or minified JSON into clean, readable output — and tells you instantly when something is wrong. Paste your data, and it pretty-prints, validates, or compresses it in a single click.
JSON is everywhere: API responses, configuration files, log entries, database exports, and browser localStorage all rely on it. But it is also unforgiving — one stray comma or a single quote where a double quote belongs, and the whole document fails to parse. The validator here checks your input as you type and pinpoints exactly where it breaks, with the line and position of the error called out so you can fix it fast instead of squinting at a wall of text. When the JSON is valid, the beautifier re-indents it with your chosen spacing (two spaces, four spaces, or tabs), nests objects and arrays cleanly, and shows a running count of characters and keys. People use it to:
Everything runs locally in your browser. Your JSON is never uploaded, logged, or sent to any server, so it is safe to paste API credentials, user records, or proprietary business data. Once the page has loaded it keeps working with no internet connection, and you can copy the result or download it straight to a .json file.
.json file.Paste your JSON in and the validator will pinpoint the exact line and position of the error. Common causes: trailing commas (valid in JS but not JSON), single quotes instead of double quotes, unescaped special characters in strings, missing commas, or mismatched brackets.
Minify strips all whitespace and line breaks. For a typical 100KB formatted JSON, minification reduces it to ~60–70KB — ideal for API responses, localStorage, and config files where size matters.
Yes — all formatting and validation runs in your browser. Your JSON is never transmitted to any server, logged, or stored. Safe for API credentials, user data, and proprietary business data.
The most common culprits are trailing commas after the last item in an object or array, single quotes instead of the double quotes JSON requires, unquoted keys, comments (not allowed in standard JSON), and unescaped characters inside strings. Numbers with leading zeros and missing commas between values also fail. Paste your text and the validator names the exact problem and where it occurs.
Beautify (Format) adds indentation and line breaks so the structure is easy to read, using your chosen 2-space, 4-space, or tab indent. Minify does the opposite — it strips every space and newline to produce the smallest possible single-line output. Use beautify when reading or debugging, and minify when you need a compact payload for an API request, config file, or localStorage.
The tool parses your input with the browser's native JSON engine the moment you stop typing. If the text is well-formed, the status bar turns green and shows 'Valid JSON' along with the character and key count. If it is not, the bar turns red and reports the parser's error message, including the position where parsing failed, so you can jump straight to the broken spot.
Yes. Because processing happens locally with no upload, the only limit is your device's memory, and modern browsers comfortably handle documents of several megabytes. Very large files may take a moment to format, but nothing leaves your machine and there is no file-size cap imposed by a server.