Format, validate and minify JSON with syntax highlighting and clear error messages that point to the exact line. Free developer tool, no upload.
The JSON Formatter & Validator beautifies messy or minified JSON into readable, indented text with syntax highlighting, and flags syntax errors with a message pointing to the exact line and character where parsing failed. It is aimed at developers debugging API responses, configuration files or data exports where a single misplaced comma or unquoted key can otherwise take a long time to spot by eye.
Alongside pretty-printing, the tool can also minify JSON down to the smallest valid representation for production use, stripping all unnecessary whitespace. Paste any JSON payload, and the validator immediately confirms whether it is syntactically valid, showing a clear, human-readable error location instead of a cryptic parser exception if something is wrong.
Instead of a generic 'invalid JSON' message, errors point to the specific line and position, making even deeply nested documents quick to debug.
Pretty-print for readability while developing, or minify for the smallest payload size in production, using the same tool.
Colour-coded keys, strings, numbers and booleans make it far easier to scan a large JSON document visually than plain monospace text.
API payloads and config files are formatted locally in the browser, which matters when the JSON contains internal identifiers or credentials.
Trailing commas after the last item, single quotes instead of double quotes, unquoted object keys, and comments are all invalid in strict JSON even though JavaScript itself tolerates similar-looking syntax. The validator catches each of these and reports where they occur.
Minify JSON for API responses and production payloads, where removing whitespace reduces bandwidth and parsing overhead. Keep pretty-printed JSON for configuration files, documentation examples and anywhere a human needs to read or edit it directly.
The formatter handles deeply nested objects and arrays correctly, indenting each level consistently, which is particularly useful for spotting missing brackets in large, deeply nested API responses that would be unreadable in their raw minified form.
Browser console JSON viewers are useful but tied to a specific request; this formatter works with any JSON text pasted from anywhere — a file, an email, a log line — without needing to trigger the original network request.
Trailing commas, single quotes instead of double quotes, unquoted keys, and comments — none of which are valid JSON even though JavaScript allows them.
For API responses and production payloads, where removing whitespace cuts size noticeably. Keep formatted JSON for config files that humans need to read.
Yes. JSON Formatter & Validator on Klipza is completely free with no account, no subscription and no watermark on your files, and there is no daily usage limit.
Processing happens locally in your browser wherever technically possible, so your files are not uploaded to a server, stored or shared with third parties.
Yes. It is fully responsive and runs in any modern browser on Android, iPhone, iPad, Windows and macOS — nothing to install.