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JSON Formatter & Validator
Beautify, validate, or minify JSON instantly in your browser. Spot syntax errors fast.
About this tool
A JSON formatter takes messy, minified, or hand-written JSON and pretty-prints it with clean indentation so it's easy to read - and tells you immediately if it's invalid. Paste your JSON, pick an indent size, and the formatted result appears beside it. Need the opposite? Switch to Minify to strip every space and newline for the smallest possible payload.
What it does
- Beautify - re-indent JSON with 2 or 4 spaces for readability.
- Validate - catch syntax errors (a trailing comma, a missing quote) with the exact parser message.
- Minify - collapse JSON to one line to save bandwidth in APIs and config files.
Why valid JSON matters
JSON is strict: keys must be double-quoted, no trailing commas are allowed, and comments aren't permitted. A single misplaced character can break an API request or a config file. This tool uses your browser's own JSON parser, so what it accepts is exactly what your code will accept - making it a reliable way to check a payload before you ship it.
Everything runs locally in your browser. Your JSON - which may contain API keys or personal data - is never uploaded. To encode a JSON string for a URL afterwards, use the URL Encoder & Decoder.
Frequently asked questions
What does a JSON formatter do?
It re-indents JSON so it is easy to read (beautify), or strips all whitespace to make it compact (minify). It also validates the JSON and reports any syntax errors.
How do I know if my JSON is valid?
Paste it in - if there is a problem, an error message appears with the reason, such as an unexpected token or a position in the text. Valid JSON formats instantly with no error.
Why is my JSON invalid?
The most common causes are trailing commas, single quotes instead of double quotes, unquoted keys, or comments - none of which are allowed in standard JSON.
What is the difference between beautify and minify?
Beautify adds line breaks and indentation for humans. Minify removes them for machines, producing the smallest valid JSON to save bandwidth.
Is my JSON uploaded to a server?
No. Formatting and validation use your browser's built-in JSON parser, so your data never leaves your device.
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