JSON Formatter & Validator
Format, minify and validate JSON instantly with clear error messages that point at the exact problem.
JSON Formatter & Validator is the quickest way to clean up, check and minify JSON. Paste any JSON payload — from an API response, a config file or a log export — and this tool will validate it in real time and reformat it with clean two-space indentation, or compress it down to a single line for storage and network payloads.
When your JSON is invalid, the tool doesn't just say 'error': it tells you exactly where the problem is with the line and column number and a description of what went wrong, so you can fix it in seconds. This makes it ideal for debugging copy-pasted configs, verifying responses while building an API, or teaching yourself the JSON syntax.
Everything happens locally in your browser — your data is never sent to a server. That makes the tool safe to use with production configs, internal API payloads or anything else you do not want leaving your machine. It works for any JSON size your browser can comfortably handle.
Tip: use the sample button to load valid and broken examples, then experiment with the Format and Minify buttons to see how the output changes.
How to use the JSON Formatter & Validator
- Paste your JSON into the input box, or click 'Load sample' to try it with example data.
- The tool validates the input as you type and flags syntax errors with the line and column position.
- Click 'Format' to pretty-print the JSON with two-space indentation, or 'Minify' to compress it into a single compact line.
- Click 'Copy' to put the formatted or minified result on your clipboard.
- Click 'Clear' to start over with a fresh input.
Frequently asked questions
What does this JSON formatter do?
It validates that your text is syntactically correct JSON and then reformats it in two ways: Format pretty-prints it with indentation so humans can read it easily, and Minify removes all unnecessary whitespace to produce the smallest valid representation — useful for storage and for reducing request/response sizes.
How do I fix a 'Unexpected token' error?
The error message includes the line and column where parsing stopped. Look at that position — the usual culprits are a missing comma between properties, an extra trailing comma, mismatched quotes, or a single quote used instead of double quotes (JSON only allows double quotes for strings).
Is my JSON sent to a server?
No. Validation, formatting and minification are all performed locally in your browser using the standard JavaScript JSON parser. Nothing you paste is uploaded, logged or stored anywhere, which makes this tool safe for sensitive or proprietary data.
Does it handle very large JSON files?
The tool works with any input your browser can handle in memory. For typical API responses and configuration files (a few megabytes) it is instant. Extremely large files can slow down the browser, which is a limitation of any purely client-side tool.
Is there a limit on how often I can use it?
No. MaxTools is free to use as often as you need — there is no account, no daily quota and no watermark. The site is supported by unobtrusive advertising only.
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