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JSON formatter & validator
Paste raw JSON to format it, minify it, or check if it's valid. Everything runs in your browser.
Output will appear here
Frequently asked questions
Does the JSON formatter send my data anywhere?
No. The JSON formatter runs entirely in your browser using native JavaScript. Your data never leaves your device and no network requests are made when you paste or format JSON. This makes it safe to use with sensitive configuration files or API responses.
What is the difference between format and minify?
Formatting adds consistent indentation (two spaces by default) and line breaks to make JSON human-readable. Minifying removes all unnecessary whitespace to produce the smallest possible file size — typically used for production API responses and configuration payloads where bytes matter. A formatted JSON object might be 400 bytes; the same object minified might be 180 bytes.
Why does my JSON fail to validate even though it looks correct?
The most common causes are trailing commas (valid in JavaScript but not in JSON), single quotes instead of double quotes around keys or strings, unquoted keys, and comments (JSON does not support comments). The validator shows the exact line and character where the parse error occurs.
Can I format very large JSON files?
Yes, for files up to a few megabytes the browser formatter handles them smoothly. For very large JSON files (tens of megabytes or larger), browser-based tools can become slow. In those cases, command-line tools like jq or the built-in JSON.stringify in Node.js are more efficient.
About this tool
This JSON formatter processes everything locally in your browser using the native JSON.parse and JSON.stringify APIs — no data is ever sent to a server.
Format pretty-prints JSON with 2-space indentation, making nested objects and arrays easy to read. Minify removes all whitespace to produce the most compact valid JSON string. Validate checks whether the input is valid JSON without changing the output.
Common use cases: inspecting API responses, cleaning up copied JSON, reducing payload size, and debugging data structures.
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