JSON Formatter

Format, validate, and minify JSON

JSON (JavaScript Object Notation) is the most common format for sending data between apps and APIs. Raw JSON from a server is often a single unreadable line; this tool pretty-prints it with clean indentation so you can read and debug it, validates that it's well-formed, and can minify it back to the smallest size for production.

What it does

• Format — re-indents the JSON (2 spaces, 4 spaces, or tabs) for readability.
• Minify — strips all whitespace to shrink payload size.
• Validate — if the JSON is broken, you get the exact parse error and position.

It runs entirely in your browser, so even sensitive data never leaves your device.

FAQ

Why does my JSON say "invalid"?

Common causes: trailing commas, single quotes instead of double quotes, unquoted keys, or comments (standard JSON doesn't allow them). The error message points to where parsing failed.

Is this JSON formatter free, and is my data private?

Yes — it's free with no sign-up, and the parsing, formatting, and minifying all happen in your browser. Your JSON is never uploaded to a server, so it's safe to paste in API responses or configuration that contains sensitive values.

What's the difference between formatting and minifying?

Formatting (pretty-printing) re-indents the JSON with line breaks so a human can read and debug it. Minifying does the opposite — it strips every unnecessary space and newline to make the file as small as possible, which is what you want for production payloads where size and speed matter.

Can it handle very large JSON files?

It handles sizable documents since the work is done by your browser's native JSON engine, which is fast. Extremely large files (many megabytes) may feel slow because everything is processed in memory on your device, but typical API responses format instantly.

Does it support JSON with comments or trailing commas?

No, because standard JSON doesn't allow them, so the validator will flag them as errors. If your file uses comments or trailing commas (sometimes called JSON5 or JSONC), remove them first or the parse will fail.

Does it work on mobile?

Yes. The formatter is responsive and runs in any modern mobile browser, so you can tidy up or validate JSON on a phone or tablet without installing anything.