How do I know where the error is?

When the JSON is invalid you get the parser’s message, which usually points to the position of the problem: a missing comma, an extra comma at the end, single quotes instead of double quotes or a missing bracket.

What is the difference between formatting and minifying?

Formatting adds indentation and line breaks to make it readable. Minifying removes every unnecessary space to make the file as small as possible for production.

Is my data sent to a server?

No. Parsing happens in your browser with the native JSON engine, so you can paste API responses or configuration with confidence.

Can it handle large files?

Several megabytes without problems; the limit is your device’s memory.

No, it keeps the original order of the keys, which is what most APIs and configuration files expect.

Yes. There is no sign-up, no watermark and no daily limit. The site is funded by a few unobtrusive ads around the tools, never inside your files.

JSON formatter

Paste your JSON and press “Format” to indent it, “Minify” to compact it or “Validate” to check it. Copy or download the result; nothing is sent anywhere.

Free, no sign-up and no uploads: processing happens in your browser · Updated September 18, 2026

Input JSON

Readable API responses

Turn a one-line API response into an indented structure you can actually read and spot errors instantly.

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Frequently asked questions

How do I know where the error is?: When the JSON is invalid you get the parser’s message, which usually points to the position of the problem: a missing comma, an extra comma at the end, single quotes instead of double quotes or a missing bracket.
What is the difference between formatting and minifying?: Formatting adds indentation and line breaks to make it readable. Minifying removes every unnecessary space to make the file as small as possible for production.
Is my data sent to a server?: No. Parsing happens in your browser with the native JSON engine, so you can paste API responses or configuration with confidence.
Can it handle large files?: Several megabytes without problems; the limit is your device’s memory.
Does it sort keys?: No, it keeps the original order of the keys, which is what most APIs and configuration files expect.
Is it really free?: Yes. There is no sign-up, no watermark and no daily limit. The site is funded by a few unobtrusive ads around the tools, never inside your files.