JSON Formatter & Validator
Pretty-print, minify, and validate JSON data. Everything runs in your browser.
How to Use JSON Formatter & Validator
Format, minify, and validate JSON data instantly in your browser. Pretty-print with indentation, detect errors, and copy results. 100% client-side.
Type directly into the input field, paste from your clipboard, or upload a file. The tool accepts a wide range of inputs and handles edge cases automatically.
Click the action button or watch as the tool processes your input in real time. All computation happens locally in your browser - nothing is sent to any server.
Copy the output to your clipboard with one click, or download it as a file. Your data stays private throughout the entire process.
Why Choose PrivConvert?
Unlike other online tools that upload your files to remote servers, store them for days, and may use them for AI training or data mining, PrivConvert was built with privacy as the foundation.
Files are processed in volatile memory (RAM) and immediately purged. Nothing is ever written to disk or backed up.
All uploads and downloads are encrypted with TLS 1.3. Your files cannot be intercepted in transit.
Use any tool instantly without signing up, providing an email, or creating a profile. No tracking cookies, no user profiling.
Compatible with Windows, macOS, Linux, iOS, and Android. No plugins or desktop software needed - just a modern web browser.
Trusted by Thousands of Users
PrivConvert processes thousands of file conversions every day. Our commitment to privacy and security has made us the go-to choice for professionals, developers, and privacy-conscious users worldwide.
Frequently Asked Questions
Is JSON Formatter & Validator free to use?
Yes, completely free with no limits, no sign-up, and no hidden fees. Use it as many times as you want.
Is my data safe?
All processing happens directly in your browser. Your data is never sent to any server, never stored, and never shared. It's 100% client-side.
Does it work on mobile devices?
Yes. The tool works on any device with a modern web browser - smartphones, tablets, laptops, and desktops.
Do I need to create an account?
No. You can use the tool instantly without signing up, providing an email, or creating any profile.
Formatting, validating, and the errors you will actually hit
Two jobs happen here. Formatting re-indents JSON so a minified API response becomes readable. Validating tells you whether it is legal JSON at all, and where it stops being legal — usually more useful than the pretty-printing, because a parse error deep in a large document is miserable to find by eye.
The four things that are almost always wrong
- A trailing comma. Legal in JavaScript, illegal in JSON.
{"a": 1,}is a syntax error, and it is the single most common one. - Single quotes. JSON requires double quotes on both keys and
string values.
{'a': 1}is not JSON, it is a JavaScript object literal — a distinction that catches people pasting from browser consoles. - Unquoted keys.
{a: 1}is valid JavaScript and invalid JSON, for the same reason. - Comments. JSON has none.
//and/* */both fail, which is why config formats keep reinventing JSON-with-comments variants.
What JSON cannot represent
Worth knowing before you design a payload around it. There is no date type, so
dates travel as strings and ISO 8601 is the sane convention. There is no integer
type distinct from float — numbers are doubles, so integers beyond 253
lose precision, which is why large IDs are usually sent as strings. And
NaN and Infinity are not valid JSON values despite what
some serialisers emit.
Formatting happens in your browser, so payloads you are debugging — which routinely contain customer data and tokens — are not uploaded anywhere.