Is my JSON sent to a server?

No. The formatter runs entirely in your browser using JavaScript's built-in JSON parser. Nothing is uploaded, logged, or stored — even by us.

How big can my JSON be?

There is no fixed limit. The tool can format JSON files in the tens of megabytes; the practical ceiling is whatever your browser tab's memory allows. For very large files (100 MB+), expect a brief pause while parsing.

What does the error message tell me?

When JSON is invalid, the tool surfaces the exact position of the failure (line and column) along with the parser's message. The most common cause is a trailing comma, an unquoted key, or a single quote where a double quote was expected.

Can I sort keys alphabetically?

Yes — toggle "Sort keys" before formatting. The tool does a deep recursive sort so nested objects are sorted too. Arrays are left in their original order to preserve meaning.

What is the difference between formatting and validating?

Validation only checks that the input is well-formed JSON; formatting validates and then rewrites it with consistent indentation. Minify also validates first, then strips whitespace to produce the smallest valid representation.

Files never leave your device

JSON Formatter, Validator & Minifier

Pretty-print, minify, and validate JSON. Catches syntax errors with line and column reporting.

Indent

Sort keys

Input

Output

How to use JSON Formatter

Paste your JSON into the input area on the left.
Click "Format" to pretty-print, or "Minify" to strip whitespace.
If the JSON is invalid, you'll see a precise line-and-column error message.
Copy the result with one click, or download it as a .json file.

When you'd reach for a JSON formatter

JSON is the lingua franca of web APIs, configuration files, and structured logs. It's also painful to read when it arrives unformatted. Whether you're debugging a webhook payload, comparing two API responses, or cleaning up a copy-pasted config, a fast formatter saves real time.

Why use a browser-based formatter?

Most online JSON tools post your data to a backend. That's fine for public schemas, but JSON often contains access tokens, internal IDs, customer data, or third-party API responses you've signed an NDA over. Sending any of that to a third-party server is a needless risk. This formatter runs entirely on your machine — open the network tab and watch: zero requests fire when you click Format.

Beyond formatting

The minifier is useful when shipping JSON inside another payload (e.g. a base-64 string in a JWT, or a query parameter). The validator catches a class of bug that's easy to miss in editors that don't enforce strict JSON — a single trailing comma can break a deploy. Treat the formatter as a quick sanity check before committing config changes.