Is my JSON sent to a server?

No. This formatter runs entirely in your browser using the built-in JSON parser. Nothing you paste is uploaded, logged, or stored — you can disconnect from the internet and it still works.

Why does my JSON say "Unexpected token"?

That error means the parser hit a character it did not expect for valid JSON — usually a trailing comma, a single quote instead of a double quote, an unquoted key, or a missing bracket. The status line shows the line and column so you can jump straight to it.

What is the difference between formatting and minifying?

Formatting (pretty-printing) adds indentation and line breaks so JSON is readable. Minifying strips all optional whitespace to make the payload as small as possible for transport. Both produce the same data.

Does formatting change my data?

No. Formatting only changes whitespace and key ordering is preserved as written. The parsed values are identical; only the presentation changes.

Can it handle large files?

Yes, within your browser's memory. Because everything is local there is no upload limit, but very large files (tens of MB) may be slow to render in the output pane.

Is JSON the same as a JavaScript object?

They look similar but are not identical. JSON requires double-quoted keys and strings, forbids trailing commas, comments, and functions, and supports a limited set of value types. Valid JSON is a subset of JavaScript object literal syntax.

JSON Formatter & Validator

A JSON formatter takes raw, unreadable JSON and pretty-prints it with clean indentation — or minifies it back down — while validating the syntax and pointing to the exact line and column of any error. The tool above does all of this in your browser: paste JSON on the left, get formatted output on the right, and copy or download the result. Nothing you paste is transmitted anywhere.

What is JSON?

JSON (JavaScript Object Notation) is a lightweight, text-based format for storing and exchanging structured data. It is the default language of web APIs, configuration files, and countless data pipelines because it is human-readable and maps cleanly onto the data structures used by almost every programming language: objects (key–value maps), arrays, strings, numbers, booleans, and null.

A small JSON document looks like this:

{
  "name": "QuikConsole",
  "tools": 24,
  "clientSide": true,
  "tags": ["json", "dev", "privacy"]
}

What does a JSON formatter do?

Raw JSON from an API response or a log line often arrives on a single line with no whitespace. That is efficient to transmit but painful to read. A formatter parses the text, confirms it is valid, and re-serialises it with consistent indentation so the structure is obvious at a glance. Minifying does the reverse — it removes every optional space and newline to shrink the payload for storage or transport.

Common JSON errors and how to fix them

Trailing commas — JSON does not allow a comma after the last item in an object or array. Remove it.
Single quotes — keys and strings must use double quotes. 'name' is invalid; "name" is correct.
Unquoted keys — every key must be a quoted string, unlike a JavaScript object literal.
Comments — standard JSON has no comment syntax. Strip // and /* */ before parsing.
Mismatched brackets — a missing } or ] is the most common cause of an “Unexpected end of input” error.

When the parser fails, the status line reports the line and column so you can go straight to the problem rather than hunting through the whole document.

Common use cases

Reading an API response that arrived minified on one line.
Validating a config file (package.json, tsconfig.json, CI manifests) before committing.
Minifying JSON to reduce payload size before embedding it somewhere.
Diffing two JSON documents by formatting both with the same indentation first.

Is it safe to paste sensitive JSON here?

Yes — this tool never sends your input anywhere. The formatting and validation happen with the browser’s native parser, on your device. There is no server round-trip, no logging, and no third-party analytics on this page. That said, treat any online tool with healthy caution: for the most sensitive payloads, our source is open so you can verify the behaviour yourself, or run the tool offline once the page has loaded.

JSON vs YAML vs a JavaScript object

JSON is strict and unambiguous, which makes it ideal for machine-to-machine exchange. YAML is more human-friendly for configuration but whitespace-sensitive and easier to get subtly wrong. A JavaScript object literal is more permissive than JSON — it allows single quotes, trailing commas, comments, and unquoted keys — which is exactly why pasting a JS object into a strict JSON parser often fails. When in doubt, format here first to confirm validity.