Format, validate, or minify JSON instantly — entirely in your browser. Nothing you paste here is ever sent to Brekzy.
JSON (JavaScript Object Notation) is a lightweight, text-based format for structuring data, built from just a few shapes: objects (key-value pairs wrapped in curly braces), arrays (ordered lists wrapped in square brackets), strings, numbers, booleans, and null. It reads naturally as text and parses cleanly in virtually every programming language, which is why it's become the default format for API responses, configuration files, and data exchanged between a browser and a server.
Formatting only rearranges whitespace and line breaks. It never changes the underlying keys, values, or data types — a formatted object still parses back to exactly the same data as the original.
Clicking Validate JSON attempts to parse your input using the browser's own JSON parser. If parsing succeeds, the tool reports that your JSON is valid without touching your input at all. If parsing fails, the browser raises a syntax error that usually names a character position where it got stuck — this tool extracts that position where it can and turns it into a plain-language message pointing you toward roughly where to look, rather than showing you a raw, unexplained stack trace.
Validation is a read-only check. It never rewrites, reformats, or attempts to repair your input — it only tells you whether it's valid JSON as written.
Formatted JSON adds indentation and line breaks so a person can scan the structure quickly — that readability is valuable while you're debugging a response, reviewing a config file, or explaining a data shape to a teammate. Minified JSON strips all of that whitespace out, collapsing everything to a single line. Neither form changes the data itself; they're the same JSON, sized differently.
The tradeoff is simple: use formatted JSON when a human needs to read it, and minified JSON when you're sending it somewhere — over an API, embedded in a URL, or bundled into a production file — and every extra byte adds to transfer size and parse time at scale.
Most invalid JSON comes down to a handful of recurring mistakes:
JSON does not allow a comma after the last item in an object or array. {"a": 1, "b": 2,} is invalid because of the comma after 2.
Every object key must be a double-quoted string. {a: 1} is invalid; it needs to be {"a": 1}.
JSON strings must use double quotes. {'a': 'b'} is invalid JSON even though it's valid in some other languages; it needs to be {"a": "b"}.
Every { needs a matching }, and every [ needs a matching ]. A missing or extra bracket anywhere in a large, deeply nested payload is one of the easiest mistakes to make and the hardest to spot by eye — running it through a validator is usually faster than counting brackets manually.
No. Everything happens locally in your browser using JavaScript's built-in JSON.parse and JSON.stringify. Your JSON is never sent to Brekzy or to any other server.
Yes. Formatting, validating, and minifying JSON on Brekzy is completely free, with no sign-up and no usage limit.
Yes. Click Validate JSON and the tool attempts to parse what you've entered, then tells you whether it's valid and, if not, roughly where the problem is.
Yes. Click Minify JSON to collapse your JSON to a single line with no extra whitespace, useful for shrinking payload size before sending it over the network.
Only when you click Format or Minify, and only in the output box -- your original input is left untouched either way. Validate never changes anything; it only checks and reports.
No. It deliberately does not try to guess at repairs like adding a missing comma or quoting a bare key. It tells you accurately whether your JSON is valid and points you toward where to look if it isn't, but fixing the syntax is left to you.
There's no hard limit enforced by the tool itself. Since parsing happens in your browser, very large payloads (tens of megabytes) may be slower depending on your device, but typical API responses and config files format instantly.
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