JSON Formatter & Validator

Why format JSON in the browser?

Nothing you paste here is ever sent to a server — see why that matters. It also catches common mistakes — trailing commas, unquoted keys, mismatched brackets — and tells you roughly which line the problem is on, instead of just failing silently.

FAQ

Why does it reject JSON that looks fine?

The most common cause is that the input isn't actually valid JSON (per RFC 8259) even though it looks like a JavaScript object literal. JSON doesn't allow trailing commas, single-quoted strings, unquoted keys, or comments — all valid in JS, none valid in JSON. If a paste from your own code fails here, that's usually the reason.

What's the difference between format and minify?

Format adds indentation and line breaks so a human can read the structure. Minify strips all of that whitespace to produce the smallest possible payload — useful when you need to paste JSON into something with a size limit, or want a stable single-line string to diff.

Does this validate against a JSON Schema?

No. This checks that the input is syntactically valid JSON, not that it matches a particular shape or set of required fields — that's a separate concern (JSON Schema validation) this tool doesn't attempt.

Is there a size limit?

No limit is enforced by the tool itself, but parsing happens synchronously on the main thread via JSON.parse, so extremely large documents (tens of megabytes) may briefly freeze the tab — the same constraint any browser-based JSON tool has.