Tool StudioFormat, validate, and beautify JSON instantly
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Type or paste JSON into the input — the formatted result updates live as you type.
Fix, browse, or search
Auto-fix broken JSON, switch to Tree view to browse the structure, or search either panel.
Copy or download
Copy the formatted result with one click, or download it as a .json file.
Paste or type JSON and see it formatted instantly — no need to click a button after every edit, the output updates live as you type. Switch to Tree view to browse the structure as collapsible nodes instead of raw text, useful for scanning a large or deeply nested response without scrolling through walls of text.
If your JSON is broken — a missing bracket, a stray trailing comma, an unquoted key, single quotes instead of double — Auto-fix repairs the common mistakes in one click, and you can undo it instantly if the result isn't what you expected. It's best-effort, not a full JSON5 parser: a genuinely ambiguous issue, like a missing closing quote on a string, still needs a manual look, and this tool tells you plainly when that's the case rather than leaving you guessing.
This also catches a mistake that JSON parsers hide silently: if your JSON has the same key twice inside one object, only the last one survives — every JSON parser works this way, including this tool's — and it's easy to lose data without realizing it. A warning flags duplicate keys when found, so you can catch it before it costs you something.
Search works on both the input and the formatted output, so you don't need to scroll through a long document by eye.
Everything runs entirely in your browser — nothing is uploaded, and no account is needed. This tool validates JSON syntax and repairs common formatting mistakes; it doesn't validate against a JSON Schema or convert other formats, like CSV or plain text, into JSON.
A JSON formatter takes JSON data and rewrites it with consistent indentation and line breaks (or strips that out entirely to minify it), making it easier to read, edit, or compare — without changing the underlying data.
A JSON viewer displays JSON as a browsable, collapsible tree of nodes instead of raw text — useful for scanning a large or deeply nested structure without reading every line. Switch to Tree view above to use this tool's viewer instead of the text editor.
Paste or type its contents into the input above — the formatted result appears automatically as you type, no button required.
Yes, with a plugin like JSONView or JSTool installed — but if you don't already have Notepad++ set up for it, pasting into this tool is faster and needs nothing installed.
Yes — you'll get a clear error pointing at the exact syntax issue, plus an Auto-fix button that repairs the most common mistakes (trailing commas, unquoted keys, single quotes, missing colons, broken brackets) in one click.
No — it's best-effort, not a full parser. A missing closing quote in particular can't be safely guessed at, since a real JSON string is allowed to contain colons and commas. If Auto-fix can't fully repair something, it says so plainly instead of leaving you guessing, and you can undo the attempt with one click.
If the same key appears twice inside one object, only the last occurrence survives — this is standard behavior for every JSON parser, including the one this tool uses, not a bug here. A warning flags duplicate keys when found so you don't lose data without noticing.
No — all formatting, validation, and repair happen locally in your browser. Nothing is uploaded, and no account is needed.
No — this checks that your JSON is syntactically valid, not that it matches a particular schema's structure or field types. Schema validation is a separate, more specialized job than this tool covers.
No — this tool formats and repairs JSON you already have; it doesn't convert other formats into JSON.
JSON was deliberately kept minimal as a data-interchange format, not a config language — trailing commas and comments were left out of the spec entirely, which is why a comma after the last item or a // note causes a parse error here even though many programming languages allow it.
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