Check JSON and see exactly where it breaks
Runs in your browser. Nothing you type is sent anywhere. Updated on 24 Oct 2026.Valid JSON or not? Paste it here and the answer comes back with the exact line and column of the first problem, plus the most likely fix: a trailing comma after the last item, single quotes where JSON needs double, an unquoted key, or a stray comment copied out of a config file. Valid input is confirmed and pretty-printed, so you can check the structure at the same time.
Paste the JSON you want to check into the Input pane.
If it is invalid, read the message under the input: it gives the line, the column and the likely fix.
Correct that spot in the Input pane; the message clears once the JSON is valid.
Check the Formatted pane, which shows the valid JSON pretty-printed with its key count and depth.
This JSON formatter turns compact or messy JSON into a clean, indented document you can read, and tells you exactly where it breaks if it is not valid. Choose two spaces, four spaces or tabs, sort keys alphabetically, or minify back to a single line for production.
People use it when an API response arrives on one line, when a config file stops loading and the error message only says "unexpected token", or when two teams need the same file diffed with keys in the same order. Paste, press Ctrl+Enter, copy the result.
If validation fails you get the line and column plus a plain-English fix, such as "Remove the trailing comma" or "Property names must be wrapped in double quotes". For structured browsing, switch to the tree view and collapse what you do not need. Related tools: JSON to TypeScript, YAML to JSON, CSV to JSON.
The rest of the article, and all 6 questions about JSON Formatter & Validator, are on the JSON Formatter & Validator page.
Yes, free with no signup, no usage limit and no watermark on anything you copy or download. The site is funded by a small number of ads shown below the tool, never inside the editor, and no feature is held back for a paid plan.
No. Formatting, validation and minifying all run in your browser with JavaScript, so nothing you paste leaves your device and no copy is kept on a server. API responses holding access tokens, customer names or bank details are safe to paste here.
Paste the text and press Format. The error message shows the line and column, highlights the line, and suggests the most likely fix, for example removing a trailing comma or replacing single quotes with double quotes.
Yes. Choose 2 spaces, 4 spaces or Tab in the options bar and the output reindents as you change it. The choice is remembered on this device, so the next file comes back in the same style. Minify removes the indentation altogether for a production payload.
Still stuck? Ask about JSON Formatter & Validator and anybody who knows can answer. No account needed.
Same job, other tools: GraphQL Validator – Check a GraphQL query or schema for errors, optionally against your own SDL.
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