Trailing commas and single quotes are the most common causes of invalid JSON.

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Paste JSON to check it's valid. Errors show the exact line and column, with a hint for common mistakes.

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Paste JSON to start. Errors show the line and column.

Good to know: Trailing commas and single quotes are the most common causes of invalid JSON.
Does my data leave my device?: No. Everything you paste or open is processed in your browser and stays on your device.
Does it work offline?: Yes. Once this page has loaded, it keeps working without an internet connection.