JSON Formatter
Pretty-print and validate JSON. Runs entirely in your browser — your data stays on your device.
Common questions
Is my data sent to your servers?
No. JSON formatting runs entirely in your browser using JavaScript's built-in JSON.parse and JSON.stringify. Your data never leaves the page.
Does formatting change my data?
No. Formatting only adjusts whitespace and indentation. Your data values, key order, and structure are preserved exactly as-is.
What happens with invalid JSON?
The tool shows a clear error message with parse details. Fix the input and format again — your original input is preserved.
Is there an input size limit?
Pasted text is limited to approximately 5 million characters to keep your browser responsive. Opened .json files are subject to your plan's file size allowance.