JSON Formatter
Your data never leaves your device — validation and formatting happen entirely in your browser.
Why this formatter is different
Most online formatters parse your JSON into JavaScript values and print them back. That silently corrupts data: digits beyond 15–17 significant figures are lost (IDs like 12345678901234567890 come back wrong), 1e999 turns into null, and escape sequences get rewritten. This tool reformats at the token level instead — every number, string and literal comes out byte-for-byte as it went in. Only the whitespace changes.
Validation with real positions
Malformed input is refused with the exact line and column of the first problem — a missing colon, a trailing comma, an unterminated string — so you can fix it instead of guessing.
Privacy
JSON often contains credentials, tokens or customer data. Pasting it into a site that uploads to a server is a leak. Here the page is static, there is no server to receive anything, and the tool keeps working with the network disconnected — our automated tests verify that on every release.