The preset contains one long integer ID, a decimal with trailing zeroes and a nested array containing booleans, null and one object. Two-space pretty printing is selected. The parser validates the entire source before showing output, records eight JSON values, two objects and one array, and reports no duplicate names. It never converts the integer or decimal to JavaScript Number.
The compact input is already valid strict JSON
The source starts with an object and contains exactly one complete value. Every name uses double quotes; commas and colons are present; the array and nested object close correctly. The long ID `900719925474099312345` follows integer grammar despite exceeding the safe JavaScript integer boundary. The ratio `1.2300` also follows decimal grammar. Successful validation means formatting may proceed, not that an external API accepts those fields.
Pretty printing changes structure whitespace only
The opening and closing braces move to separate lines. Each member receives two spaces of indentation, array items receive four, and the nested object member receives six. One space appears after each colon. There are no trailing spaces and no final line terminator. The exact tokens for the ID, `1.2300`, `true`, `null` and the escaped string remain unchanged, as does object member order.
Minifying the pretty result restores the tuple
Paste the pretty output back into the same tool and choose Minify. All permitted whitespace outside strings disappears, so the exact original compact tuple returns. This round trip is an executable check of the lossless contract. It does not compare semantic objects or reorder names. Before using the payload, still review duplicate-name count, destination schema and any range restrictions imposed by the receiving system.