JSON to PHP Array

No. This produces a single PHP statement (an assignment or a define() call) meant to be pasted into existing PHP code, not a standalone file - add your own opening tag if you save it as its own .php file.

No, and this is a JavaScript limitation, not a choice: JSON.parse collapses 1.0 and 1 to the identical JS number 1 before this tool ever sees it, so both render as the PHP int 1. If you need a literal float, write a fractional value like 1.5, or add a decimal place PHP will keep, e.g. 1.1.

They lose precision. JSON numbers are parsed with JSON.parse into ordinary JavaScript doubles, which cannot represent every integer exactly past Number.MAX_SAFE_INTEGER (9,007,199,254,740,991) - this is the same limitation every JSON tool in this toolbox that uses JSON.parse has. Keep huge IDs as JSON strings if you need them exact.

No - it is PHP's own reserved-word rule. The tool uppercases your name to build the constant, so the default "array" becomes the constant ARRAY, and `array` is a reserved keyword in PHP regardless of case, so a bare ARRAY token elsewhere in your code will not resolve to it. define('ARRAY', ...) itself is perfectly valid and the constant is set; fetch it with constant('ARRAY') instead of the bare word, or pick a different variable name before switching to Constant wrap.