On 11/13/13 3:47 PM, "John Cowan" <cowan@xxxxxxxxxxxxxxxx> wrote: >It's not clear that 404 disallows it, since 404 is defined in terms of >characters, and a BOM is not a character but an out-of-band signal. Agree. However, that signal would be a part of the 4627bis octet stream, so a little interop guidance would likely be useful. Something like: "Some producers of JSON produce JSON-text that starts with a redundant U+FEFF (ZERO WIDTH NO-BREAK SPACE, previously known as BYTE ORDER MARK) with the ostensible purpose of signaling the encoding of the text to follow. Since JSON has other mechanisms to determine encoding, this is not required. Receiving applications MAY safely ignore this initial character without generating an error. Implementations that do not send U+FEFF are interoperable in the sense that all software implementations which receive the un-prefixed text will not generate parse errors." -- Joe Hildebrand