user1491636 user1491636 - 3 months ago 8
JSON Question

Are booleans valid JSON

Why do some JSON validators flag a boolean value as invalid JSON, and others as valid? That is, just

true
or
false
values (no object).

Valid:



Invalid:


Answer

The validator you link to validates the JSON string existing of a mere true as invalid according to RFC 4627, which dictates that the root of a JSON string is to be an array or object:

A JSON text is a serialized object or array.

 JSON-text = object / array

An unwrapped value such as true or "foo" or 42 is not JSON according to that RFC.

The other RFC it can validate against, RFC 7159, deems the above examples valid as it does not constrain a JSON text to objects or arrays, but also allows values:

A JSON value MUST be an object, array, number, or string, or one of the following three literal names:

 false null true

And because the former (RFC 4627) is obsoleted by the latter (RFC 7159), true is a valid JSON string.