(I'm using the uncompressed v1.5 download here!) It looks like the implementation of the remote method is supposed to support custom messages from the server when using the remote method but because of a trivial bug, they don't work.
This quick change fixes the problem (details below) From: 915 success: function(response) { 916 if ( response ) { 917 var submitted = validator.formSubmitted; To: 915 success: function(response) { 916 if ( response === true ) { 917 var submitted = validator.formSubmitted; Because of type coercion, we can only see whether the response is "truthy" or "falsey" from this line. If we take a look at line 924: 924 errors[element.name] = response || validator.defaultMessage ( element, "remote" ); It would seem to be checking the response and assigning that to the error message if it is truthy, but it never can be because of the coercion on line 916. Explicitly checking for true in the response allows us to provide a string as the response and automatically see this appear as the error message. This gives the remote response three possible cases: true: the validation passed false: the validation did not pass - display the default error message / message provided to the validate method <string>: the validation did not pass, display this string as the custom error Given that it's only possible to have one instance of remote on each field, this is a useful feature for systems that need to do 2 or more distinct checks on a field at the server end. Great plugin, thanks very much!