Laravel 5 Validation - Return as json / ajax

You can use $validator->messages() that returns an array which contains all the information about the validator, including errors. The json function takes the array and encodes it as a json string.

if ($validator->fails()) {    
    return response()->json($validator->messages(), Response::HTTP_BAD_REQUEST);
}

Note: In case of validation errors, It's better not to return response code 200. You can use other status codes like 400 or Response::HTTP_BAD_REQUEST

You can also tell Laravel you want a JSON response. Add this header to your request:

'Accept: application/json'

And Laravel will return a JSON response.