server/locales/en/common.json

{
  "field": {
    "BASE_TYPE_REQUIRED": "This field is required",
    "BASE_TYPE_STRING": "This field must be a string",
    "BASE_TYPE_NUMBER": "This field must be a number",
    "BASE_TYPE_BIGINT": "This field must be a bigint",
    "BASE_TYPE_BOOLEAN": "This field must be a boolean",
    "BASE_TYPE_CHOICES": "This field must be one of ({{types}})",
    "BASE_TYPE_CLASS": "This field must be an instance of {{type}}",
    "BASE_TYPE_OBJECT": "This field must be a object",
    "BASE_TYPE_ARRAY": "This field must be an array",
    "UNKOWN_FIELD": "Unkown key: {{key}}",
    "BASE_TYPE_CONSTANT": "This field must be {{value}}",
    "EMAIL_TYPE_INVALID_EMAIL": "Not a well formed email address",
    "DATE_TYPE_PARSE": "Could not parse {{date}}. Should be ISO8601",
    "BASE_TYPE_BAD_LENGTH": "Must be between {{length}} in length"
  }
}