| attribute_cannot_be_present_with | with - other attribute name | Mutually exclusive with another attribute |
| attribute_cannot_be_present_without | without - other attribute name | |
| blank | | When not present |
| greater_or_equal_to | number - min value | When not greater than or equal to number |
| does_not_exist | | When related record does not exist |
| invalid | format - regex | When has invalid format |
| greater_than | number - min value | When not > number |
| greater_than_property | property - compared property | When not > value of property |
| inclusion | in - contains permitted values | When doesn't match list of permitted values |
| invalid_car_registration_number | | When doesn't match required car registration number format |
| invalid_date | | When doesn't match date format ('YYYY:MM:DD') |
| invalid_hex_color | | When doesn't match hex color format ('#000000') |
| invalid_hour | | When doesn't match hour format ('HH:MM') |
| invalid_json | | When isn't a valid JSON |
| invalid_msisdn | | When cannot be processed as a valid MSISDN> |
| invalid_email | | |
| invalid_iso_3166_country | | When not valid ISO 3166-1 alpha-2 country code |
| invalid_iso_8601_time | | When not valid according to ISO 8601 |
| invalid_iso_639_1_language | | When not valid according to ISO 639-1 |
| less_or_equal_to | number - max value | When not less than or equal to number |
| less_than | number - max value | When not < number |
| less_than_property | property - compared property | When not > value of property |
| liquid_syntax_error | syntax_error - error description | When not valid liquid syntax |
| must_be_a_string | | |
| must_be_a_boolean | | |
| must_be_an_array | | |
| must_be_an_url | allowed_protocols - e.g ['https'] | When not a valid URL |
| must_be_a_https_url | | When not a valid HTTPS URL |
| must_be_an_array_of_objects | | |
| must_be_an_object | | |
| must_be_in_the_future | | When date is not in the future |
| must_be_in_the_past | | When date is not in the past |
| must_be_unique | | When value is not unique in some context |
| must_be_uuid | | When not a valid UUID |
| must_have_elements_of_type | type - required type | |
| not_a_number | | |
| not_an_integer | | |
| record_does_not_exist | | When related record does not exist |
| records_do_not_exist | non_existing_ids | When related records do not exist |
| size_not_match | number - exact size | When array has not exactly required number of elements |
| size_too_large | number - max size | When array has too many elements |
| size_too_small | number - min size | When array has not enough elements |
| too_short | min - min length, count - given length | When string length is too small |
| too_long | max - max length, count - given length | When string length is too large |
| taken | | When another record already uses this value |
| unpermitted_property | | |