to help you monitor and understand yourValidation Errors
Pydantic attempts to provide useful validation errors. Below are details on common validation errors usersmay encounter when working with pydantic, together with some suggestions on how to fix them.
arguments_type¶
This error is raised when an object that would be passed as arguments to a function during validation is notatuple,list, ordict. BecauseNamedTuple uses function calls in its implementation, that is one way toproduce this error:
fromtypingimportNamedTuplefrompydanticimportBaseModel,ValidationErrorclassMyNamedTuple(NamedTuple):x:intclassMyModel(BaseModel):field:MyNamedTupletry:MyModel.model_validate({'field':'invalid'})exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'arguments_type'assertion_error¶
This error is raised when a failingassert statement is encountered during validation:
frompydanticimportBaseModel,ValidationError,field_validatorclassModel(BaseModel):x:int@field_validator('x')@classmethoddefforce_x_positive(cls,v):assertv>0returnvtry:Model(x=-1)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'assertion_error'bool_parsing¶
This error is raised when the input value is a string that is not valid for coercion to a boolean:
frompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:boolModel(x='true')# OKtry:Model(x='test')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'bool_parsing'bool_type¶
This error is raised when the input value's type is not valid for abool field:
frompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:booltry:Model(x=None)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'bool_type'This error is also raised for strict fields when the input value is not an instance ofbool.
bytes_invalid_encoding¶
This error is raised when abytes value is invalid under the configured encoding.In the following example,'a' is invalid hex (odd number of digits).
frompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:bytesmodel_config={'val_json_bytes':'hex'}try:Model(x='a')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'bytes_invalid_encoding'bytes_too_long¶
This error is raised when the length of abytes value is greater than the field'smax_length constraint:
frompydanticimportBaseModel,Field,ValidationErrorclassModel(BaseModel):x:bytes=Field(max_length=3)try:Model(x=b'test')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'bytes_too_long'bytes_too_short¶
This error is raised when the length of abytes value is less than the field'smin_length constraint:
frompydanticimportBaseModel,Field,ValidationErrorclassModel(BaseModel):x:bytes=Field(min_length=3)try:Model(x=b't')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'bytes_too_short'bytes_type¶
This error is raised when the input value's type is not valid for abytes field:
frompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:bytestry:Model(x=123)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'bytes_type'This error is also raised for strict fields when the input value is not an instance ofbytes.
callable_type¶
This error is raised when the input value is not valid as aCallable:
fromtypingimportAny,CallablefrompydanticimportBaseModel,ImportString,ValidationErrorclassModel(BaseModel):x:ImportString[Callable[[Any],Any]]Model(x='math:cos')# OKtry:Model(x='os.path')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'callable_type'fromtypingimportAnyfromcollections.abcimportCallablefrompydanticimportBaseModel,ImportString,ValidationErrorclassModel(BaseModel):x:ImportString[Callable[[Any],Any]]Model(x='math:cos')# OKtry:Model(x='os.path')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'callable_type'complex_str_parsing¶
This error is raised when the input value is a string but cannot be parsed as a complex number becauseit does not follow therule in Python:
frompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):num:complextry:# Complex numbers in json are expected to be valid complex strings.# This value `abc` is not a valid complex string.Model.model_validate_json('{"num": "abc"}')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'complex_str_parsing'complex_type¶
This error is raised when the input value cannot be interpreted as a complex number:
frompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):num:complextry:Model(num=False)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'complex_type'dataclass_exact_type¶
This error is raised when validating a dataclass withstrict=True and the input is not an instance of the dataclass:
importpydantic.dataclassesfrompydanticimportTypeAdapter,ValidationError@pydantic.dataclasses.dataclassclassMyDataclass:x:stradapter=TypeAdapter(MyDataclass)print(adapter.validate_python(MyDataclass(x='test'),strict=True))#> MyDataclass(x='test')print(adapter.validate_python({'x':'test'}))#> MyDataclass(x='test')try:adapter.validate_python({'x':'test'},strict=True)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'dataclass_exact_type'dataclass_type¶
This error is raised when the input value is not valid for adataclass field:
frompydanticimportValidationError,dataclasses@dataclasses.dataclassclassInner:x:int@dataclasses.dataclassclassOuter:y:InnerOuter(y=Inner(x=1))# OKtry:Outer(y=1)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'dataclass_type'date_from_datetime_inexact¶
This error is raised when the inputdatetime value provided for adate field has a nonzero time component.For a timestamp to parse into a field of typedate, the time components must all be zero:
fromdatetimeimportdate,datetimefrompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:dateModel(x='2023-01-01')# OKModel(x=datetime(2023,1,1))# OKtry:Model(x=datetime(2023,1,1,12))exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'date_from_datetime_inexact'date_from_datetime_parsing¶
This error is raised when the input value is a string that cannot be parsed for adate field:
fromdatetimeimportdatefrompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:datetry:Model(x='XX1494012000')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'date_from_datetime_parsing'date_future¶
This error is raised when the input value provided for aFutureDate field is not in the future:
fromdatetimeimportdatefrompydanticimportBaseModel,FutureDate,ValidationErrorclassModel(BaseModel):x:FutureDatetry:Model(x=date(2000,1,1))exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'date_future'date_parsing¶
This error is raised when validating JSON where the input value is string that cannot be parsed for adate field:
importjsonfromdatetimeimportdatefrompydanticimportBaseModel,Field,ValidationErrorclassModel(BaseModel):x:date=Field(strict=True)try:Model.model_validate_json(json.dumps({'x':'1'}))exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'date_parsing'date_past¶
This error is raised when the value provided for aPastDate field is not in the past:
fromdatetimeimportdate,timedeltafrompydanticimportBaseModel,PastDate,ValidationErrorclassModel(BaseModel):x:PastDatetry:Model(x=date.today()+timedelta(1))exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'date_past'date_type¶
This error is raised when the input value's type is not valid for adate field:
fromdatetimeimportdatefrompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:datetry:Model(x=None)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'date_type'This error is also raised for strict fields when the input value is not an instance ofdate.
datetime_from_date_parsing¶
This error is raised when the input value is a string that cannot be parsed for adatetime field:
fromdatetimeimportdatetimefrompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:datetimetry:# there is no 13th monthModel(x='2023-13-01')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'datetime_from_date_parsing'datetime_future¶
This error is raised when the value provided for aFutureDatetime field is not in the future:
fromdatetimeimportdatetimefrompydanticimportBaseModel,FutureDatetime,ValidationErrorclassModel(BaseModel):x:FutureDatetimetry:Model(x=datetime(2000,1,1))exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'datetime_future'datetime_object_invalid¶
This error is raised when something about thedatetime object is not valid:
fromdatetimeimportdatetime,tzinfofrompydanticimportAwareDatetime,BaseModel,ValidationErrorclassCustomTz(tzinfo):# utcoffset is not implemented!deftzname(self,_dt):return'CustomTZ'classModel(BaseModel):x:AwareDatetimetry:Model(x=datetime(2023,1,1,tzinfo=CustomTz()))exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'datetime_object_invalid'datetime_parsing¶
This error is raised when the value is a string that cannot be parsed for adatetime field:
importjsonfromdatetimeimportdatetimefrompydanticimportBaseModel,Field,ValidationErrorclassModel(BaseModel):x:datetime=Field(strict=True)try:Model.model_validate_json(json.dumps({'x':'not a datetime'}))exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'datetime_parsing'datetime_past¶
This error is raised when the value provided for aPastDatetime field is not in the past:
fromdatetimeimportdatetime,timedeltafrompydanticimportBaseModel,PastDatetime,ValidationErrorclassModel(BaseModel):x:PastDatetimetry:Model(x=datetime.now()+timedelta(100))exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'datetime_past'datetime_type¶
This error is raised when the input value's type is not valid for adatetime field:
fromdatetimeimportdatetimefrompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:datetimetry:Model(x=None)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'datetime_type'This error is also raised for strict fields when the input value is not an instance ofdatetime.
decimal_max_digits¶
This error is raised when the value provided for aDecimal has too many digits:
fromdecimalimportDecimalfrompydanticimportBaseModel,Field,ValidationErrorclassModel(BaseModel):x:Decimal=Field(max_digits=3)try:Model(x='42.1234')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'decimal_max_digits'decimal_max_places¶
This error is raised when the value provided for aDecimal has too many digits after the decimal point:
fromdecimalimportDecimalfrompydanticimportBaseModel,Field,ValidationErrorclassModel(BaseModel):x:Decimal=Field(decimal_places=3)try:Model(x='42.1234')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'decimal_max_places'decimal_parsing¶
This error is raised when the value provided for aDecimal could not be parsed as a decimal number:
fromdecimalimportDecimalfrompydanticimportBaseModel,Field,ValidationErrorclassModel(BaseModel):x:Decimal=Field(decimal_places=3)try:Model(x='test')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'decimal_parsing'decimal_type¶
This error is raised when the value provided for aDecimal is of the wrong type:
fromdecimalimportDecimalfrompydanticimportBaseModel,Field,ValidationErrorclassModel(BaseModel):x:Decimal=Field(decimal_places=3)try:Model(x=[1,2,3])exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'decimal_type'This error is also raised for strict fields when the input value is not an instance ofDecimal.
decimal_whole_digits¶
This error is raised when the value provided for aDecimal has more digits before the decimal point thanmax_digits -decimal_places (as long as both are specified):
fromdecimalimportDecimalfrompydanticimportBaseModel,Field,ValidationErrorclassModel(BaseModel):x:Decimal=Field(max_digits=6,decimal_places=3)try:Model(x='12345.6')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'decimal_whole_digits'default_factory_not_called¶
This error is raised when adefault factory taking validated datacan't be called, because validation failed on previous fields:
frompydanticimportBaseModel,Field,ValidationErrorclassModel(BaseModel):a:int=Field(gt=10)b:int=Field(default_factory=lambdadata:data['a'])try:Model(a=1)exceptValidationErrorasexc:print(exc)""" 2 validation errors for Model a Input should be greater than 10 [type=greater_than, input_value=1, input_type=int] b The default factory uses validated data, but at least one validation error occurred [type=default_factory_not_called] """print(repr(exc.errors()[1]['type']))#> 'default_factory_not_called'dict_type¶
This error is raised when the input value's type is notdict for adict field:
frompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:dicttry:Model(x=['1','2'])exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'dict_type'enum¶
This error is raised when the input value does not exist in anenum field members:
fromenumimportEnumfrompydanticimportBaseModel,ValidationErrorclassMyEnum(str,Enum):option='option'classModel(BaseModel):x:MyEnumtry:Model(x='other_option')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'enum'extra_forbidden¶
This error is raised when the input value contains extra fields, butmodel_config['extra'] == 'forbid':
frompydanticimportBaseModel,ConfigDict,ValidationErrorclassModel(BaseModel):x:strmodel_config=ConfigDict(extra='forbid')try:Model(x='test',y='test')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'extra_forbidden'You can read more about theextra configuration in theExtra Attributes section.
finite_number¶
This error is raised when the value is infinite, or too large to be represented as a 64-bit floating point numberduring validation:
frompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:inttry:Model(x=2.2250738585072011e308)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'finite_number'float_parsing¶
This error is raised when the value is a string that can't be parsed as afloat:
frompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:floattry:Model(x='test')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'float_parsing'float_type¶
This error is raised when the input value's type is not valid for afloat field:
frompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:floattry:Model(x=None)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'float_type'frozen_field¶
This error is raised when you attempt to assign a value to a field withfrozen=True, or to delete such a field:
frompydanticimportBaseModel,Field,ValidationErrorclassModel(BaseModel):x:str=Field('test',frozen=True)model=Model()try:model.x='test1'exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'frozen_field'try:delmodel.xexceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'frozen_field'frozen_instance¶
This error is raised whenfrozen is set in theconfiguration and you attempt to delete or assign a new value toany of the fields:
frompydanticimportBaseModel,ConfigDict,ValidationErrorclassModel(BaseModel):x:intmodel_config=ConfigDict(frozen=True)m=Model(x=1)try:m.x=2exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'frozen_instance'try:delm.xexceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'frozen_instance'frozen_set_type¶
This error is raised when the input value's type is not valid for afrozenset field:
frompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:frozensettry:model=Model(x='test')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'frozen_set_type'get_attribute_error¶
This error is raised whenmodel_config['from_attributes'] == True and an error is raised while reading the attributes:
frompydanticimportBaseModel,ConfigDict,ValidationErrorclassFoobar:def__init__(self):self.x=1@propertydefy(self):raiseRuntimeError('intentional error')classModel(BaseModel):x:inty:strmodel_config=ConfigDict(from_attributes=True)try:Model.model_validate(Foobar())exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'get_attribute_error'greater_than¶
This error is raised when the value is not greater than the field'sgt constraint:
frompydanticimportBaseModel,Field,ValidationErrorclassModel(BaseModel):x:int=Field(gt=10)try:Model(x=10)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'greater_than'greater_than_equal¶
This error is raised when the value is not greater than or equal to the field'sge constraint:
frompydanticimportBaseModel,Field,ValidationErrorclassModel(BaseModel):x:int=Field(ge=10)try:Model(x=9)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'greater_than_equal'int_from_float¶
This error is raised when you provide afloat value for anint field:
frompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:inttry:Model(x=0.5)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'int_from_float'int_parsing¶
This error is raised when the value can't be parsed asint:
frompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:inttry:Model(x='test')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'int_parsing'int_parsing_size¶
This error is raised when attempting to parse a python or JSON value from a string outside the maximum range that Pythonstr toint parsing permits:
importjsonfrompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:int# from PythonassertModel(x='1'*4_300).x==int('1'*4_300)# OKtoo_long='1'*4_301try:Model(x=too_long)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'int_parsing_size'# from JSONtry:Model.model_validate_json(json.dumps({'x':too_long}))exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'int_parsing_size'int_type¶
This error is raised when the input value's type is not valid for anint field:
frompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:inttry:Model(x=None)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'int_type'invalid_key¶
This error is raised when attempting to validate adict that has a key that is not an instance ofstr:
frompydanticimportBaseModel,ConfigDict,ValidationErrorclassModel(BaseModel):x:intmodel_config=ConfigDict(extra='allow')try:Model.model_validate({'x':1,b'y':2})exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'invalid_key'is_instance_of¶
This error is raised when the input value is not an instance of the expected type:
frompydanticimportBaseModel,ConfigDict,ValidationErrorclassNested:x:strclassModel(BaseModel):y:Nestedmodel_config=ConfigDict(arbitrary_types_allowed=True)try:Model(y='test')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'is_instance_of'is_subclass_of¶
This error is raised when the input value is not a subclass of the expected type:
frompydanticimportBaseModel,ValidationErrorclassNested:x:strclassModel(BaseModel):y:type[Nested]try:Model(y='test')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'is_subclass_of'iterable_type¶
This error is raised when the input value is not valid as anIterable:
fromcollections.abcimportIterablefrompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):y:Iterable[str]try:Model(y=123)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'iterable_type'iteration_error¶
This error is raised when an error occurs during iteration:
frompydanticimportBaseModel,ValidationErrordefgen():yield1raiseRuntimeError('error')classModel(BaseModel):x:list[int]try:Model(x=gen())exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'iteration_error'json_invalid¶
This error is raised when the input value is not a valid JSON string:
frompydanticimportBaseModel,Json,ValidationErrorclassModel(BaseModel):x:Jsontry:Model(x='test')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'json_invalid'json_type¶
This error is raised when the input value is of a type that cannot be parsed as JSON:
frompydanticimportBaseModel,Json,ValidationErrorclassModel(BaseModel):x:Jsontry:Model(x=None)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'json_type'less_than¶
This error is raised when the input value is not less than the field'slt constraint:
frompydanticimportBaseModel,Field,ValidationErrorclassModel(BaseModel):x:int=Field(lt=10)try:Model(x=10)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'less_than'less_than_equal¶
This error is raised when the input value is not less than or equal to the field'sle constraint:
frompydanticimportBaseModel,Field,ValidationErrorclassModel(BaseModel):x:int=Field(le=10)try:Model(x=11)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'less_than_equal'list_type¶
This error is raised when the input value's type is not valid for alist field:
frompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:list[int]try:Model(x=1)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'list_type'literal_error¶
This error is raised when the input value is not one of the expected literal values:
fromtypingimportLiteralfrompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:Literal['a','b']Model(x='a')# OKtry:Model(x='c')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'literal_error'mapping_type¶
This error is raised when a problem occurs during validation due to a failure in a call to the methods from theMapping protocol, such as.items():
fromcollections.abcimportMappingfrompydanticimportBaseModel,ValidationErrorclassBadMapping(Mapping):defitems(self):raiseValueError()def__iter__(self):raiseValueError()def__getitem__(self,key):raiseValueError()def__len__(self):return1classModel(BaseModel):x:dict[str,str]try:Model(x=BadMapping())exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'mapping_type'missing¶
This error is raised when there are required fields missing from the input value:
frompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:strtry:Model()exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'missing'missing_argument¶
This error is raised when a required positional-or-keyword argument is not passed to a function decorated withvalidate_call:
frompydanticimportValidationError,validate_call@validate_calldeffoo(a:int):returnatry:foo()exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'missing_argument'missing_keyword_only_argument¶
This error is raised when a required keyword-only argument is not passed to a function decorated withvalidate_call:
frompydanticimportValidationError,validate_call@validate_calldeffoo(*,a:int):returnatry:foo()exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'missing_keyword_only_argument'missing_positional_only_argument¶
This error is raised when a required positional-only argument is not passed to a function decorated withvalidate_call:
frompydanticimportValidationError,validate_call@validate_calldeffoo(a:int,/):returnatry:foo()exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'missing_positional_only_argument'missing_sentinel_error¶
This error is raised when the experimentalMISSING sentinel is the only value allowed, and wasn'tprovided during validation:
frompydanticimportBaseModel,ValidationErrorfrompydantic.experimental.missing_sentinelimportMISSINGclassModel(BaseModel):f:MISSINGtry:Model(f=1)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'missing_sentinel_error'model_attributes_type¶
This error is raised when the input value is not a valid dictionary, model instance, or instance that fields can be extracted from:
frompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):a:intb:int# simply validating a dictprint(Model.model_validate({'a':1,'b':2}))#> a=1 b=2classCustomObj:def__init__(self,a,b):self.a=aself.b=b# using from attributes to extract fields from an objectsprint(Model.model_validate(CustomObj(3,4),from_attributes=True))#> a=3 b=4try:Model.model_validate('not an object',from_attributes=True)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'model_attributes_type'model_type¶
This error is raised when the input to a model is not an instance of the model or dict:
frompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):a:intb:int# simply validating a dictm=Model.model_validate({'a':1,'b':2})print(m)#> a=1 b=2# validating an existing model instanceprint(Model.model_validate(m))#> a=1 b=2try:Model.model_validate('not an object')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'model_type'multiple_argument_values¶
This error is raised when you provide multiple values for a single argument while calling a function decorated withvalidate_call:
frompydanticimportValidationError,validate_call@validate_calldeffoo(a:int):returnatry:foo(1,a=2)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'multiple_argument_values'multiple_of¶
This error is raised when the input is not a multiple of a field'smultiple_of constraint:
frompydanticimportBaseModel,Field,ValidationErrorclassModel(BaseModel):x:int=Field(multiple_of=5)try:Model(x=1)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'multiple_of'needs_python_object¶
This type of error is raised when validation is attempted from a format that cannot be converted to a Python object.For example, we cannot checkisinstance orissubclass from JSON:
importjsonfrompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):bm:type[BaseModel]try:Model.model_validate_json(json.dumps({'bm':'not a basemodel class'}))exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'needs_python_object'no_such_attribute¶
This error is raised whenvalidate_assignment=True in the config, and you attempt to assign a value to an attributethat is not an existing field:
frompydanticimportConfigDict,ValidationError,dataclasses@dataclasses.dataclass(config=ConfigDict(validate_assignment=True))classMyDataclass:x:intm=MyDataclass(x=1)try:m.y=10exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'no_such_attribute'none_required¶
This error is raised when the input value is notNone for a field that requiresNone:
frompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:Nonetry:Model(x=1)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'none_required'Note
You may encounter this error when there is a naming collision in your model between a field name and its type. More specifically, this error is likely to be thrown when the default value of that field isNone.
For example, the following would yield thenone_required validation error since the fieldint is set to a default value ofNone and has the exact same name as its type, which causes problems with validation.
fromtypingimportOptionalfrompydanticimportBaseModelclassM1(BaseModel):int:Optional[int]=Nonem=M1(int=123)# errorsrecursion_loop¶
This error is raised when a cyclic reference is detected:
frompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:list['Model']d={'x':[]}d['x'].append(d)try:Model(**d)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'recursion_loop'set_item_not_hashable¶
This error is raised when an unhashable value is validated against aset or afrozenset:
frompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:set[object]classUnhashable:__hash__=Nonetry:Model(x=[{'a':'b'},Unhashable()])exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'set_item_not_hashable'print(repr(exc.errors()[1]['type']))#> 'set_item_not_hashable'set_type¶
This error is raised when the value type is not valid for aset field:
frompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:set[int]try:Model(x='test')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'set_type'string_pattern_mismatch¶
This error is raised when the input value doesn't match the field'spattern constraint:
frompydanticimportBaseModel,Field,ValidationErrorclassModel(BaseModel):x:str=Field(pattern='test')try:Model(x='1')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'string_pattern_mismatch'string_sub_type¶
This error is raised when the value is an instance of a strict subtype ofstr when the field is strict:
fromenumimportEnumfrompydanticimportBaseModel,Field,ValidationErrorclassMyEnum(str,Enum):foo='foo'classModel(BaseModel):x:str=Field(strict=True)try:Model(x=MyEnum.foo)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'string_sub_type'string_too_long¶
This error is raised when the input value is a string whose length is greater than the field'smax_length constraint:
frompydanticimportBaseModel,Field,ValidationErrorclassModel(BaseModel):x:str=Field(max_length=3)try:Model(x='test')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'string_too_long'string_too_short¶
This error is raised when the input value is a string whose length is less than the field'smin_length constraint:
frompydanticimportBaseModel,Field,ValidationErrorclassModel(BaseModel):x:str=Field(min_length=3)try:Model(x='t')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'string_too_short'string_type¶
This error is raised when the input value's type is not valid for astr field:
frompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:strtry:Model(x=1)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'string_type'This error is also raised for strict fields when the input value is not an instance ofstr.
string_unicode¶
This error is raised when the value cannot be parsed as a Unicode string:
frompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:strtry:Model(x=b'\x81')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'string_unicode'time_delta_parsing¶
This error is raised when the input value is a string that cannot be parsed for atimedelta field:
fromdatetimeimporttimedeltafrompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:timedeltatry:Model(x='t')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'time_delta_parsing'time_delta_type¶
This error is raised when the input value's type is not valid for atimedelta field:
fromdatetimeimporttimedeltafrompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:timedeltatry:Model(x=None)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'time_delta_type'This error is also raised for strict fields when the input value is not an instance oftimedelta.
time_parsing¶
This error is raised when the input value is a string that cannot be parsed for atime field:
fromdatetimeimporttimefrompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:timetry:Model(x='25:20:30.400')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'time_parsing'time_type¶
This error is raised when the value type is not valid for atime field:
fromdatetimeimporttimefrompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:timetry:Model(x=None)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'time_type'This error is also raised for strict fields when the input value is not an instance oftime.
timezone_aware¶
This error is raised when thedatetime value provided for a timezone-awaredatetime fielddoesn't have timezone information:
fromdatetimeimportdatetimefrompydanticimportAwareDatetime,BaseModel,ValidationErrorclassModel(BaseModel):x:AwareDatetimetry:Model(x=datetime.now())exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'timezone_aware'timezone_naive¶
This error is raised when thedatetime value provided for a timezone-naivedatetime fieldhas timezone info:
fromdatetimeimportdatetime,timezonefrompydanticimportBaseModel,NaiveDatetime,ValidationErrorclassModel(BaseModel):x:NaiveDatetimetry:Model(x=datetime.now(tz=timezone.utc))exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'timezone_naive'too_long¶
This error is raised when the input value's length is greater than the field'smax_length constraint:
frompydanticimportBaseModel,Field,ValidationErrorclassModel(BaseModel):x:list[int]=Field(max_length=3)try:Model(x=[1,2,3,4])exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'too_long'too_short¶
This error is raised when the value length is less than the field'smin_length constraint:
frompydanticimportBaseModel,Field,ValidationErrorclassModel(BaseModel):x:list[int]=Field(min_length=3)try:Model(x=[1,2])exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'too_short'tuple_type¶
This error is raised when the input value's type is not valid for atuple field:
frompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):x:tuple[int]try:Model(x=None)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'tuple_type'This error is also raised for strict fields when the input value is not an instance oftuple.
unexpected_keyword_argument¶
This error is raised when you provide a value by keyword for a positional-onlyargument while calling a function decorated withvalidate_call:
frompydanticimportValidationError,validate_call@validate_calldeffoo(a:int,/):returnatry:foo(a=2)exceptValidationErrorasexc:print(repr(exc.errors()[1]['type']))#> 'unexpected_keyword_argument'It is also raised when using pydantic.dataclasses andextra=forbid:
frompydanticimportTypeAdapter,ValidationErrorfrompydantic.dataclassesimportdataclass@dataclass(config={'extra':'forbid'})classFoo:bar:inttry:TypeAdapter(Foo).validate_python({'bar':1,'foobar':2})exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'unexpected_keyword_argument'unexpected_positional_argument¶
This error is raised when you provide a positional value for a keyword-onlyargument while calling a function decorated withvalidate_call:
frompydanticimportValidationError,validate_call@validate_calldeffoo(*,a:int):returnatry:foo(2)exceptValidationErrorasexc:print(repr(exc.errors()[1]['type']))#> 'unexpected_positional_argument'union_tag_invalid¶
This error is raised when the input's discriminator is not one of the expected values:
fromtypingimportLiteral,UnionfrompydanticimportBaseModel,Field,ValidationErrorclassBlackCat(BaseModel):pet_type:Literal['blackcat']classWhiteCat(BaseModel):pet_type:Literal['whitecat']classModel(BaseModel):cat:Union[BlackCat,WhiteCat]=Field(discriminator='pet_type')try:Model(cat={'pet_type':'dog'})exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'union_tag_invalid'fromtypingimportLiteralfrompydanticimportBaseModel,Field,ValidationErrorclassBlackCat(BaseModel):pet_type:Literal['blackcat']classWhiteCat(BaseModel):pet_type:Literal['whitecat']classModel(BaseModel):cat:BlackCat|WhiteCat=Field(discriminator='pet_type')try:Model(cat={'pet_type':'dog'})exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'union_tag_invalid'union_tag_not_found¶
This error is raised when it is not possible to extract a discriminator value from the input:
fromtypingimportLiteral,UnionfrompydanticimportBaseModel,Field,ValidationErrorclassBlackCat(BaseModel):pet_type:Literal['blackcat']classWhiteCat(BaseModel):pet_type:Literal['whitecat']classModel(BaseModel):cat:Union[BlackCat,WhiteCat]=Field(discriminator='pet_type')try:Model(cat={'name':'blackcat'})exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'union_tag_not_found'fromtypingimportLiteralfrompydanticimportBaseModel,Field,ValidationErrorclassBlackCat(BaseModel):pet_type:Literal['blackcat']classWhiteCat(BaseModel):pet_type:Literal['whitecat']classModel(BaseModel):cat:BlackCat|WhiteCat=Field(discriminator='pet_type')try:Model(cat={'name':'blackcat'})exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'union_tag_not_found'url_parsing¶
This error is raised when the input value cannot be parsed as a URL:
frompydanticimportAnyUrl,BaseModel,ValidationErrorclassModel(BaseModel):x:AnyUrltry:Model(x='test')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'url_parsing'url_scheme¶
This error is raised when the URL scheme is not valid for the URL type of the field:
frompydanticimportBaseModel,HttpUrl,ValidationErrorclassModel(BaseModel):x:HttpUrltry:Model(x='ftp://example.com')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'url_scheme'url_syntax_violation¶
This error is raised when the URL syntax is not valid:
frompydanticimportBaseModel,Field,HttpUrl,ValidationErrorclassModel(BaseModel):x:HttpUrl=Field(strict=True)try:Model(x='http:////example.com')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'url_syntax_violation'url_too_long¶
This error is raised when the URL length is greater than 2083:
frompydanticimportBaseModel,HttpUrl,ValidationErrorclassModel(BaseModel):x:HttpUrltry:Model(x='x'*2084)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'url_too_long'url_type¶
This error is raised when the input value's type is not valid for a URL field:
frompydanticimportBaseModel,HttpUrl,ValidationErrorclassModel(BaseModel):x:HttpUrltry:Model(x=None)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'url_type'uuid_parsing¶
This error is raised when the input value's type is not valid for a UUID field:
fromuuidimportUUIDfrompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):u:UUIDtry:Model(u='12345678-124-1234-1234-567812345678')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'uuid_parsing'uuid_type¶
This error is raised when the input value's type is not valid instance for a UUID field (str, bytes or UUID):
fromuuidimportUUIDfrompydanticimportBaseModel,ValidationErrorclassModel(BaseModel):u:UUIDtry:Model(u=1234567812412341234567812345678)exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'uuid_type'uuid_version¶
This error is raised when the input value's type is not match UUID version:
frompydanticimportUUID5,BaseModel,ValidationErrorclassModel(BaseModel):u:UUID5try:Model(u='a6cc5730-2261-11ee-9c43-2eb5a363657c')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'uuid_version'value_error¶
This error is raised when aValueError is raised during validation:
frompydanticimportBaseModel,ValidationError,field_validatorclassModel(BaseModel):x:str@field_validator('x')@classmethoddefrepeat_b(cls,v):raiseValueError()try:Model(x='test')exceptValidationErrorasexc:print(repr(exc.errors()[0]['type']))#> 'value_error'