Conversion Table

The following table provides details on how Pydantic converts data during validation in both strict and lax modes.

The "Strict" column contains checkmarks for type conversions that are allowed when validating in Strict Mode.

AllJSONJSON - StrictPythonPython - Strict

Field Type	Input	Strict	Input Source	Conditions
bool	bool	✓	Python & JSON
bool	float		Python & JSON	Allowed values: 0.0, 1.0.
bool	int		Python & JSON	Allowed values: 0, 1.
bool	str		Python & JSON	Allowed values: 'f', 'n', 'no', 'off', 'false', 'False', 't', 'y', 'on', 'yes', 'true', 'True'.
bool	Decimal		Python	Allowed values: Decimal(0), Decimal(1).
bytes	bytearray		Python
bytes	bytes	✓	Python
bytes	str	✓	JSON
bytes	str		Python
callable	-		JSON	Never valid.
callable	Any	✓	Python	callable() check must return True.
date	bytes		Python	Format: YYYY-MM-DD (UTF-8).
date	date	✓	Python
date	datetime		Python	Must be exact date, eg. no H, M, S, f.
date	float		Python & JSON	Interpreted as seconds or ms from epoch. See speedate. Must be exact date.
date	int		Python & JSON	Interpreted as seconds or ms from epoch. See speedate. Must be exact date.
date	str		Python & JSON	Format: YYYY-MM-DD.
date	Decimal		Python	Interpreted as seconds or ms from epoch. See speedate. Must be exact date.
datetime	bytes		Python	Format: YYYY-MM-DDTHH:MM:SS.f. See speedate, (UTF-8).
datetime	date		Python
datetime	datetime	✓	Python
datetime	float		Python & JSON	Interpreted as seconds or ms from epoch, see speedate.
datetime	int		Python & JSON	Interpreted as seconds or ms from epoch, see speedate.
datetime	str		Python & JSON	Format: YYYY-MM-DDTHH:MM:SS.f. See speedate.
datetime	Decimal		Python	Interpreted as seconds or ms from epoch, see speedate.
deque	deque	✓	Python
deque	frozenset		Python
deque	list		Python
deque	set		Python
deque	tuple		Python
deque	Array	✓	JSON
dict	dict	✓	Python
dict	Mapping		Python	Must implement the mapping interface and have an items() method.
dict	Object	✓	JSON
float	bool		Python & JSON
float	bytes		Python	Must match [0-9]+(\.[0-9]+)?.
float	float	✓	Python & JSON	bool is explicitly forbidden.
float	int	✓	Python & JSON
float	str		Python & JSON	Must match [0-9]+(\.[0-9]+)?.
float	Decimal		Python
frozenset	deque		Python
frozenset	dict_keys		Python
frozenset	dict_values		Python
frozenset	frozenset	✓	Python
frozenset	list		Python
frozenset	set		Python
frozenset	tuple		Python
frozenset	Array	✓	JSON
int	bool		Python & JSON
int	bytes		Python	Must be numeric only, e.g. [0-9]+.
int	float		Python & JSON	Must be exact int, e.g. val % 1 == 0, raises error for nan, inf.
int	int	✓	Python & JSON	bool is explicitly forbidden.
int	int		Python & JSON
int	str		Python & JSON	Must be numeric only, e.g. [0-9]+.
int	Decimal		Python	Must be exact int, e.g. val % 1 == 0.
list	deque		Python
list	dict_keys		Python
list	dict_values		Python
list	frozenset		Python
list	list	✓	Python
list	set		Python
list	tuple		Python
list	Array	✓	JSON
namedtuple	dict	✓	Python
namedtuple	list	✓	Python
namedtuple	namedtuple	✓	Python
namedtuple	tuple	✓	Python
namedtuple	Array	✓	JSON
namedtuple	NamedTuple	✓	Python
set	deque		Python
set	dict_keys		Python
set	dict_values		Python
set	frozenset		Python
set	list		Python
set	set	✓	Python
set	tuple		Python
set	Array	✓	JSON
str	bytearray		Python	Assumes UTF-8, error on unicode decoding error.
str	bytes		Python	Assumes UTF-8, error on unicode decoding error.
str	str	✓	Python & JSON
time	bytes		Python	Format: HH:MM:SS.FFFFFF. See speedate.
time	float		Python & JSON	Interpreted as seconds, range 0 - 86399.9*.
time	int		Python & JSON	Interpreted as seconds, range 0 - 86399.
time	str		Python & JSON	Format: HH:MM:SS.FFFFFF. See speedate.
time	time	✓	Python
time	Decimal		Python	Interpreted as seconds, range 0 - 86399.9*.
timedelta	bytes		Python	Format: ISO8601. See speedate, (UTF-8).
timedelta	float		Python & JSON	Interpreted as seconds.
timedelta	int		Python & JSON	Interpreted as seconds.
timedelta	str		Python & JSON	Format: ISO8601. See speedate.
timedelta	timedelta	✓	Python
timedelta	Decimal		Python	Interpreted as seconds.
tuple	deque		Python
tuple	dict_keys		Python
tuple	dict_values		Python
tuple	frozenset		Python
tuple	list		Python
tuple	set		Python
tuple	tuple	✓	Python
tuple	Array	✓	JSON
Any	Any	✓	Python & JSON
ByteSize	float	✓	Python & JSON
ByteSize	int	✓	Python & JSON
ByteSize	str	✓	Python & JSON
ByteSize	Decimal	✓	Python
Decimal	float	✓	JSON
Decimal	float		Python & JSON
Decimal	int	✓	JSON
Decimal	int		Python & JSON
Decimal	str	✓	JSON
Decimal	str		Python & JSON	Must match [0-9]+(\.[0-9]+)?.
Decimal	Decimal	✓	Python
Enum	Any	✓	JSON	Input value must be convertible to enum values.
Enum	Any		Python	Input value must be convertible to enum values.
Enum	Enum	✓	Python
IPv4Address	bytes		Python
IPv4Address	int		Python	integer representing the IP address, must be less than 2**32
IPv4Address	str	✓	JSON
IPv4Address	str		Python & JSON
IPv4Address	IPv4Address	✓	Python
IPv4Address	IPv4Interface	✓	Python
IPv4Interface	bytes		Python
IPv4Interface	int		Python	integer representing the IP address, must be less than 2**32
IPv4Interface	str	✓	JSON
IPv4Interface	str		Python & JSON
IPv4Interface	tuple		Python
IPv4Interface	IPv4Address		Python
IPv4Interface	IPv4Interface	✓	Python
IPv4Network	bytes		Python
IPv4Network	int		Python	integer representing the IP network, must be less than 2**32
IPv4Network	str	✓	JSON
IPv4Network	str		Python & JSON
IPv4Network	IPv4Address		Python
IPv4Network	IPv4Interface		Python
IPv4Network	IPv4Network	✓	Python
IPv6Address	bytes		Python
IPv6Address	int		Python	integer representing the IP address, must be less than 2**128
IPv6Address	str	✓	JSON
IPv6Address	str		Python & JSON
IPv6Address	IPv6Address	✓	Python
IPv6Address	IPv6Interface	✓	Python
IPv6Interface	bytes		Python
IPv6Interface	int		Python	integer representing the IP address, must be less than 2**128
IPv6Interface	str	✓	JSON
IPv6Interface	str		Python & JSON
IPv6Interface	tuple		Python
IPv6Interface	IPv6Address		Python
IPv6Interface	IPv6Interface	✓	Python
IPv6Network	bytes		Python
IPv6Network	int		Python	integer representing the IP address, must be less than 2**128
IPv6Network	str	✓	JSON
IPv6Network	str		Python & JSON
IPv6Network	IPv6Address		Python
IPv6Network	IPv6Interface		Python
IPv6Network	IPv6Network	✓	Python
InstanceOf	-		JSON	Never valid.
InstanceOf	Any	✓	Python	isinstance() check must return True.
IntEnum	Any	✓	JSON	Input value must be convertible to enum values.
IntEnum	Any		Python	Input value must be convertible to enum values.
IntEnum	IntEnum	✓	Python
Iterable	deque	✓	Python
Iterable	frozenset	✓	Python
Iterable	list	✓	Python
Iterable	set	✓	Python
Iterable	tuple	✓	Python
Iterable	Array	✓	JSON
NamedTuple	dict	✓	Python
NamedTuple	list	✓	Python
NamedTuple	namedtuple	✓	Python
NamedTuple	tuple	✓	Python
NamedTuple	Array	✓	JSON
NamedTuple	NamedTuple	✓	Python
None	None	✓	Python & JSON
Path	str	✓	JSON
Path	str		Python
Path	Path	✓	Python
Pattern	bytes	✓	Python	Input must be a valid pattern.
Pattern	str	✓	Python & JSON	Input must be a valid pattern.
Sequence	deque		Python
Sequence	list	✓	Python
Sequence	tuple		Python
Sequence	Array	✓	JSON
Type	Type	✓	Python
TypedDict	dict	✓	Python
TypedDict	Any	✓	Python
TypedDict	Mapping		Python	Must implement the mapping interface and have an items() method.
TypedDict	Object	✓	JSON
UUID	str	✓	JSON
UUID	str		Python
UUID	UUID	✓	Python

Field Type	Input	Strict	Input Source	Conditions
bool	bool	✓	Python & JSON
bool	float		Python & JSON	Allowed values: 0.0, 1.0.
bool	int		Python & JSON	Allowed values: 0, 1.
bool	str		Python & JSON	Allowed values: 'f', 'n', 'no', 'off', 'false', 'False', 't', 'y', 'on', 'yes', 'true', 'True'.
bytes	str	✓	JSON
callable	-		JSON	Never valid.
date	float		Python & JSON	Interpreted as seconds or ms from epoch. See speedate. Must be exact date.
date	int		Python & JSON	Interpreted as seconds or ms from epoch. See speedate. Must be exact date.
date	str		Python & JSON	Format: YYYY-MM-DD.
datetime	float		Python & JSON	Interpreted as seconds or ms from epoch, see speedate.
datetime	int		Python & JSON	Interpreted as seconds or ms from epoch, see speedate.
datetime	str		Python & JSON	Format: YYYY-MM-DDTHH:MM:SS.f. See speedate.
deque	Array	✓	JSON
dict	Object	✓	JSON
float	bool		Python & JSON
float	float	✓	Python & JSON	bool is explicitly forbidden.
float	int	✓	Python & JSON
float	str		Python & JSON	Must match [0-9]+(\.[0-9]+)?.
frozenset	Array	✓	JSON
int	bool		Python & JSON
int	float		Python & JSON	Must be exact int, e.g. val % 1 == 0, raises error for nan, inf.
int	int	✓	Python & JSON	bool is explicitly forbidden.
int	int		Python & JSON
int	str		Python & JSON	Must be numeric only, e.g. [0-9]+.
list	Array	✓	JSON
namedtuple	Array	✓	JSON
set	Array	✓	JSON
str	str	✓	Python & JSON
time	float		Python & JSON	Interpreted as seconds, range 0 - 86399.9*.
time	int		Python & JSON	Interpreted as seconds, range 0 - 86399.
time	str		Python & JSON	Format: HH:MM:SS.FFFFFF. See speedate.
timedelta	float		Python & JSON	Interpreted as seconds.
timedelta	int		Python & JSON	Interpreted as seconds.
timedelta	str		Python & JSON	Format: ISO8601. See speedate.
tuple	Array	✓	JSON
Any	Any	✓	Python & JSON
ByteSize	float	✓	Python & JSON
ByteSize	int	✓	Python & JSON
ByteSize	str	✓	Python & JSON
Decimal	float	✓	JSON
Decimal	float		Python & JSON
Decimal	int	✓	JSON
Decimal	int		Python & JSON
Decimal	str	✓	JSON
Decimal	str		Python & JSON	Must match [0-9]+(\.[0-9]+)?.
Enum	Any	✓	JSON	Input value must be convertible to enum values.
IPv4Address	str	✓	JSON
IPv4Address	str		Python & JSON
IPv4Interface	str	✓	JSON
IPv4Interface	str		Python & JSON
IPv4Network	str	✓	JSON
IPv4Network	str		Python & JSON
IPv6Address	str	✓	JSON
IPv6Address	str		Python & JSON
IPv6Interface	str	✓	JSON
IPv6Interface	str		Python & JSON
IPv6Network	str	✓	JSON
IPv6Network	str		Python & JSON
InstanceOf	-		JSON	Never valid.
IntEnum	Any	✓	JSON	Input value must be convertible to enum values.
Iterable	Array	✓	JSON
NamedTuple	Array	✓	JSON
None	None	✓	Python & JSON
Path	str	✓	JSON
Pattern	str	✓	Python & JSON	Input must be a valid pattern.
Sequence	Array	✓	JSON
TypedDict	Object	✓	JSON
UUID	str	✓	JSON

Field Type	Input	Strict	Input Source	Conditions
bool	bool	✓	Python & JSON
bytes	str	✓	JSON
deque	Array	✓	JSON
dict	Object	✓	JSON
float	float	✓	Python & JSON	bool is explicitly forbidden.
float	int	✓	Python & JSON
frozenset	Array	✓	JSON
int	int	✓	Python & JSON	bool is explicitly forbidden.
list	Array	✓	JSON
namedtuple	Array	✓	JSON
set	Array	✓	JSON
str	str	✓	Python & JSON
tuple	Array	✓	JSON
Any	Any	✓	Python & JSON
ByteSize	float	✓	Python & JSON
ByteSize	int	✓	Python & JSON
ByteSize	str	✓	Python & JSON
Decimal	float	✓	JSON
Decimal	int	✓	JSON
Decimal	str	✓	JSON
Enum	Any	✓	JSON	Input value must be convertible to enum values.
IPv4Address	str	✓	JSON
IPv4Interface	str	✓	JSON
IPv4Network	str	✓	JSON
IPv6Address	str	✓	JSON
IPv6Interface	str	✓	JSON
IPv6Network	str	✓	JSON
IntEnum	Any	✓	JSON	Input value must be convertible to enum values.
Iterable	Array	✓	JSON
NamedTuple	Array	✓	JSON
None	None	✓	Python & JSON
Path	str	✓	JSON
Pattern	str	✓	Python & JSON	Input must be a valid pattern.
Sequence	Array	✓	JSON
TypedDict	Object	✓	JSON
UUID	str	✓	JSON

Field Type	Input	Strict	Input Source	Conditions
bool	bool	✓	Python & JSON
bool	float		Python & JSON	Allowed values: 0.0, 1.0.
bool	int		Python & JSON	Allowed values: 0, 1.
bool	str		Python & JSON	Allowed values: 'f', 'n', 'no', 'off', 'false', 'False', 't', 'y', 'on', 'yes', 'true', 'True'.
bool	Decimal		Python	Allowed values: Decimal(0), Decimal(1).
bytes	bytearray		Python
bytes	bytes	✓	Python
bytes	str		Python
callable	Any	✓	Python	callable() check must return True.
date	bytes		Python	Format: YYYY-MM-DD (UTF-8).
date	date	✓	Python
date	datetime		Python	Must be exact date, eg. no H, M, S, f.
date	float		Python & JSON	Interpreted as seconds or ms from epoch. See speedate. Must be exact date.
date	int		Python & JSON	Interpreted as seconds or ms from epoch. See speedate. Must be exact date.
date	str		Python & JSON	Format: YYYY-MM-DD.
date	Decimal		Python	Interpreted as seconds or ms from epoch. See speedate. Must be exact date.
datetime	bytes		Python	Format: YYYY-MM-DDTHH:MM:SS.f. See speedate, (UTF-8).
datetime	date		Python
datetime	datetime	✓	Python
datetime	float		Python & JSON	Interpreted as seconds or ms from epoch, see speedate.
datetime	int		Python & JSON	Interpreted as seconds or ms from epoch, see speedate.
datetime	str		Python & JSON	Format: YYYY-MM-DDTHH:MM:SS.f. See speedate.
datetime	Decimal		Python	Interpreted as seconds or ms from epoch, see speedate.
deque	deque	✓	Python
deque	frozenset		Python
deque	list		Python
deque	set		Python
deque	tuple		Python
dict	dict	✓	Python
dict	Mapping		Python	Must implement the mapping interface and have an items() method.
float	bool		Python & JSON
float	bytes		Python	Must match [0-9]+(\.[0-9]+)?.
float	float	✓	Python & JSON	bool is explicitly forbidden.
float	int	✓	Python & JSON
float	str		Python & JSON	Must match [0-9]+(\.[0-9]+)?.
float	Decimal		Python
frozenset	deque		Python
frozenset	dict_keys		Python
frozenset	dict_values		Python
frozenset	frozenset	✓	Python
frozenset	list		Python
frozenset	set		Python
frozenset	tuple		Python
int	bool		Python & JSON
int	bytes		Python	Must be numeric only, e.g. [0-9]+.
int	float		Python & JSON	Must be exact int, e.g. val % 1 == 0, raises error for nan, inf.
int	int	✓	Python & JSON	bool is explicitly forbidden.
int	int		Python & JSON
int	str		Python & JSON	Must be numeric only, e.g. [0-9]+.
int	Decimal		Python	Must be exact int, e.g. val % 1 == 0.
list	deque		Python
list	dict_keys		Python
list	dict_values		Python
list	frozenset		Python
list	list	✓	Python
list	set		Python
list	tuple		Python
namedtuple	dict	✓	Python
namedtuple	list	✓	Python
namedtuple	namedtuple	✓	Python
namedtuple	tuple	✓	Python
namedtuple	NamedTuple	✓	Python
set	deque		Python
set	dict_keys		Python
set	dict_values		Python
set	frozenset		Python
set	list		Python
set	set	✓	Python
set	tuple		Python
str	bytearray		Python	Assumes UTF-8, error on unicode decoding error.
str	bytes		Python	Assumes UTF-8, error on unicode decoding error.
str	str	✓	Python & JSON
time	bytes		Python	Format: HH:MM:SS.FFFFFF. See speedate.
time	float		Python & JSON	Interpreted as seconds, range 0 - 86399.9*.
time	int		Python & JSON	Interpreted as seconds, range 0 - 86399.
time	str		Python & JSON	Format: HH:MM:SS.FFFFFF. See speedate.
time	time	✓	Python
time	Decimal		Python	Interpreted as seconds, range 0 - 86399.9*.
timedelta	bytes		Python	Format: ISO8601. See speedate, (UTF-8).
timedelta	float		Python & JSON	Interpreted as seconds.
timedelta	int		Python & JSON	Interpreted as seconds.
timedelta	str		Python & JSON	Format: ISO8601. See speedate.
timedelta	timedelta	✓	Python
timedelta	Decimal		Python	Interpreted as seconds.
tuple	deque		Python
tuple	dict_keys		Python
tuple	dict_values		Python
tuple	frozenset		Python
tuple	list		Python
tuple	set		Python
tuple	tuple	✓	Python
Any	Any	✓	Python & JSON
ByteSize	float	✓	Python & JSON
ByteSize	int	✓	Python & JSON
ByteSize	str	✓	Python & JSON
ByteSize	Decimal	✓	Python
Decimal	float		Python & JSON
Decimal	int		Python & JSON
Decimal	str		Python & JSON	Must match [0-9]+(\.[0-9]+)?.
Decimal	Decimal	✓	Python
Enum	Any		Python	Input value must be convertible to enum values.
Enum	Enum	✓	Python
IPv4Address	bytes		Python
IPv4Address	int		Python	integer representing the IP address, must be less than 2**32
IPv4Address	str		Python & JSON
IPv4Address	IPv4Address	✓	Python
IPv4Address	IPv4Interface	✓	Python
IPv4Interface	bytes		Python
IPv4Interface	int		Python	integer representing the IP address, must be less than 2**32
IPv4Interface	str		Python & JSON
IPv4Interface	tuple		Python
IPv4Interface	IPv4Address		Python
IPv4Interface	IPv4Interface	✓	Python
IPv4Network	bytes		Python
IPv4Network	int		Python	integer representing the IP network, must be less than 2**32
IPv4Network	str		Python & JSON
IPv4Network	IPv4Address		Python
IPv4Network	IPv4Interface		Python
IPv4Network	IPv4Network	✓	Python
IPv6Address	bytes		Python
IPv6Address	int		Python	integer representing the IP address, must be less than 2**128
IPv6Address	str		Python & JSON
IPv6Address	IPv6Address	✓	Python
IPv6Address	IPv6Interface	✓	Python
IPv6Interface	bytes		Python
IPv6Interface	int		Python	integer representing the IP address, must be less than 2**128
IPv6Interface	str		Python & JSON
IPv6Interface	tuple		Python
IPv6Interface	IPv6Address		Python
IPv6Interface	IPv6Interface	✓	Python
IPv6Network	bytes		Python
IPv6Network	int		Python	integer representing the IP address, must be less than 2**128
IPv6Network	str		Python & JSON
IPv6Network	IPv6Address		Python
IPv6Network	IPv6Interface		Python
IPv6Network	IPv6Network	✓	Python
InstanceOf	Any	✓	Python	isinstance() check must return True.
IntEnum	Any		Python	Input value must be convertible to enum values.
IntEnum	IntEnum	✓	Python
Iterable	deque	✓	Python
Iterable	frozenset	✓	Python
Iterable	list	✓	Python
Iterable	set	✓	Python
Iterable	tuple	✓	Python
NamedTuple	dict	✓	Python
NamedTuple	list	✓	Python
NamedTuple	namedtuple	✓	Python
NamedTuple	tuple	✓	Python
NamedTuple	NamedTuple	✓	Python
None	None	✓	Python & JSON
Path	str		Python
Path	Path	✓	Python
Pattern	bytes	✓	Python	Input must be a valid pattern.
Pattern	str	✓	Python & JSON	Input must be a valid pattern.
Sequence	deque		Python
Sequence	list	✓	Python
Sequence	tuple		Python
Type	Type	✓	Python
TypedDict	dict	✓	Python
TypedDict	Any	✓	Python
TypedDict	Mapping		Python	Must implement the mapping interface and have an items() method.
UUID	str		Python
UUID	UUID	✓	Python

Field Type	Input	Strict	Input Source	Conditions
bool	bool	✓	Python & JSON
bytes	bytes	✓	Python
callable	Any	✓	Python	callable() check must return True.
date	date	✓	Python
datetime	datetime	✓	Python
deque	deque	✓	Python
dict	dict	✓	Python
float	float	✓	Python & JSON	bool is explicitly forbidden.
float	int	✓	Python & JSON
frozenset	frozenset	✓	Python
int	int	✓	Python & JSON	bool is explicitly forbidden.
list	list	✓	Python
namedtuple	dict	✓	Python
namedtuple	list	✓	Python
namedtuple	namedtuple	✓	Python
namedtuple	tuple	✓	Python
namedtuple	NamedTuple	✓	Python
set	set	✓	Python
str	str	✓	Python & JSON
time	time	✓	Python
timedelta	timedelta	✓	Python
tuple	tuple	✓	Python
Any	Any	✓	Python & JSON
ByteSize	float	✓	Python & JSON
ByteSize	int	✓	Python & JSON
ByteSize	str	✓	Python & JSON
ByteSize	Decimal	✓	Python
Decimal	Decimal	✓	Python
Enum	Enum	✓	Python
IPv4Address	IPv4Address	✓	Python
IPv4Address	IPv4Interface	✓	Python
IPv4Interface	IPv4Interface	✓	Python
IPv4Network	IPv4Network	✓	Python
IPv6Address	IPv6Address	✓	Python
IPv6Address	IPv6Interface	✓	Python
IPv6Interface	IPv6Interface	✓	Python
IPv6Network	IPv6Network	✓	Python
InstanceOf	Any	✓	Python	isinstance() check must return True.
IntEnum	IntEnum	✓	Python
Iterable	deque	✓	Python
Iterable	frozenset	✓	Python
Iterable	list	✓	Python
Iterable	set	✓	Python
Iterable	tuple	✓	Python
NamedTuple	dict	✓	Python
NamedTuple	list	✓	Python
NamedTuple	namedtuple	✓	Python
NamedTuple	tuple	✓	Python
NamedTuple	NamedTuple	✓	Python
None	None	✓	Python & JSON
Path	Path	✓	Python
Pattern	bytes	✓	Python	Input must be a valid pattern.
Pattern	str	✓	Python & JSON	Input must be a valid pattern.
Sequence	list	✓	Python
Type	Type	✓	Python
TypedDict	dict	✓	Python
TypedDict	Any	✓	Python
UUID	UUID	✓	Python