Pydantic Validation

Data validation using Python type hints.

Fast and extensible, Pydantic plays nicely with your linters/IDE/brain. Define how data should be in pure, canonical Python 3.9+; validate it with Pydantic.

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Pydantic V1.10 vs. V2

Pydantic V2 is a ground-up rewrite that offers many new features, performance improvements, and some breaking changes compared to Pydantic V1.

If you're using Pydantic V1 you may want to look at the pydantic V1.10 Documentation or, 1.10.X-fixes git branch. Pydantic V2 also ships with the latest version of Pydantic V1 built in so that you can incrementally upgrade your code base and projects: from pydantic import v1 as pydantic_v1.

Help

See documentation for more details.

Installation

Install using pip install -U pydantic or conda install pydantic -c conda-forge. For more installation options to make Pydantic even faster, see the Install section in the documentation.

A Simple Example

from datetime import datetime
from typing import Optional
from pydantic import BaseModel

class User(BaseModel):
    id: int
    name: str = 'John Doe'
    signup_ts: Optional[datetime] = None
    friends: list[int] = []

external_data = {'id': '123', 'signup_ts': '2017-06-01 12:22', 'friends': [1, '2', b'3']}
user = User(**external_data)
print(user)
#> User id=123 name='John Doe' signup_ts=datetime.datetime(2017, 6, 1, 12, 22) friends=[1, 2, 3]
print(user.id)
#> 123

Contributing

For guidance on setting up a development environment and how to make a contribution to Pydantic, see Contributing to Pydantic.

Reporting a Security Vulnerability

See our security policy.

Changelog

v2.12.3 (2025-10-17)

GitHub release

What's Changed

This is the third 2.13 patch release, fixing issues related to the FieldInfo class, and reverting a change to the supported after model validator function signatures.

• Raise a warning when an invalid after model validator function signature is raised by @Viicos in #12414. Starting in 2.12.0, using class methods for after model validators raised an error, but the error wasn't raised concistently. We decided to emit a deprecation warning instead.
• Add FieldInfo.asdict() method, improve documentation around FieldInfo by @Viicos in #12411. This also add back support for mutations on FieldInfo classes, that are reused as Annotated metadata. However, note that this is still not a supported pattern. Instead, please refer to the added example in the documentation.

The blog post section on changes was also updated to document the changes related to serialize_as_any.

Fixes

• Release a new pydantic-core version, as a corrupted CPython 3.10 manylinux2014_aarch64 wheel got uploaded (pydantic-core#1843).
• Fix issue with recursive generic models with a parent model class by @Viicos in #12398

v2.12.2 (2025-10-14)

GitHub release

What's Changed

Fixes

• Release a new pydantic-core version, as a corrupted CPython 3.10 manylinux2014_aarch64 wheel got uploaded (pydantic-core#1843).
• Fix issue with recursive generic models with a parent model class by @Viicos in #12398

v2.12.1 (2025-10-13)

GitHub release

What's Changed

This is the first 2.12 patch release, addressing most (but not all yet) regressions from the initial 2.12.0 release.

Fixes

• Do not evaluate annotations when inspecting validators and serializers by @Viicos in #12355
• Make sure None is converted as NoneType in Python 3.14 by @Viicos in #12370
• Backport V1 runtime warning when using Python 3.14 by @Viicos in #12367
• Fix error message for invalid validator signatures by @Viicos in #12366
• Populate field name in ValidationInfo for validation of default value by @Viicos in pydantic-core#1826
• Encode credentials in MultiHostUrl builder by @willswire in pydantic-core#1829
• Respect field serializers when using serialize_as_any serialization flag by @davidhewitt in pydantic-core#1829
• Fix various RootModel serialization issues by @davidhewitt in pydantic-core#1836

New Contributors

• @willswire made their first contribution in pydantic-core#1829

v2.12.0 (2025-10-07)

GitHub release

What's Changed

This is the final 2.12 release. It features the work of 20 external contributors and provides useful new features, along with initial Python 3.14 support. Several minor changes (considered non-breaking changes according to our versioning policy) are also included in this release. Make sure to look into them before upgrading.

Note that Pydantic V1 is not compatible with Python 3.14 and greater.

Changes (see the alpha and beta releases for additional changes since 2.11):

Packaging

• Update V1 copy to v1.10.24 by @Viicos in #12338

New Features

• Add extra parameter to the validate functions by @anvilpete in #12233
• Add exclude_computed_fields serialization option by @Viicos in #12334
• Add preverse_empty_path URL options by @Viicos in #12336
• Add union_format parameter to JSON Schema generation by @Viicos in #12147
• Add __qualname__ parameter for create_model by @Atry in #12001

Fixes

• Do not try to infer name from lambda definitions in pipelines API by @Viicos in #12289
• Use proper namespace for functions in TypeAdapter by @Viicos in #12324
• Use Any for context type annotation in TypeAdapter by @inducer in #12279
• Expose FieldInfo in pydantic.fields.__all__ by @Viicos in #12339
• Respect validation_alias in @validate_call by @Viicos in #12340
• Use Any as context annotation in plugin API by @Viicos in #12341
• Use proper stacklevel in warnings when possible by @Viicos in #12342

New Contributors

• @anvilpete made their first contribution in #12233
• @JonathanWindell made their first contribution in #12327
• @inducer made their first contribution in #12279
• @Atry made their first contribution in #12001

v2.12.0b1 (2025-10-03)

GitHub release

This is the first beta release of the upcoming 2.12 release.

What's Changed

Packaging

• Bump pydantic-core to v2.40.1 by @Viicos in #12314

New Features

• Add support for exclude_if at the field level by @andresliszt in #12141
• Add ValidateAs annotation helper by @Viicos in #11942
• Add configuration options for validation and JSON serialization of temporal types by @ollz272 in #12068
• Add support for PEP 728 by @Viicos in #12179
• Add field name in serialization error by @NicolasPllr1 in pydantic-core#1799
• Add option to preserve empty URL paths by @davidhewitt in pydantic-core#1789

Changes

• Raise error if an incompatible pydantic-core version is installed by @Viicos in #12196
• Remove runtime warning for experimental features by @Viicos in #12265
• Warn if registering virtual subclasses on Pydantic models by @Viicos in #11669

Fixes

• Fix __getattr__() behavior on Pydantic models when a property raised an AttributeError and extra values are present by @raspuchin in #12106
• Add test to prevent regression with Pydantic models used as annotated metadata by @Viicos in #12133
• Allow to use property setters on Pydantic dataclasses with validate_assignment set by @Viicos in #12173
• Fix mypy v2 plugin for upcoming mypy release by @cdce8p in #12209
• Respect custom title in functions JSON Schema by @Viicos in #11892
• Fix ImportString JSON serialization for objects with a name attribute by @chr1sj0nes in #12219
• Do not error on fields overridden by methods in the mypy plugin by @Viicos in #12290

New Contributors

• @raspuchin made their first contribution in #12106
• @chr1sj0nes made their first contribution in #12219

v2.12.0a1 (2025-07-26)

GitHub release

This is the first alpha release of the upcoming 2.12 release, which adds initial support for Python 3.14.

What's Changed

New Features

• Add __pydantic_on_complete__() hook that is called once model is fully ready to be used by @DouweM in #11762
• Add initial support for Python 3.14 by @Viicos in #11991
• Add regex patterns to JSON schema for Decimal type by @Dima-Bulavenko in #11987
• Add support for doc attribute on dataclass fields by @Viicos in #12077
• Add experimental MISSING sentinel by @Viicos in #11883

Changes

• Allow config and bases to be specified together in create_model() by @Viicos in #11714
• Move some field logic out of the GenerateSchema class by @Viicos in #11733
• Always make use of inspect.getsourcelines() for docstring extraction on Python 3.13 and greater by @Viicos in #11829
• Only support the latest Mypy version by @Viicos in #11832
• Do not implicitly convert after model validators to class methods by @Viicos in #11957
• Refactor FieldInfo creation implementation by @Viicos in #11898
• Make Secret covariant by @bluenote10 in #12008
• Emit warning when field-specific metadata is used in invalid contexts by @Viicos in #12028

Fixes

• Properly fetch plain serializer function when serializing default value in JSON Schema by @Viicos in #11721
• Remove generics cache workaround by @Viicos in #11755
• Remove coercion of decimal constraints by @Viicos in #11772
• Fix crash when expanding root type in the mypy plugin by @Viicos in #11735
• Only mark model as complete once all fields are complete by @DouweM in #11759
• Do not provide field_name in validator core schemas by @DouweM in #11761
• Fix issue with recursive generic models by @Viicos in #11775
• Fix qualified name comparison of private attributes during namespace inspection by @karta9821 in #11803
• Make sure Pydantic dataclasses with slots and validate_assignment can be unpickled by @Viicos in #11769
• Traverse function-before schemas during schema gathering by @Viicos in #11801
• Fix check for stdlib dataclasses by @Viicos in #11822
• Check if FieldInfo is complete after applying type variable map by @Viicos in #11855
• Do not delete mock validator/serializer in model_rebuild() by @Viicos in #11890
• Rebuild dataclass fields before schema generation by @Viicos in #11949
• Always store the original field assignment on FieldInfo by @Viicos in #11946
• Do not use deprecated methods as default field values by @Viicos in #11914
• Allow callable discriminator to be applied on PEP 695 type aliases by @Viicos in #11941
• Suppress core schema generation warning when using SkipValidation by @ygsh0816 in #12002
• Do not emit typechecking error for invalid Field() default with validate_default set to True by @Viicos in #11988
• Refactor logic to support Pydantic's Field() function in dataclasses by @Viicos in #12051

Packaging

• Update project metadata to use PEP 639 by @Viicos in #11694
• Bump mkdocs-llmstxt to v0.2.0 by @Viicos in #11725
• Bump pydantic-core to v2.35.1 by @Viicos in #11963
• Bump dawidd6/action-download-artifact from 10 to 11 by @dependabot[bot] in #12033
• Bump astral-sh/setup-uv from 5 to 6 by @dependabot[bot] in #11826
• Update mypy to 1.17.0 by @Viicos in #12076

New Contributors

• @parth-paradkar made their first contribution in #11695
• @dqkqd made their first contribution in #11739
• @fhightower made their first contribution in #11722
• @gbaian10 made their first contribution in #11766
• @DouweM made their first contribution in #11759
• @bowenliang123 made their first contribution in #11719
• @rawwar made their first contribution in #11799
• @karta9821 made their first contribution in #11803
• @jinnovation made their first contribution in #11834
• @zmievsa made their first contribution in #11861
• @Otto-AA made their first contribution in #11860
• @ygsh0816 made their first contribution in #12002
• @lukland made their first contribution in #12015
• @Dima-Bulavenko made their first contribution in #11987
• @GSemikozov made their first contribution in #12050
• @hannah-heywa made their first contribution in #12082

v2.11.7 (2025-06-14)

GitHub release

What's Changed

Fixes

• Copy FieldInfo instance if necessary during FieldInfo build by @Viicos in #11898

v2.11.6 (2025-06-13)

GitHub release

What's Changed

Fixes

• Rebuild dataclass fields before schema generation by @Viicos in #11949
• Always store the original field assignment on FieldInfo by @Viicos in #11946

v2.11.5 (2025-05-22)

GitHub release

What's Changed

Fixes

• Check if FieldInfo is complete after applying type variable map by @Viicos in #11855
• Do not delete mock validator/serializer in model_rebuild() by @Viicos in #11890
• Do not duplicate metadata on model rebuild by @Viicos in #11902

v2.11.4 (2025-04-29)

GitHub release

What's Changed

Packaging

• Bump mkdocs-llmstxt to v0.2.0 by @Viicos in #11725

Changes

• Allow config and bases to be specified together in create_model() by @Viicos in #11714. This change was backported as it was previously possible (although not meant to be supported) to provide model_config as a field, which would make it possible to provide both configuration and bases.

Fixes

• Remove generics cache workaround by @Viicos in #11755
• Remove coercion of decimal constraints by @Viicos in #11772
• Fix crash when expanding root type in the mypy plugin by @Viicos in #11735
• Fix issue with recursive generic models by @Viicos in #11775
• Traverse function-before schemas during schema gathering by @Viicos in #11801

v2.11.3 (2025-04-08)

GitHub release

What's Changed

Packaging

• Update V1 copy to v1.10.21 by @Viicos in #11706

Fixes

• Preserve field description when rebuilding model fields by @Viicos in #11698

v2.11.2 (2025-04-03)

GitHub release

What's Changed

Fixes

• Bump pydantic-core to v2.33.1 by @Viicos in #11678
• Make sure __pydantic_private__ exists before setting private attributes by @Viicos in #11666
• Do not override FieldInfo._complete when using field from parent class by @Viicos in #11668
• Provide the available definitions when applying discriminated unions by @Viicos in #11670
• Do not expand root type in the mypy plugin for variables by @Viicos in #11676
• Mention the attribute name in model fields deprecation message by @Viicos in #11674
• Properly validate parameterized mappings by @Viicos in #11658

v2.11.1 (2025-03-28)

GitHub release

What's Changed

Fixes

• Do not override 'definitions-ref' schemas containing serialization schemas or metadata by @Viicos in #11644

v2.11.0 (2025-03-27)

GitHub release

What's Changed

Pydantic v2.11 is a version strongly focused on build time performance of Pydantic models (and core schema generation in general). See the blog post for more details.

Packaging

• Bump pydantic-core to v2.33.0 by @Viicos in #11631

New Features

• Add encoded_string() method to the URL types by @YassinNouh21 in #11580
• Add support for defer_build with @validate_call decorator by @Viicos in #11584
• Allow @with_config decorator to be used with keyword arguments by @Viicos in #11608
• Simplify customization of default value inclusion in JSON Schema generation by @Viicos in #11634
• Add generate_arguments_schema() function by @Viicos in #11572

Fixes

• Allow generic typed dictionaries to be used for unpacked variadic keyword parameters by @Viicos in #11571
• Fix runtime error when computing model string representation involving cached properties and self-referenced models by @Viicos in #11579
• Preserve other steps when using the ellipsis in the pipeline API by @Viicos in #11626
• Fix deferred discriminator application logic by @Viicos in #11591

New Contributors

• @cmenon12 made their first contribution in #11562
• @Jeukoh made their first contribution in #11611

v2.11.0b2 (2025-03-17)

GitHub release

What's Changed

Packaging

• Bump pydantic-core to v2.32.0 by @Viicos in #11567

New Features

• Add experimental support for free threading by @Viicos in #11516

Fixes

• Fix NotRequired qualifier not taken into account in stringified annotation by @Viicos in #11559

New Contributors

• @joren485 made their first contribution in #11547

v2.11.0b1 (2025-03-06)

GitHub release

What's Changed

Packaging

• Add a check_pydantic_core_version() function by @Viicos in https://github.com/pydantic/pydantic/pull/11324
• Remove greenlet development dependency by @Viicos in https://github.com/pydantic/pydantic/pull/11351
• Use the typing-inspection library by @Viicos in https://github.com/pydantic/pydantic/pull/11479
• Bump pydantic-core to v2.31.1 by @sydney-runkle in https://github.com/pydantic/pydantic/pull/11526

New Features

• Support unsubstituted type variables with both a default and a bound or constraints by @FyZzyss in https://github.com/pydantic/pydantic/pull/10789
• Add a default_factory_takes_validated_data property to FieldInfo by @Viicos in https://github.com/pydantic/pydantic/pull/11034
• Raise a better error when a generic alias is used inside type[] by @Viicos in https://github.com/pydantic/pydantic/pull/11088
• Properly support PEP 695 generics syntax by @Viicos in https://github.com/pydantic/pydantic/pull/11189
• Properly support type variable defaults by @Viicos in https://github.com/pydantic/pydantic/pull/11332
• Add support for validating v6, v7, v8 UUIDs by @astei in https://github.com/pydantic/pydantic/pull/11436
• Improve alias configuration APIs by @sydney-runkle in https://github.com/pydantic/pydantic/pull/11468

Changes

• Rework create_model field definitions format by @Viicos in https://github.com/pydantic/pydantic/pull/11032
• Raise a deprecation warning when a field is annotated as final with a default value by @Viicos in https://github.com/pydantic/pydantic/pull/11168
• Deprecate accessing model_fields and model_computed_fields on instances by @Viicos in https://github.com/pydantic/pydantic/pull/11169
• Breaking Change: Move core schema generation logic for path types inside the GenerateSchema class by @sydney-runkle in https://github.com/pydantic/pydantic/pull/10846
• Remove Python 3.8 Support by @sydney-runkle in https://github.com/pydantic/pydantic/pull/11258
• Optimize calls to get_type_ref by @Viicos in https://github.com/pydantic/pydantic/pull/10863
• Disable pydantic-core core schema validation by @sydney-runkle in https://github.com/pydantic/pydantic/pull/11271

Performance

• Only evaluate FieldInfo annotations if required during schema building by @Viicos in https://github.com/pydantic/pydantic/pull/10769
• Improve __setattr__ performance of Pydantic models by caching setter functions by @MarkusSintonen in https://github.com/pydantic/pydantic/pull/10868
• Improve annotation application performance by @Viicos in https://github.com/pydantic/pydantic/pull/11186
• Improve performance of _typing_extra module by @Viicos in https://github.com/pydantic/pydantic/pull/11255
• Refactor and optimize schema cleaning logic by @Viicos in https://github.com/pydantic/pydantic/pull/11244
• Create a single dictionary when creating a CoreConfig instance by @sydney-runkle in https://github.com/pydantic/pydantic/pull/11384
• Bump pydantic-core and thus use SchemaValidator and SchemaSerializer caching by @sydney-runkle in https://github.com/pydantic/pydantic/pull/11402
• Reuse cached core schemas for parametrized generic Pydantic models by @MarkusSintonen in https://github.com/pydantic/pydantic/pull/11434

Fixes

• Improve TypeAdapter instance repr by @sydney-runkle in https://github.com/pydantic/pydantic/pull/10872
• Use the correct frame when instantiating a parametrized TypeAdapter by @Viicos in https://github.com/pydantic/pydantic/pull/10893
• Infer final fields with a default value as class variables in the mypy plugin by @Viicos in https://github.com/pydantic/pydantic/pull/11121
• Recursively unpack Literal values if using PEP 695 type aliases by @Viicos in https://github.com/pydantic/pydantic/pull/11114
• Override __subclasscheck__ on ModelMetaclass to avoid memory leak and performance issues by @Viicos in https://github.com/pydantic/pydantic/pull/11116
• Remove unused _extract_get_pydantic_json_schema() parameter by @Viicos in https://github.com/pydantic/pydantic/pull/11155
• Improve discriminated union error message for invalid union variants by @Viicos in https://github.com/pydantic/pydantic/pull/11161
• Unpack PEP 695 type aliases if using the Annotated form by @Viicos in https://github.com/pydantic/pydantic/pull/11109
• Add missing stacklevel in deprecated_instance_property warning by @Viicos in https://github.com/pydantic/pydantic/pull/11200
• Copy WithJsonSchema schema to avoid sharing mutated data by @thejcannon in https://github.com/pydantic/pydantic/pull/11014
• Do not cache parametrized models when in the process of parametrizing another model by @Viicos in https://github.com/pydantic/pydantic/pull/10704
• Add discriminated union related metadata entries to the CoreMetadata definition by @Viicos in https://github.com/pydantic/pydantic/pull/11216
• Consolidate schema definitions logic in the _Definitions class by @Viicos in https://github.com/pydantic/pydantic/pull/11208
• Support initializing root model fields with values of the root type in the mypy plugin by @Viicos in https://github.com/pydantic/pydantic/pull/11212
• Fix various issues with dataclasses and use_attribute_docstrings by @Viicos in https://github.com/pydantic/pydantic/pull/11246
• Only compute normalized decimal places if necessary in decimal_places_validator by @misrasaurabh1 in https://github.com/pydantic/pydantic/pull/11281
• Add support for validation_alias in the mypy plugin by @Viicos in https://github.com/pydantic/pydantic/pull/11295
• Fix JSON Schema reference collection with "examples" keys by @Viicos in https://github.com/pydantic/pydantic/pull/11305
• Do not transform model serializer functions as class methods in the mypy plugin by @Viicos in https://github.com/pydantic/pydantic/pull/11298
• Simplify GenerateJsonSchema.literal_schema() implementation by @misrasaurabh1 in https://github.com/pydantic/pydantic/pull/11321
• Add additional allowed schemes for ClickHouseDsn by @Maze21127 in https://github.com/pydantic/pydantic/pull/11319
• Coerce decimal constraints to Decimal instances by @Viicos in https://github.com/pydantic/pydantic/pull/11350
• Use the correct JSON Schema mode when handling function schemas by @Viicos in https://github.com/pydantic/pydantic/pull/11367
• Improve exception message when encountering recursion errors during type evaluation by @Viicos in https://github.com/pydantic/pydantic/pull/11356
• Always include additionalProperties: True for arbitrary dictionary schemas by @austinyu in https://github.com/pydantic/pydantic/pull/11392
• Expose fallback parameter in serialization methods by @Viicos in https://github.com/pydantic/pydantic/pull/11398
• Fix path serialization behavior by @sydney-runkle in https://github.com/pydantic/pydantic/pull/11416
• Do not reuse validators and serializers during model rebuild by @Viicos in https://github.com/pydantic/pydantic/pull/11429
• Collect model fields when rebuilding a model by @Viicos in https://github.com/pydantic/pydantic/pull/11388
• Allow cached properties to be altered on frozen models by @Viicos in https://github.com/pydantic/pydantic/pull/11432
• Fix tuple serialization for Sequence types by @sydney-runkle in https://github.com/pydantic/pydantic/pull/11435
• Fix: do not check for __get_validators__ on classes where __get_pydantic_core_schema__ is also defined by @tlambert03 in https://github.com/pydantic/pydantic/pull/11444
• Allow callable instances to be used as serializers by @Viicos in https://github.com/pydantic/pydantic/pull/11451
• Improve error thrown when overriding field with a property by @sydney-runkle in https://github.com/pydantic/pydantic/pull/11459
• Fix JSON Schema generation with referenceable core schemas holding JSON metadata by @Viicos in https://github.com/pydantic/pydantic/pull/11475
• Support strict specification on union member types by @sydney-runkle in https://github.com/pydantic/pydantic/pull/11481
• Implicitly set validate_by_name to True when validate_by_alias is False by @sydney-runkle in https://github.com/pydantic/pydantic/pull/11503
• Change type of Any when synthesizing BaseSettings.__init__ signature in the mypy plugin by @Viicos in https://github.com/pydantic/pydantic/pull/11497
• Support type variable defaults referencing other type variables by @Viicos in https://github.com/pydantic/pydantic/pull/11520
• Fix ValueError on year zero by @davidhewitt in https://github.com/pydantic/pydantic-core/pull/1583
• dataclass InitVar shouldn't be required on serialization by @sydney-runkle in https://github.com/pydantic/pydantic-core/pull/1602

New Contributors

• @FyZzyss made their first contribution in https://github.com/pydantic/pydantic/pull/10789
• @tamird made their first contribution in https://github.com/pydantic/pydantic/pull/10948
• @felixxm made their first contribution in https://github.com/pydantic/pydantic/pull/11077
• @alexprabhat99 made their first contribution in https://github.com/pydantic/pydantic/pull/11082
• @Kharianne made their first contribution in https://github.com/pydantic/pydantic/pull/11111
• @mdaffad made their first contribution in https://github.com/pydantic/pydantic/pull/11177
• @thejcannon made their first contribution in https://github.com/pydantic/pydantic/pull/11014
• @thomasfrimannkoren made their first contribution in https://github.com/pydantic/pydantic/pull/11251
• @usernameMAI made their first contribution in https://github.com/pydantic/pydantic/pull/11275
• @ananiavito made their first contribution in https://github.com/pydantic/pydantic/pull/11302
• @pawamoy made their first contribution in https://github.com/pydantic/pydantic/pull/11311
• @Maze21127 made their first contribution in https://github.com/pydantic/pydantic/pull/11319
• @kauabh made their first contribution in https://github.com/pydantic/pydantic/pull/11369
• @jaceklaskowski made their first contribution in https://github.com/pydantic/pydantic/pull/11353
• @tmpbeing made their first contribution in https://github.com/pydantic/pydantic/pull/11375
• @petyosi made their first contribution in https://github.com/pydantic/pydantic/pull/11405
• @austinyu made their first contribution in https://github.com/pydantic/pydantic/pull/11392
• @mikeedjones made their first contribution in https://github.com/pydantic/pydantic/pull/11402
• @astei made their first contribution in https://github.com/pydantic/pydantic/pull/11436
• @dsayling made their first contribution in https://github.com/pydantic/pydantic/pull/11522
• @sobolevn made their first contribution in https://github.com/pydantic/pydantic-core/pull/1645

v2.11.0a2 (2025-02-10)

GitHub release

What's Changed

Pydantic v2.11 is a version strongly focused on build time performance of Pydantic models (and core schema generation in general). This is another early alpha release, meant to collect early feedback from users having issues with core schema builds.

Packaging

• Bump ruff from 0.9.2 to 0.9.5 by @Viicos in #11407
• Bump pydantic-core to v2.29.0 by @mikeedjones in #11402
• Use locally-built rust with symbols & pgo by @davidhewitt in #11403

Performance

• Create a single dictionary when creating a CoreConfig instance by @sydney-runkle in #11384

Fixes

• Use the correct JSON Schema mode when handling function schemas by @Viicos in #11367
• Fix JSON Schema reference logic with examples keys by @Viicos in #11366
• Improve exception message when encountering recursion errors during type evaluation by @Viicos in #11356
• Always include additionalProperties: True for arbitrary dictionary schemas by @austinyu in #11392
• Expose fallback parameter in serialization methods by @Viicos in #11398
• Fix path serialization behavior by @sydney-runkle in #11416

New Contributors

• @kauabh made their first contribution in #11369
• @jaceklaskowski made their first contribution in #11353
• @tmpbeing made their first contribution in #11375
• @petyosi made their first contribution in #11405
• @austinyu made their first contribution in #11392
• @mikeedjones made their first contribution in #11402

v2.11.0a1 (2025-01-30)

GitHub release

What's Changed

Pydantic v2.11 is a version strongly focused on build time performance of Pydantic models (and core schema generation in general). This is an early alpha release, meant to collect early feedback from users having issues with core schema builds.

Packaging

• Bump dawidd6/action-download-artifact from 6 to 7 by @dependabot in #11018
• Re-enable memray related tests on Python 3.12+ by @Viicos in #11191
• Bump astral-sh/setup-uv to 5 by @dependabot in #11205
• Bump ruff to v0.9.0 by @sydney-runkle in #11254
• Regular uv.lock deps update by @sydney-runkle in #11333
• Add a check_pydantic_core_version() function by @Viicos in #11324
• Remove greenlet development dependency by @Viicos in #11351
• Bump pydantic-core to v2.28.0 by @Viicos in #11364

New Features

• Support unsubstituted type variables with both a default and a bound or constraints by @FyZzyss in #10789
• Add a default_factory_takes_validated_data property to FieldInfo by @Viicos in #11034
• Raise a better error when a generic alias is used inside type[] by @Viicos in #11088
• Properly support PEP 695 generics syntax by @Viicos in #11189
• Properly support type variable defaults by @Viicos in #11332

Changes

• Rework create_model field definitions format by @Viicos in #11032
• Raise a deprecation warning when a field is annotated as final with a default value by @Viicos in #11168
• Deprecate accessing model_fields and model_computed_fields on instances by @Viicos in #11169
• Move core schema generation logic for path types inside the GenerateSchema class by @sydney-runkle in #10846
• Move deque schema gen to GenerateSchema class by @sydney-runkle in #11239
• Move Mapping schema gen to GenerateSchema to complete removal of prepare_annotations_for_known_type workaround by @sydney-runkle in #11247
• Remove Python 3.8 Support by @sydney-runkle in #11258
• Disable pydantic-core core schema validation by @sydney-runkle in #11271

Performance

• Only evaluate FieldInfo annotations if required during schema building by @Viicos in #10769
• Optimize calls to get_type_ref by @Viicos in #10863
• Improve __setattr__ performance of Pydantic models by caching setter functions by @MarkusSintonen in #10868
• Improve annotation application performance by @Viicos in #11186
• Improve performance of _typing_extra module by @Viicos in #11255
• Refactor and optimize schema cleaning logic by @Viicos and @MarkusSintonen in #11244

Fixes

• Add validation tests for _internal/_validators.py by @tkasuz in #10763
• Improve TypeAdapter instance repr by @sydney-runkle in #10872
• Revert "ci: use locally built pydantic-core with debug symbols by @sydney-runkle in #10942
• Re-enable all FastAPI tests by @tamird in #10948
• Fix typo in HISTORY.md. by @felixxm in #11077
• Infer final fields with a default value as class variables in the mypy plugin by @Viicos in #11121
• Recursively unpack Literal values if using PEP 695 type aliases by @Viicos in #11114
• Override __subclasscheck__ on ModelMetaclass to avoid memory leak and performance issues by @Viicos in #11116
• Remove unused _extract_get_pydantic_json_schema() parameter by @Viicos in #11155
• Add FastAPI and SQLModel to third-party tests by @sydney-runkle in #11044
• Fix conditional expressions syntax for third-party tests by @Viicos in #11162
• Move FastAPI tests to third-party workflow by @Viicos in #11164
• Improve discriminated union error message for invalid union variants by @Viicos in #11161
• Unpack PEP 695 type aliases if using the Annotated form by @Viicos in #11109
• Include openapi-python-client check in issue creation for third-party failures, use main branch by @sydney-runkle in #11182
• Add pandera third-party tests by @Viicos in #11193
• Add ODMantic third-party tests by @sydney-runkle in #11197
• Add missing stacklevel in deprecated_instance_property warning by @Viicos in #11200
• Copy WithJsonSchema schema to avoid sharing mutated data by @thejcannon in #11014
• Do not cache parametrized models when in the process of parametrizing another model by @Viicos in #10704
• Re-enable Beanie third-party tests by @Viicos in #11214
• Add discriminated union related metadata entries to the CoreMetadata definition by @Viicos in #11216
• Consolidate schema definitions logic in the _Definitions class by @Viicos in #11208
• Support initializing root model fields with values of the root type in the mypy plugin by @Viicos in #11212
• Fix various issues with dataclasses and use_attribute_docstrings by @Viicos in #11246
• Only compute normalized decimal places if necessary in decimal_places_validator by @misrasaurabh1 in #11281
• Fix two misplaced sentences in validation errors documentation by @ananiavito in #11302
• Fix mkdocstrings inventory example in documentation by @pawamoy in #11311
• Add support for validation_alias in the mypy plugin by @Viicos in #11295
• Do not transform model serializer functions as class methods in the mypy plugin by @Viicos in #11298
• Simplify GenerateJsonSchema.literal_schema() implementation by @misrasaurabh1 in #11321
• Add additional allowed schemes for ClickHouseDsn by @Maze21127 in #11319
• Coerce decimal constraints to Decimal instances by @Viicos in #11350
• Fix ValueError on year zero by @davidhewitt in pydantic-core#1583

New Contributors

• @FyZzyss made their first contribution in #10789
• @tamird made their first contribution in #10948
• @felixxm made their first contribution in #11077
• @alexprabhat99 made their first contribution in #11082
• @Kharianne made their first contribution in #11111
• @mdaffad made their first contribution in #11177
• @thejcannon made their first contribution in #11014
• @thomasfrimannkoren made their first contribution in #11251
• @usernameMAI made their first contribution in #11275
• @ananiavito made their first contribution in #11302
• @pawamoy made their first contribution in #11311
• @Maze21127 made their first contribution in #11319

v2.10.6 (2025-01-23)

GitHub release

What's Changed

Fixes

• Fix JSON Schema reference collection with 'examples' keys by @Viicos in #11325
• Fix url python serialization by @sydney-runkle in #11331

v2.10.5 (2025-01-08)

GitHub release

What's Changed

Fixes

• Remove custom MRO implementation of Pydantic models by @Viicos in #11184
• Fix URL serialization for unions by @sydney-runkle in #11233

v2.10.4 (2024-12-18)

GitHub release

What's Changed

Packaging

• Bump pydantic-core to v2.27.2 by @davidhewitt in #11138

Fixes

• Fix for comparison of AnyUrl objects by @alexprabhat99 in #11082
• Properly fetch PEP 695 type params for functions, do not fetch annotations from signature by @Viicos in #11093
• Include JSON Schema input core schema in function schemas by @Viicos in #11085
• Add len to _BaseUrl to avoid TypeError by @Kharianne in #11111
• Make sure the type reference is removed from the seen references by @Viicos in #11143

New Contributors

• @FyZzyss made their first contribution in #10789
• @tamird made their first contribution in #10948
• @felixxm made their first contribution in #11077
• @alexprabhat99 made their first contribution in #11082
• @Kharianne made their first contribution in #11111

v2.10.3 (2024-12-03)

GitHub release

What's Changed

Fixes

• Set fields when defer_build is set on Pydantic dataclasses by @Viicos in #10984
• Do not resolve the JSON Schema reference for dict core schema keys by @Viicos in #10989
• Use the globals of the function when evaluating the return type for PlainSerializer and WrapSerializer functions by @Viicos in #11008
• Fix host required enforcement for urls to be compatible with v2.9 behavior by @sydney-runkle in #11027
• Add a default_factory_takes_validated_data property to FieldInfo by @Viicos in #11034
• Fix url json schema in serialization mode by @sydney-runkle in #11035

v2.10.2 (2024-11-25)

GitHub release

What's Changed

Fixes

• Only evaluate FieldInfo annotations if required during schema building by @Viicos in #10769
• Do not evaluate annotations for private fields by @Viicos in #10962
• Support serialization as any for Secret types and Url types by @sydney-runkle in #10947
• Fix type hint of Field.default to be compatible with Python 3.8 and 3.9 by @Viicos in #10972
• Add hashing support for URL types by @sydney-runkle in #10975
• Hide BaseModel.__replace__ definition from type checkers by @Viicos in #10979

v2.10.1 (2024-11-21)

GitHub release

What's Changed

Packaging

• Bump pydantic-core version to v2.27.1 by @sydney-runkle in #10938

Fixes

• Use the correct frame when instantiating a parametrized TypeAdapter by @Viicos in #10893
• Relax check for validated data in default_factory utils by @sydney-runkle in #10909
• Fix type checking issue with model_fields and model_computed_fields by @sydney-runkle in #10911
• Use the parent configuration during schema generation for stdlib dataclasses by @sydney-runkle in #10928
• Use the globals of the function when evaluating the return type of serializers and computed_fields by @Viicos in #10929
• Fix URL constraint application by @sydney-runkle in #10922
• Fix URL equality with different validation methods by @sydney-runkle in #10934
• Fix JSON schema title when specified as '' by @sydney-runkle in #10936
• Fix python mode serialization for complex inference by @sydney-runkle in pydantic-core#1549

New Contributors

v2.10.0 (2024-11-20)

The code released in v2.10.0 is practically identical to that of v2.10.0b2.

GitHub release

See the v2.10 release blog post for the highlights!

What's Changed

Packaging

• Bump pydantic-core to v2.27.0 by @sydney-runkle in #10825
• Replaced pdm with uv by @frfahim in #10727

New Features

• Support fractions.Fraction by @sydney-runkle in #10318
• Support Hashable for json validation by @sydney-runkle in #10324
• Add a SocketPath type for linux systems by @theunkn0wn1 in #10378
• Allow arbitrary refs in JSON schema examples by @sydney-runkle in #10417
• Support defer_build for Pydantic dataclasses by @Viicos in #10313
• Adding v1 / v2 incompatibility warning for nested v1 model by @sydney-runkle in #10431
• Add support for unpacked TypedDict to type hint variadic keyword arguments with @validate_call by @Viicos in #10416
• Support compiled patterns in protected_namespaces by @sydney-runkle in #10522
• Add support for propertyNames in JSON schema by @FlorianSW in #10478
• Adding __replace__ protocol for Python 3.13+ support by @sydney-runkle in #10596
• Expose public sort method for JSON schema generation by @sydney-runkle in #10595
• Add runtime validation of @validate_call callable argument by @kc0506 in #10627
• Add experimental_allow_partial support by @samuelcolvin in #10748
• Support default factories taking validated data as an argument by @Viicos in #10678
• Allow subclassing ValidationError and PydanticCustomError by @Youssefares in pydantic/pydantic-core#1413
• Add trailing-strings support to experimental_allow_partial by @sydney-runkle in #10825
• Add rebuild() method for TypeAdapter and simplify defer_build patterns by @sydney-runkle in #10537
• Improve TypeAdapter instance repr by @sydney-runkle in #10872

Changes

• Don't allow customization of SchemaGenerator until interface is more stable by @sydney-runkle in #10303
• Cleanly defer_build on TypeAdapters, removing experimental flag by @sydney-runkle in #10329
• Fix mro of generic subclass by @kc0506 in #10100
• Strip whitespaces on JSON Schema title generation by @sydney-runkle in #10404
• Use b64decode and b64encode for Base64Bytes type by @sydney-runkle in #10486
• Relax protected namespace config default by @sydney-runkle in #10441
• Revalidate parametrized generics if instance's origin is subclass of OG class by @sydney-runkle in #10666
• Warn if configuration is specified on the @dataclass decorator and with the __pydantic_config__ attribute by @sydney-runkle in #10406
• Recommend against using Ellipsis (...) with Field by @Viicos in #10661
• Migrate to subclassing instead of annotated approach for pydantic url types by @sydney-runkle in #10662
• Change JSON schema generation of Literals and Enums by @Viicos in #10692
• Simplify unions involving Any or Never when replacing type variables by @Viicos in #10338
• Do not require padding when decoding base64 bytes by @bschoenmaeckers in pydantic/pydantic-core#1448
• Support dates all the way to 1BC by @changhc in pydantic/speedate#77

Performance

• Schema cleaning: skip unnecessary copies during schema walking by @Viicos in #10286
• Refactor namespace logic for annotations evaluation by @Viicos in #10530
• Improve email regexp on edge cases by @AlekseyLobanov in #10601
• CoreMetadata refactor with an emphasis on documentation, schema build time performance, and reducing complexity by @sydney-runkle in #10675

Fixes

• Remove guarding check on computed_field with field_serializer by @nix010 in #10390
• Fix Predicate issue in v2.9.0 by @sydney-runkle in #10321
• Fixing annotated-types bound by @sydney-runkle in #10327
• Turn tzdata install requirement into optional timezone dependency by @jakob-keller in #10331
• Use correct types namespace when building namedtuple core schemas by @Viicos in #10337
• Fix evaluation of stringified annotations during namespace inspection by @Viicos in #10347
• Fix IncEx type alias definition by @Viicos in #10339
• Do not error when trying to evaluate annotations of private attributes by @Viicos in #10358
• Fix nested type statement by @kc0506 in #10369
• Improve typing of ModelMetaclass.mro by @Viicos in #10372
• Fix class access of deprecated computed_fields by @Viicos in #10391
• Make sure inspect.iscoroutinefunction works on coroutines decorated with @validate_call by @MovisLi in #10374
• Fix NameError when using validate_call with PEP 695 on a class by @kc0506 in #10380
• Fix ZoneInfo with various invalid types by @sydney-runkle in #10408
• Fix PydanticUserError on empty model_config with annotations by @cdwilson in #10412
• Fix variance issue in _IncEx type alias, only allow True by @Viicos in #10414
• Fix serialization schema generation when using PlainValidator by @Viicos in #10427
• Fix schema generation error when serialization schema holds references by @Viicos in #10444
• Inline references if possible when generating schema for json_schema_input_type by @Viicos in #10439
• Fix recursive arguments in Representation by @Viicos in #10480
• Fix representation for builtin function types by @kschwab in #10479
• Add python validators for decimal constraints (max_digits and decimal_places) by @sydney-runkle in #10506
• Only fetch __pydantic_core_schema__ from the current class during schema generation by @Viicos in #10518
• Fix stacklevel on deprecation warnings for BaseModel by @sydney-runkle in #10520
• Fix warning stacklevel in BaseModel.__init__ by @Viicos in #10526
• Improve error handling for in-evaluable refs for discriminator application by @sydney-runkle in #10440
• Change the signature of ConfigWrapper.core_config to take the title directly by @Viicos in #10562
• Do not use the previous config from the stack for dataclasses without config by @Viicos in #10576
• Fix serialization for IP types with mode='python' by @sydney-runkle in #10594
• Support constraint application for Base64Etc types by @sydney-runkle in #10584
• Fix validate_call ignoring Field in Annotated by @kc0506 in #10610
• Raise an error when Self is invalid by @kc0506 in #10609
• Using core_schema.InvalidSchema instead of metadata injection + checks by @sydney-runkle in #10523
• Tweak type alias logic by @kc0506 in #10643
• Support usage of type with typing.Self and type aliases by @kc0506 in #10621
• Use overloads for Field and PrivateAttr functions by @Viicos in #10651
• Clean up the mypy plugin implementation by @Viicos in #10669
• Properly check for typing_extensions variant of TypeAliasType by @Daraan in #10713
• Allow any mapping in BaseModel.model_copy() by @Viicos in #10751
• Fix isinstance behavior for urls by @sydney-runkle in #10766
• Ensure cached_property can be set on Pydantic models by @Viicos in #10774
• Fix equality checks for primitives in literals by @sydney-runkle in pydantic/pydantic-core#1459
• Properly enforce host_required for URLs by @Viicos in pydantic/pydantic-core#1488
• Fix when coerce_numbers_to_str enabled and string has invalid Unicode character by @andrey-berenda in pydantic/pydantic-core#1515
• Fix serializing complex values in Enums by @changhc in pydantic/pydantic-core#1524
• Refactor _typing_extra module by @Viicos in #10725
• Support intuitive equality for urls by @sydney-runkle in #10798
• Add bytearray to TypeAdapter.validate_json signature by @samuelcolvin in #10802
• Ensure class access of method descriptors is performed when used as a default with Field by @Viicos in #10816
• Fix circular import with validate_call by @sydney-runkle in #10807
• Fix error when using type aliases referencing other type aliases by @Viicos in #10809
• Fix IncEx type alias to be compatible with mypy by @Viicos in #10813
• Make __signature__ a lazy property, do not deepcopy defaults by @Viicos in #10818
• Make __signature__ lazy for dataclasses, too by @sydney-runkle in #10832
• Subclass all single host url classes from AnyUrl to preserve behavior from v2.9 by @sydney-runkle in #10856

New Contributors

• @jakob-keller made their first contribution in #10331
• @MovisLi made their first contribution in #10374
• @joaopalmeiro made their first contribution in #10405
• @theunkn0wn1 made their first contribution in #10378
• @cdwilson made their first contribution in #10412
• @dlax made their first contribution in #10421
• @kschwab made their first contribution in #10479
• @santibreo made their first contribution in #10453
• @FlorianSW made their first contribution in #10478
• @tkasuz made their first contribution in #10555
• @AlekseyLobanov made their first contribution in #10601
• @NiclasvanEyk made their first contribution in #10667
• @mschoettle made their first contribution in #10677
• @Daraan made their first contribution in #10713
• @k4nar made their first contribution in #10736
• @UriyaHarpeness made their first contribution in #10740
• @frfahim made their first contribution in #10727

v2.10.0b2 (2024-11-13)

Pre-release, see the GitHub release for details.

v2.10.0b1 (2024-11-06)

Pre-release, see the GitHub release for details.

... see here for earlier changes.