Viicos — on the record

FastAPI & Pydantic

wire 2026-11-09

Pydantic fixes GC tracking in pydantic-core and caches UTC TzInfo

Fix more issues about GC tracking in `pydantic-core` pydantic/pydantic
Cache UTC `TzInfo` instance pydantic/pydantic

FastAPI & Pydantic

wire 2026-11-08

Pydantic drops Python 3.10, accepts list and DecimalTuple for Decimal

Drop support for Python 3.10 (#14250) pydantic/pydantic
Support list and `DecimalTuple` inputs for `Decimal` (#14249) pydantic/pydantic

FastAPI & Pydantic

wire 2026-11-07

Pydantic reworks `TypeAdapter` call arguments, tightens `Decimal` schemas

Change the arguments schema for `@validate_call` pydantic/pydantic

FastAPI & Pydantic

wire 2026-11-06

FastAPI bumps pillow and dnspython, Pydantic corrects arguments JSON Schema

Fix JSON Schema for `arguments` schema pydantic/pydantic

FastAPI & Pydantic

wire 2026-11-05

Pydantic measures duplicate TypedDict schema cost, FastAPI drops conference rail

Use entry points API in the plugin loader pydantic/pydantic

FastAPI & Pydantic

wire 2026-11-04

Pydantic targets schema-build fast paths, adds large-string JSON benchmarks

Add benchmarks for serializing large strings to JSON pydantic/pydantic
Add benchmarks for serializing large strings to JSON (#14207) pydantic/pydantic

FastAPI & Pydantic

wire 2026-11-03

Pydantic caches fixed core schemas, and its schema path skips dispatch for builtin scalars

Bump Ruff to 0.17.3 pydantic/pydantic

FastAPI & Pydantic

wire 2026-11-02

Serialization hot paths trimmed, ByteSize human_readable fixed at boundaries

Improve performance of model serialization pydantic/pydantic
Improve performance of dict serialization pydantic/pydantic
Improve performance of type inference during serialization pydantic/pydantic
Fix `ByteSize.human_readable()` showing `1024.0KiB` instead of `1.0MiB` just below a unit boundary pydantic/pydantic

FastAPI & Pydantic

wire 2026-11-01

Pydantic deletes the V1 escape hatch

Remove `pydantic.v1` namespace (#14156) pydantic/pydantic
Remove V1 backwards compatibility and functionality deprecated since 2.0 (#14139) pydantic/pydantic
Remove functionality deprecated during the 2.x timeline (#14158) pydantic/pydantic
Remove the `__validators__` argument of `create_model()` and the `validate_on_init` dataclass parameter (#14163) pydantic/pydantic

FastAPI & Pydantic

wire 2026-10-31

model_fields_set moves to a bitset; real-world model corpora enter the benchmark suite

Improve performance of `model_fields_set` pydantic/pydantic

FastAPI & Pydantic

wire 2026-10-29

Pydantic writes down its threat model and starts enforcing mapping max_length

Check mapping `max_length` constraint during validation pydantic/pydantic
Add security policy and threat model pydantic/pydantic

FastAPI & Pydantic

wire 2026-10-27

Lazy reprs in nested union serialization, and a dependency train

Lazily call repr of values during nested union serialization pydantic/pydantic
Publish `pydantic-core` wheels for PyPy 8.0 (`pp80` ABI) pydantic/pydantic

FastAPI & Pydantic

wire 2026-10-24

FastAPI stops inferring False for omitted boolean form fields

Fix `Self` resolution in parametrized generics pydantic/pydantic
Bump PyO3 to 0.30.1, jiter to 0.18.0, use `PyFrozenDict` pydantic/pydantic

FastAPI & Pydantic

wire 2026-10-23

FastAPI 0.160.0 widens the blast radius of parameter model extras

Fix forward annotations evaluation and type variables substitution when rebuilding parametrized generic models pydantic/pydantic
Fix pickling of `PydanticCustomError` and `ValidationError`s containing custom errors pydantic/pydantic
Do not extract attribute docstrings from nested classes and functions pydantic/pydantic

FastAPI & Pydantic

wire 2026-10-21

FastAPI 0.155.0 removes the deprecated **extra escape hatch

Support named tuples in `Sequence` serialization pydantic/pydantic

FastAPI & Pydantic

wire 2026-10-20

FastAPI 0.150.0 treats empty file inputs as missing

Implement recursion guard for `validate_strings()` (#14029) pydantic/pydantic
Fix infinite recursion when validating an invalid default with `PydanticUseDefault` pydantic/pydantic

FastAPI & Pydantic

wire 2026-10-16

FastAPI fixes blocking frontend fallback checks

Bump speedate to v0.18.0 pydantic/pydantic

FastAPI & Pydantic

wire 2026-10-15

pydantic-core GC traversal and unpickling fixes land

Fix various issues about GC tracking in `pydantic-core` pydantic/pydantic
Fix unpickling of generic classes defined in separate module pydantic/pydantic
Support explicit `by_alias` overriding `validate_by_alias` in validation JSON schemas pydantic/pydantic
Honor `ser_json_inf_nan` in Python serialization with `mode=json` pydantic/pydantic
Harden CI pydantic/pydantic

FastAPI & Pydantic

wire 2026-10-12

Pydantic fixes JSON Schema cache key mismatch

Fix JSON Schema cache key mismatch with nested `json_schema_mode_override` pydantic/pydantic
Fix docs conversion table pydantic/pydantic
Improve release script pydantic/pydantic

FastAPI & Pydantic

wire 2026-10-11

Pydantic tightens timedelta and Decimal validation

Reject out-of-range int inputs for `timedelta` pydantic/pydantic
Enforce the `max_digits` whole-digits limit in the Python `Decimal` validator pydantic/pydantic

FastAPI & Pydantic

wire 2026-10-10

Pydantic restores TypedDict inheritance, patches a Python 3.10.0 ForwardRef crash

Support `closed` and `extra_items` via inheritance in `TypedDict` pydantic/pydantic
Fix `TypeError` on `ForwardRef` on Python 3.10.0 (#13964) pydantic/pydantic
Harden CI security pydantic/pydantic
Support `closed` and `extra_items` via inheritance in `TypedDict` (#13967) pydantic/pydantic

FastAPI & Pydantic

wire 2026-10-09

FastAPI 0.143.0 makes OTel auto-setup opt-in, Pydantic 2.14 lands

v2.14.0 2026-10-08 pydantic/pydantic
Avoid Python tuple allocation during model fields validation pydantic/pydantic
Fix `arguments-v3` schema with variadic keywords pydantic/pydantic

FastAPI & Pydantic

wire 2026-10-08

FastAPI isolates telemetry for excluded requests, Pydantic prepares 2.14.0

Revert "Respect config in `TypeAdapter.json_schemas()` (#13890)" pydantic/pydantic
Prepare release v2.14.0 pydantic/pydantic
Avoid validating URL prefix multiple times in multi host URLs pydantic/pydantic
Reject large exponents in `Fraction` validation pydantic/pydantic

FastAPI & Pydantic

wire 2026-10-07

SQLModel ships 0.0.48 with SQLAlchemy 2.1 support

Rebuild incomplete types during serialization inference pydantic/pydantic
Handle exceptions during `Decimal` validation pydantic/pydantic

FastAPI & Pydantic

wire 2026-10-05

Pydantic clears lazy import xfails, enables frame pointers

Explicitly enable frame pointers (#13896) pydantic/pydantic

FastAPI & Pydantic

wire 2026-10-03

FastAPI absorbs a 14-package dependency bump, docs translations land in four languages

Fix third-party tests (#13924) pydantic/pydantic

FastAPI & Pydantic

wire 2026-10-02

Pydantic survives ZoneInfo OS errors, FastAPI’s bothousekeeping continues

Handle OS errors during `ZoneInfo` validation pydantic/pydantic

FastAPI & Pydantic

wire 2026-10-01

FastAPI survives an OpenTelemetry failure, pydantic adds create_model namespace

Add `__namespace__` parameter to `create_model()` pydantic/pydantic
Convert annotation to footnote in documentation pydantic/pydantic

FastAPI & Pydantic

wire 2026-09-30

FastAPI 0.142.0 ships native OpenTelemetry support

Don't apply `ser_json_timedelta` to all datetime types in serialization inference pydantic/pydantic
Encode JSON Schema defaults with a consistent configuration pydantic/pydantic
Propagate `init` and `kw_only=False` from `Field()` to stdlib dataclass fields pydantic/pydantic

FastAPI & Pydantic

wire 2026-09-26

Pydantic adds multiple_of for Fraction and timedelta

Add support for `multiple_of` constraint in `fraction` and `timedelta` core schemas pydantic/pydantic
Add support for `multiple_of` constraint in `fraction` and `timedelta` core schemas (#13873) pydantic/pydantic

FastAPI & Pydantic

wire 2026-09-25

Pydantic stops mutating model_config; docs drop the social plugin

Do not mutate `model_config` attribute pydantic/pydantic
Remove Mkdocs `social` plugin pydantic/pydantic
Fix PyPy 8.0.0 test failure (#13863) pydantic/pydantic
Remove Mkdocs `social` plugin (#13865) pydantic/pydantic

FastAPI & Pydantic

wire 2026-09-23

SQLModel 0.0.46 ships timedelta fix for UTC datetimes

Catch `OverflowError` during `ByteSize` validation (#13850) pydantic/pydantic
Catch `OverflowError` during `ByteSize` validation pydantic/pydantic

FastAPI & Pydantic

wire 2026-09-18

Two new pydantic core schemas, counter and ordered-dict

Add a `counter` core schema pydantic/pydantic
Add an `ordered-dict` core schema pydantic/pydantic

FastAPI & Pydantic

wire 2026-09-17

Pydantic docs examples stop passing silently, debug Python target lands in CI

Fix documentation examples not raising and remove unused `string_sub_type` unused error code pydantic/pydantic
Add a debug Python test target in CI (#13820) pydantic/pydantic
Add a debug Python test target in CI pydantic/pydantic
Fix documentation examples not raising and remove unused `string_sub_type` unused error code (#13821) pydantic/pydantic

FastAPI & Pydantic

wire 2026-09-15

Pydantic patches its PyEmscripten CI job

Fix PyEmscripten CI job (#13805) pydantic/pydantic
Document `url_preserve_empty_path` in network types (#13804) pydantic/pydantic

FastAPI & Pydantic

wire 2026-09-14

Pydantic repairs its PyEmscripten CI job

Fix PyEmscripten CI job (#13805) pydantic/pydantic
Fix PyEmscripten CI job pydantic/pydantic

FastAPI & Pydantic

wire 2026-09-12

Pydantic calls enum constructors in both validation modes

Call enum constructors in both validation modes pydantic/pydantic
Call enum constructors in both validation modes (#13792) pydantic/pydantic

FastAPI & Pydantic

wire 2026-09-11

Pydantic aligned enum constructors with both validation modes

Call enum constructors in both validation modes pydantic/pydantic
Call enum constructors in both validation modes (#13792) pydantic/pydantic

FastAPI & Pydantic

wire 2026-09-10

Pydantic stabilizes MISSING sentinel, adds TypeForm support

Stabilize `MISSING` sentinel pydantic/pydantic
Add support for `TypeForm` pydantic/pydantic
Refactor `Decimal` JSON Schema `pattern` constraint pydantic/pydantic
Fix race conditions in freethreaded build pydantic/pydantic
Add support for lazy imports pydantic/pydantic

FastAPI & Pydantic

wire 2026-09-09

Pydantic adds deque core schema

Add a `deque` core schema pydantic/pydantic

FastAPI & Pydantic

wire 2026-09-08

Fix Mypy plugin crash with import cycle, close constraint inconsistencies

Fix Mypy plugin crash with import cycle pydantic/pydantic
Fix inconsistencies between constraints and core schemas allowed values (#13772) pydantic/pydantic
Fix supported constraints for types of `datetime` module (#13768) pydantic/pydantic

FastAPI & Pydantic

wire 2026-09-07

Pydantic fixes Mypy plugin crash, tightens datetime constraints

Fix Mypy plugin crash with import cycle pydantic/pydantic
Fix supported constraints for types of `datetime` module (#13768) pydantic/pydantic

FastAPI & Pydantic

wire 2026-09-03

Pydantic hardens JSON mode serialization error handling

Handle any exception when trying to compute JSON Schema default pydantic/pydantic

FastAPI & Pydantic

wire 2026-09-02

Dependency churn across FastAPI and SQLModel, decimal validation hardening in Pydantic

Do not rely on normalization to validate decimals pydantic/pydantic

FastAPI & Pydantic

wire 2026-08-30

Pydantic signature honors validate_by_alias, GC checks harden core suite

Check GC traversal completeness when constructing validators and serializers in tests pydantic/pydantic
Check GC traversal completeness when constructing validators and serializers in tests (#13626) pydantic/pydantic

FastAPI & Pydantic

wire 2026-08-29

Pydantic 2.13.5 fixes GC, smart union counting; SQLModel deprecates min_items

v2.13.5 pydantic/pydantic
Bump twine to v7.0.0 pydantic/pydantic
Bump `pypa/gh-action-pypi-publish` action to v1.14.2 pydantic/pydantic

FastAPI & Pydantic

wire 2026-08-28

Pydantic Core Is Poised For A Speed Leap

Improve permormance of `FieldInfo` construction pydantic/pydantic
Move schema gathering logic to `pydantic-core` pydantic/pydantic
Add support for `frozendict` type pydantic/pydantic
Allow `dict`, `frozendict` and `frozenset` as `defaultdict` default factories pydantic/pydantic

FastAPI & Pydantic

wire 2026-08-26

CI CACHE GOES DARK ACROSS FASTAPI AND SQLMODEL

Clarify note about plain model serializers returning a non-dict pydantic/pydantic

FastAPI & Pydantic

wire 2026-08-25

PYDANTIC FIXES SERIALIZER EXCLUSION BUG

Do not drop include/exclude if serializer wasn't called (#13702) pydantic/pydantic
Support `populate_by_name` in `@validate_call` pydantic/pydantic
Add additional tests for forward references resolving pydantic/pydantic
Add new docs publish CI (#13700) pydantic/pydantic

FastAPI & Pydantic

wire 2026-08-19

Pydantic opens serialization to any core schema

Allow any `CoreSchema` to be used as serialization pydantic/pydantic
Improve performance of `GenerateSchema.generate_schema()` dispatching pydantic/pydantic

FastAPI & Pydantic

wire 2026-08-18

Pydantic Reworks Type References

Refactor type references logic pydantic/pydantic
Fix third-party tests pydantic/pydantic

FastAPI & Pydantic

wire 2026-08-17

PYDANTIC FIXES DISCRIMINATED UNIONS AND VALIDATOR PIPELINE BUGS

Support bare `None` annotation for discriminated unions pydantic/pydantic
Fix application of other constraints in the pipeline API pydantic/pydantic
Respect runtime alias validation configuration when wrap validators are present pydantic/pydantic

FastAPI & Pydantic

wire 2026-08-14

PYDANTIC PATCHES PYODIDE LOCKFILE DEPENDENCY

Fix Pyodide lockfile (#13654) pydantic/pydantic
Fix Pyodide lockfile pydantic/pydantic

FastAPI & Pydantic

wire 2026-08-13

PYDANTIC FIXES GENERIC ALIAS CRASHES, SQLMODEL AND FASTAPI MIGRATE LABEL INFRASTRUCTURE

Do not error on unhashable generic aliases during core schema generation pydantic/pydantic
Bump `click` to v8.4.2 pydantic/pydantic
Workaround circular import error in Mypy pydantic/pydantic
Update Pyodide lockfile pydantic/pydantic
Update Pyodide lockfile (#13649) pydantic/pydantic

FastAPI & Pydantic

wire 2026-08-12

PYDANTIC PATCHES GARBAGE COLLECTION LEAKS IN CORE STRUCTS

Fix missing GC traversal on some `pydantic-core` struct fields pydantic/pydantic
Fix missing GC traversal in `pydantic-core` for `GeneralFieldsSerializer` (#13629) pydantic/pydantic

FastAPI & Pydantic

wire 2026-08-11

TIANGOLO CONSOLIDATES CI ACROSS FASTAPI AND SQLMODEL, PYDANTIC TIGHTENS TYPE INTROSPECTION

Bump `typing-inspection` to v0.4.3 (#13618) pydantic/pydantic

FastAPI & Pydantic

wire 2026-08-09

TIANGOLO LOCKS DOWN WORKFLOW TOKENS ACROSS FASTAPI AND SQLMODEL

Fix support for callable discriminators with PEP 695 type aliases pydantic/pydantic
Fix support for callable discriminators with PEP 695 type aliases (#13604) pydantic/pydantic

FastAPI & Pydantic

wire 2026-08-07

PYDANTIC EYES PYTHON 3.15, FASTAPI AND SQLMODEL CLEAN HOUSE

Add initial support for Python 3.15 pydantic/pydantic
Refactor model namespace inspection pydantic/pydantic
Prepare release v2.14.0b1 pydantic/pydantic

FastAPI & Pydantic

wire 2026-08-06

PYDANTIC TIGHTENS NAMED TUPLE VALIDATION, FASTAPI PULLS 12 DEPENDENCY UPDATES

Add a `named-tuple` core schema pydantic/pydantic
Raise explicit `TypeError` on invalid `index_key` serialization wrap handler pydantic/pydantic

FastAPI & Pydantic

wire 2026-08-05

PYDANTIC TUNES MODEL BUILDING FOR SPEED WHILE FASTAPI HARDENS CRYPTO

Migrate `pydantic-core` tests to main tests directory pydantic/pydantic
Split stdlib types tests into dedicated test files pydantic/pydantic

FastAPI & Pydantic

wire 2026-08-04

PYDANTIC TACKLES CORE SCHEMA PERFORMANCE WHILE FASTAPI DOCS GET A UI FIX

Optimize type lookup logic in core schema generation pydantic/pydantic
Add support for `EllipsisType` pydantic/pydantic
Allow reuse of validators when plugins are set pydantic/pydantic
Fix serialization of `ValidateAs` (#13487) pydantic/pydantic

FastAPI & Pydantic

wire 2026-08-01

PYDANTIC FIXES SERIALIZATION INFO EXCLUSION BUG

Fix population of `SerializationInfo.exclude_computed_fields` (#13560) pydantic/pydantic
Fix population of `SerializationInfo.exclude_computed_fields` pydantic/pydantic

FastAPI & Pydantic

wire 2026-07-31

PYDANTIC ADDS MCP AND FASTMCP TO THIRD PARTY TEST SUITE

Add MCP Python SDK and FastMCP third party tests pydantic/pydantic

FastAPI & Pydantic

wire 2026-07-30

FASTAPI 0.141.0 SHIPS WITH SMARTER LOCAL DEV, PYDANTIC CUTS VALIDATOR MEMORY BY 25%

Bump dependencies for Python 3.15 compatibility pydantic/pydantic
Fix application of constraints in pipeline API pydantic/pydantic

FastAPI & Pydantic

wire 2026-07-28

FASTAPI DITCHES DEPENDENCY FLATTENING, CUTS OPENAPI GENERATION BLOAT

Fix access of annotations in `safe_get_annotations()` in Python <= 3.13 (#13521) pydantic/pydantic

FastAPI & Pydantic

wire 2026-07-22

FASTAPI AND PYDANTIC SHIFT TO UV FOR DOCS AND DEPENDENCIES

Fix Skill layout pydantic/pydantic

FastAPI & Pydantic

wire 2026-07-21

PYDANTIC FIXES TYPE VARIABLE BUG IN SUBCLASS GENERICS

Fix type variable substitution in `__pydantic_extra__` with subclasses pydantic/pydantic
Fix type variable substitution in `__pydantic_extra__` with subclasses (#13483) pydantic/pydantic

FastAPI & Pydantic

wire 2026-07-18

PYDANTIC TIGHTENS TYPE CHECKER ALIGNMENT AHEAD OF NEXT RELEASE

Bump mypy to 2.3.0, pyright to 1.1.411 pydantic/pydantic
Tweaks to Logfire references pydantic/pydantic

FastAPI & Pydantic

wire 2026-07-14

FASTAPI AND SQLMODEL LOCK DOWN DEPENDENCY MANAGEMENT, PYDANTIC MYPY PLUGIN GETS PRECISION FIXES

Skip `RootModel.__init__()` in Mypy plugin pydantic/pydantic
Defer placeholders in Mypy plugin pydantic/pydantic

FastAPI & Pydantic

wire 2026-07-05

FASTAPI AND SQLMODEL PATCH CRITICAL GITHUB ACTIONS FLAW ACROSS THE STACK

Cache `ModelPrivateAttr.default_factory_takes_validated_data` property pydantic/pydantic

FastAPI & Pydantic

wire 2026-07-04

PYDANTIC PATCHES TYPE VARIABLE BUG AS FASTAPI EXPANDS HINDI DOCS

Fix type variable substitution in `__pydantic_extra__` pydantic/pydantic

FastAPI & Pydantic

wire 2026-06-30

FASTAPI TIGHTENS STATIC FILE HANDLING, PYDANTIC ADDS FRACTION SUPPORT

Support `Fraction` type in `pydantic-core` pydantic/pydantic
Add agent skills pydantic/pydantic

FastAPI & Pydantic

wire 2026-06-11

FASTAPI HOUSEKEEPING SWEEP CLEARS INACTIVE SPONSORS

Add Slack link to docs pydantic/pydantic

FastAPI & Pydantic

wire 2026-06-09

PYDANTIC CLOSES GAP ON DEFAULT FACTORY VALIDATION, SQLMODEL INHERITS SQLALCHEMY FIX

Handle missing errors with default factories taking validated data pydantic/pydantic

FastAPI & Pydantic

wire 2026-06-08

PYDANTIC FIXES DEFAULT FACTORY VALIDATION BUG, SQLALCHEMY PATCHES ORM ISSUE

Handle missing errors with default factories taking validated data pydantic/pydantic

FastAPI & Pydantic

wire 2026-05-29

AUTHLIB FIXES REDIRECT VULNERABILITY, PYTHON-MULTIPART SHIPS PERFORMANCE WIN

Update documentation links pydantic/pydantic

FastAPI & Pydantic

wire 2026-05-23

PYDANTIC SHIPS 2.14.0a1 WITH PYEMSCRIPTEN SUPPORT AS TIANGOLO REPOS CONSOLIDATE CONFIGS

Add PyEmscripten platform tag support pydantic/pydantic