Who contributed to FastAPI & Pydantic on October 28, 2026?

1 developer shipped this update, including davidhewitt.

What were the notable FastAPI & Pydantic updates?

Make JSON validation by iteration consistent with Python approach and Make JSON validation by iteration consistent with Python approach (#13275).

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Oct 28, 2026

$ the-wire · showcase

Pydantic aligns JSON validate-by-iteration with Python

By RepoJournal · Filed 06:58 UTC on October 28, 2026 · About FastAPI & Pydantic · Composed from the cited sources · methodology

1 person shipped this

davidhewitt @davidhewitt 2 cited

Pydantic fixed three divergences in the 2.13 JSON "validate by iteration" pathway, so JSON and Python input now route extras and aliases the same way.

Make JSON validation by iteration consistent with Python approach pydantic/pydantic

by davidhewitt

The fix addresses three separate mismatches: extra matches for a field now land in `__pydantic_extra__` when more than one alias or name is present, extras are validated after fields, and extra validation now runs through any `extras_key_validator`. David Hewitt added a `py_and_json` test parameterisation so the same cases run under both modes.

Make JSON validation by iteration consistent with Python approach (#13275) pydantic/pydantic

by David Hewitt

The commit lands as a single change to the iteration path, co-authored with Viicos, so code relying on 2.13's JSON iteration behavior for aliased or extra fields may see different placement and validation order.

$ ls fastapi/reviews/ # the step-back reads

the week in review Pydantic drops Python 3.10, then layers serialization fast paths the month in review Five Pydantic validation bypasses and a quadratic URL check

Full archive → Weekly reviews →

Quick answers

What shipped in FastAPI & Pydantic on October 28, 2026?: Pydantic fixed three divergences in the 2.13 JSON "validate by iteration" pathway, so JSON and Python input now route extras and aliases the same way. In total, 1 commits and 1 pull requests landed.
Who contributed to FastAPI & Pydantic on October 28, 2026?: 1 developer shipped this update, including davidhewitt.
What were the notable FastAPI & Pydantic updates?: Make JSON validation by iteration consistent with Python approach and Make JSON validation by iteration consistent with Python approach (#13275).

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$ log FastAPI & Pydantic --recent

2026-11-09 Pydantic fixes GC tracking in pydantic-core and caches UTC TzInfo 50 shipped 2026-11-08 Pydantic drops Python 3.10, accepts list and DecimalTuple for Decimal 37 shipped 2026-11-07 Pydantic reworks `TypeAdapter` call arguments, tightens `Decimal` schemas 13 shipped 2026-11-06 FastAPI bumps pillow and dnspython, Pydantic corrects arguments JSON Schema 6 shipped

$ log --all # elsewhere on the wire

Agent Security 2026-11-09 Quiet day in agent security as guard coverage reaches four clients Alignment & Post-training 2026-11-09 verl defaults Ascend RL mode, open-instruct unblocks SFT packing

$ ls showcases/

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