Pydantic v2 Pydantic v2 (released 2023-06, current stable 2.13 as of 2026-04-19, paired with Python 3.10-3.14 including 3.14 free-threaded builds) is a near-complete rewrite on (Rust). API is similar but not identical to v1 -- several v1 patterns silently break or behave differently. This skill documents the v2 idioms, the v1 migration gotchas, and the FastAPI integration surface. Notable recent releases: - 2.11 (2025): 2x schema build-time improvements, 2-5x memory reduction for nested models, PEP 695/696 generic syntax, experimental free-threaded Python 3.13, / / config ( pending v3 depreca…