FastAPI dropped Pydantic v1 support. If your APIs still use v1, here’s everything that breaks, what changes in v2’s Rust core, and a full migration checklist with code examples.
You try to use a dict as a key. Python raises TypeError: unhashable type. Python 3.13 finally has the answer: frozendict — immutable, hashable, built-in.
Python 3.14 is here. t-strings, lazy annotationlib, and locals() fixes shipped in Python 3.14 on October 7, 2025 — here’s what you need to know.
Python Dataclasses: The Complete 2026 Guide — From @dataclass to slots, frozen, and __post_init__
April 26, 2026
Stop writing 30 lines of __init__, __repr__, __eq__ for data classes. Python’s dataclasses (added in 3.7) handle all of it with a single decorator — here’s the complete guide.
Astral’s new ty type checker claims 10–100× speed over mypy. We tested it against pyright and mypy — benchmarks, setup guide, and who should switch now vs. wait for stable.
In Parts 1-3, you mastered Python’s type() function, learned type hints and annotations, and discovered when to use duck typing versus static typing. Now it’s time to level up with advanced type patterns that separate junior developers from senior ones. Previous parts in this series…
