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Pytastic

No Magic. Just Python.

Pytastic is a lightweight, dependency-free validation library that respects your standard Python type hints. It compiles TypedDict schemas into highly optimized Python code, making it strictly compliant and faster than many alternatives.

Why Pytastic?

  • Zero Dependencies: Pure Python standard library only.
  • Fast: Uses compiled code generation to beat pydantic.
  • Standard: Uses TypedDict and Annotated from typing.
  • Safe: Strict validation options available.

Performance

Benchmark results (100,000 validation iterations):

Library Time (s) Ops/sec Relative
msgspec 0.053 1,877,872 1.00x
Pytastic 0.179 557,277 3.37x
Pydantic 0.200 499,381 3.76x

Installation

pip install pytastic

Quick Start

from pytastic import Pytastic
from typing import TypedDict, Annotated, Literal

vx = Pytastic()

class User(TypedDict):
    username: Annotated[str, "min_len=3"]
    age: Annotated[int, "min=18"]
    role: Literal["admin", "user"]

# Validate directly
data = {"username": "tersoo", "age": 25, "role": "admin"}
user = vx.validate(User, data)
print(user)

vx.register(User)

# Use as a method on vx
user = vx.User({"username": "tersoo", "age": 25, "role": "admin"})