pytastic 0.0.4

A dependency-free JSON validation library using TypedDict and Annotated

Pytastic

No Magic. Just Python.

Pytastic is a lightweight validation layer that respects your standard Python type hints. If you know TypedDict and Annotated, you already know how to use Pytastic.

Why?

• Zero Dependencies: Pure Python standard library.
• No Learning Curve: It's just standard Python typing.
• IDE Friendly: We use standard types, so your IDE autocompletion works out of the box.

Installation

pip install pytastic

Usage

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

vx = Pytastic()

# 1. Define Schema
class User(TypedDict):
    username: Annotated[str, "min_len=3; regex=^[a-z_]+$"]
    age: Annotated[int, "min=18"]
    role: Literal["admin", "user"]

2. Usage Patterns

Option A: Typed (Recommended)

No registration required. Best for IDE autocompletion.

try:
    user = vx.validate(User, {"username": "tersoo", "age": 25, "role": "admin"})
    print(user)
except Exception as e:
    print(e)

Option B: Dynamic (Requires Registration)

Registration required. Best for quick scripts or cleaner syntax.

vx.register(User)

# Now you can use the class name directly on the validator instance
user = vx.User({"username": "tersoo", "age": 25, "role": "admin"})

3. JSON Schema

# Export standard JSON Schema
print(vx.schema(User))
# Output:
# {
#   "type": "object",
#   "properties": {
#     "username": { "type": "string", "minLength": 3 ... },
#     ...
#   }
# }

License

MIT