Lihil  /ˈliːhaɪl/ — a performant, productive, and professional web framework with a vision:

Making Python the mainstream programming language for web development.

Lihil is

• Performant: lihil is fast, 50%-100% faster than ASGI frameworks offering similar functionalities, even more with its own server. see benchmarks

• Productive: ergonomic API with strong typing support and built-in solutions for common problems — along with beloved features like openapi docs generation — empowers users to build their apps swiftly without sacrificing extensibility.

• professional: Start small, move fast, achieve great, lihil follows industry standards (RFC9110, 9457, ...) and best practices (EDA, service choreography, etc) to deliver robust and scalable solutions.

Features

• Data validation using msgspec, which is about 12x faster than pydantic v2 for valiation and 25x memory efficient than pydantic v2, see benchmarks
• Advanced dependency injection, using ididi written in cython, inject params, resources, plugins, extremly powerful and fast.
• OpenAPI docs and json schema automatically generated with accurate type information, union type, json examples, problem detail(RFC-9457) and more.
• Great Testability, lihil is designed to be tested, however you want, web framework specifics objects such as Response, content-type is abstracted away(you can still use them) via Marks, you can test your endpoints like regular functions.
• Strong support for AI featuers, lihil takes AI as a main usecase, AI related features such as SSE, remote handler will be well supported, there will also be tutorials on how to develop your own AI agent/chatbot using lihil.

checkout features page for detailed explaination with scrrenshot & code examples.

First impression

from lihil import Lihil, Route, EventBus, Event, status
from msgspec import field, Struct

from .users.infra import UserService

user_route = Route("/users")

class UserSignup(Payload):
    id: str = field(default_factory=lambda: str(uuid.uuid4()))
    name: str

class UserCreated(Event):
    id: str
    name: str

@user_route.post
async def singup_user(
    data: UserSignup, service: UserService, bus: EventBus
) -> Resp[str, status.Created]:
    user = await service.signup(data)
    event = UserCreated(id=user.id, name=user.name)
    await bus.publish(event)
    return user.id

lhl = Lihil(routes=[user_route])

if __name__ == "__main__":
    lhl.run()

Install

lihil(currently) requires python>=3.12

pip

pip install lihil

uv

if you want to install this project with uv

uv install guide

1. init your web project with project_name

uv init project_name

1. install lihil via uv, this will solve all dependencies for your in a dedicated venv.

uv add lihil

versioning

lihil follows semantic versioning, where a version in x.y.z represents:

• x: major, breaking change
• y: minor, feature updates
• z: patch, bug fixes, typing updates

v1.0.0 will be the first stable major version.