Effortlessly build performant APIs

with Litestar

In the ever-evolving world of web development, Python has established itself as a versatile and powerful programming language. Various Python web frameworks, such as Flask, Django, and FastAPI, have gained popularity for their unique features and capabilities. Among these frameworks, LiteStar is a relatively new player that aims to provide a lightweight and flexible alternative for web developers. In this blog post, we’ll explore what LiteStar is, how it compares to Flask, and provide some examples to help you get started.

What is LiteStar?

LiteStar is a Python web framework designed for simplicity and flexibility. It is open-source and built with the goal of being easy to learn and use, making it an excellent choice for both beginners and experienced developers. LiteStar follows the WSGI (Web Server Gateway Interface) standard, which means it can run on various web servers and is compatible with popular Python web server gateways like Gunicorn and uWSGI.

LiteStar vs. Flask: What’s the Difference?

LiteStar shares some similarities with Flask, another popular Python web framework known for its minimalistic approach. However, there are key differences that set LiteStar apart:

1. Project Philosophy:

LiteStar aims to keep its core codebase simple and minimal, allowing developers to add only the features they need. Flask follows a similar philosophy but provides more built-in functionality.

2. Flexibility:

LiteStar emphasizes flexibility by allowing developers to choose and integrate components as needed, enabling them to build custom solutions. Flask provides a more opinionated structure, which can be advantageous for beginners but might limit flexibility for advanced use cases.

3. Middleware System:

LiteStar provides a middleware system that allows you to define custom middleware to handle various aspects of request/response processing. Flask also has middleware capabilities, but LiteStar’s implementation may provide more control.

4. Extensions and Ecosystem:

Flask boasts a wide range of extensions and a well-established ecosystem, making it easy to find third-party tools and libraries. While LiteStar’s ecosystem is growing, it may not have the same level of maturity and diversity as Flask’s.

LiteStar Examples

Let’s dive into some LiteStar examples to see how it works. First, you’ll need to install LiteStar using pip:

pip install litestar

Now, let’s create a simple LiteStar application:

First, create a file named app.py with the following contents:

from litestar import Litestar, get


@get("/")
async def index() -> str:
    return "Hello, world!"


@get("/books/{book_id:int}")
async def get_book(book_id: int) -> dict[str, int]:
    return {"book_id": book_id}


app = Litestar([index, get_book])

Let’s break down the code and explain its components

Importing LiteStar and Required Functions:

from litestar import Litestar, get

This line imports the LiteStar class and the get decorator from the LiteStar framework. LiteStar is the main application class, and get is a decorator used for defining routes that handle HTTP GET requests.

Defining Route Handlers:

@get("/")
async def index() -> str:
    return "Hello, world!"

This code block defines a route handler for the root URL (“/”). When a user accesses the root URL of the web application, the index function is executed. It returns a string, “Hello, world!”, as the response. The @get("/") decorator indicates that this route handler handles HTTP GET requests to the root URL.

Parameterized Route Handler:

@get("/books/{book_id:int}")
async def get_book(book_id: int) -> dict[str, int]:
    return {"book_id": book_id}

Here, another route handler is defined for URLs like “/books/123”, where “123” is a dynamic value representing the book_id. The {book_id:int} syntax within the route indicates that book_id should be an integer. When a user accesses a URL matching this pattern, the get_book function is called with the book_id extracted from the URL. It then returns a dictionary containing the book_id as an integer.

Creating the LiteStar Application:

app = Litestar([index, get_book])

This line creates an instance of the Litestar application, passing in a list of route handlers (index and get_book). These handlers will be used to determine how to respond to incoming HTTP requests.

Then, run the following command:

litestar run
# Or you can run Uvicorn directly:
uvicorn app:app --reload

You can now visit http://localhost:8000/ and http://localhost:8000/books/1 in your browser and you should see the JSON responses of your two endpoints:

"Hello, world!"

and

{"book_id": 1}

Tip

You can also check out the automatically generated OpenAPI-based documentation at:

http://localhost:8000/schema (for ReDoc),
http://localhost:8000/schema/swagger (for Swagger UI),
http://localhost:8000/schema/elements (for Stoplight Elements)

You can check out a more in-depth tutorial in the Developing a basic TODO application section!

Philosophy

Litestar is a community-driven project. This means not a single author, but rather a core team of maintainers is leading the project, supported by a community of contributors. Litestar currently has 5 maintainers and is being very actively developed.
Litestar draws inspiration from NestJS — a contemporary TypeScript framework — which places opinions and patterns at its core.
While still allowing for function-based endpoints, Litestar seeks to build on Python’s powerful and versatile OOP, by placing class-based controllers at its core.
Litestar is not a microframework. Unlike frameworks such as FastAPI, Starlette, or Flask, Litestar includes a lot of functionalities out of the box needed for a typical modern web application, such as ORM integration, client- and server-side sessions, caching, OpenTelemetry integration, and many more. It’s not aiming to be “the next Django” (for example, it will never feature its own ORM), but its scope is not micro either.

Conclusion:

LiteStar is a promising addition to the Python web framework landscape, offering simplicity, flexibility, and a minimalistic approach to web development. While it shares some similarities with Flask, it stands out with its emphasis on giving developers more control over their applications. If you’re looking for a lightweight and adaptable framework for your Python web projects, LiteStar is definitely worth exploring.

As with any technology, the choice between LiteStar and Flask depends on your project’s specific requirements and your personal preferences. Both frameworks have their strengths, and the right choice will depend on the unique needs of your application.

Exploring LiteStar: A Python Framework for Lightweight Web Development