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Getting Started¶

Welcome to Cello! An ultra-fast Python web framework, powered by Rust. You'll go from zero to a running API in under 5 minutes. Let's build something incredible.

What You'll Build¶

By the end of this guide, you'll have a fully functional REST API running at blazing speed:

app.py
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from cello import App, Response

app = App()

@app.get("/")
def hello(request):
    return {"message": "Hello, World!", "framework": "Cello"}

@app.get("/users/{id}")
def get_user(request):
    user_id = request.params["id"]
    return {"id": user_id, "name": "Jane Doe", "active": True}

@app.post("/users")
def create_user(request):
    data = request.json()
    return Response.json({"created": True, **data}, status=201)

if __name__ == "__main__":
    app.run()
Terminal output
$ python app.py
  ___ ___| | | ___
 / __/ _ \ | |/ _ \   Cello v1.0.1
| (_|  __/ | | (_) |  Rust-powered Python Web Framework
 \___\___|_|_|\___/

Cello running at http://127.0.0.1:8000

Prerequisites¶

Before you begin

Make sure you have the following installed on your system:

Requirement Version Check Command
Python 3.12+ python --version
pip Latest pip --version
Rust toolchain Latest (source builds only) rustc --version

Python 3.12 Required

Cello uses PyO3 with the abi3-py312 flag. Python 3.11 and earlier are not supported.

Setup in 4 Steps¶

  • Install Cello

    Install the framework with a single command.

    pip install cello-framework

    git clone https://github.com/jagadeesh32/cello.git
cd cello && pip install maturin && maturin develop

  • Create Your App

    Create a new file and initialize Cello.

    app.py
    from cello import App

app = App()

  • Add Routes

    Define your endpoints with clean decorators.

    app.py
    @app.get("/")
def hello(request):
    return {"message": "Hello, World!"}

@app.get("/users/{id}")
def get_user(request):
    return {"id": request.params["id"]}

  • Run It

    Start the server and visit your API.

    app.py
    if __name__ == "__main__":
    app.run()

    python app.py
# Visit http://127.0.0.1:8000

Quick Navigation¶

  • Installation

    Detailed installation instructions for all platforms, including virtual environments and troubleshooting.

    Install Guide

  • Quick Start

    A 5-minute walkthrough that covers routes, requests, responses, and your first working API.

    Quick Start

  • First Application

    Build a complete REST API step by step with CRUD operations, error handling, and validation.

    First App

  • Project Structure

    Learn how to organize your Cello project for small scripts, medium apps, and large-scale services.

    Structure

  • Configuration

    Configure your application for development, testing, and production environments.

    Configuration

Next Steps¶

Once you've built your first app, explore these areas to level up:

  • Explore Features

    Discover routing, middleware, security, real-time, and more.

    Features

  • Learn with Tutorials

    Build a REST API, chat app, auth system, and microservices.

    Tutorials

  • Browse Examples

    Copy-paste examples from basic to enterprise-grade apps.

    Examples

Join the Cello Community

Have questions? Want to share what you're building? Join the community:

We'd love to hear from you!