Note
Build faster with Reflex:
- AI Builder - Generate full-stack Reflex apps in seconds.
- Agent Toolkit - Connect MCP and Skills to your coding assistant.
- App Management - Deploy and manage your Reflex apps.
Reflex is a library to build full-stack web apps in pure Python.
Key features:
- Pure Python - Write your app's frontend and backend all in Python, no need to learn Javascript.
- Full Flexibility - Reflex is easy to get started with, but can also scale to complex apps.
See our architecture page to learn how Reflex works under the hood.
Important: We strongly recommend using a virtual environment to ensure the reflex command is available in your PATH.
Create a project, add Reflex, and start the development server with uv:
mkdir my_app_name
cd my_app_name
uv init
uv add reflex
uv run reflex init
uv run reflex runYou should see your app running at http://localhost:3000.
Now you can modify the source code in my_app_name/my_app_name.py. Reflex has fast refreshes so you can see your changes instantly when you save your code.
Build an image generation app in Python with Reflex: define the UI, manage state in a class, and call an image model from an event handler.
reflex-dalle-video-2x.mp4
import reflex as rx import openai client = openai.AsyncOpenAI() class State(rx.State): prompt: str = "" image_url: str = "" processing: bool = False @rx.event def set_prompt(self, value: str): self.prompt = value @rx.event async def generate(self): self.processing = True yield response = await client.images.generate( model="gpt-image-1.5", prompt=self.prompt, ) self.image_url = f"data:image/png;base64,{response.data[0].b64_json}" self.processing = False def index(): return rx.vstack( rx.heading("Image Generator"), rx.input(placeholder="Enter a prompt...", on_change=State.set_prompt), rx.button("Generate", on_click=State.generate, loading=State.processing), rx.image(src=State.image_url), ) app = rx.App() app.add_page(index, title="Reflex:Image Generation")