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")