Python UI, without the black box

Build clear, durable interfaces in Python.¶

Hedron gives FastAPI applications a server-rendered UI layer. Compose views in Python, keep ordinary HTTP underneath, and add rich interaction only where it earns its place.

Get started Why Hedron?

FastAPI native Server rendered Progressively enhanced

app.py

00 · Install $ uv add "hedron>=1.0.0" uvicorn 01 · Build

from hedron import Hedron, Text

app = Hedron()

@app.page("/")
def home():
    return Text("Hello, Hedron.")

10 · Run $ uv run uvicorn app:app Build your first app

Choose your starting point¶

Follow the shortest path to the thing you want to build.

Start a new project Install Hedron, scaffold an app, and render your first page. Add Hedron to FastAPI Keep your routes, dependencies, middleware, lifespan, and OpenAPI. Find an API by task Find the right component, route, action, or helper by task. Work from a recipe Use focused patterns for common UI and application workflows.

Browse by goal¶

The documentation follows the way a real project moves from idea to production.

Learn the model Understand pages, views, actions, components, and the request lifecycle. Build an interface Add forms, interactions, data, visuals, authentication, and reusable components. Prepare for production Deploy, test, observe, secure, and scale a production Hedron application. Look something up Look up public APIs, components, configuration, compatibility, and packages.

Current in Hedron¶

Release status, major changes, and practical migration guidance.

Stable release Hedron 1.3.0 is available

Review supported versions, install pins, and package maturity.

Hedron 1.0 One canonical authoring model

Pages, views, and actions now define the stable application model.

Migration guide Moving beyond Streamlit

Translate reruns and session state into explicit routes and interactions.