AffineUI for Python

A small, HTML5-compliant, GPU-accelerated UI renderer with an integrated component framework — a native replacement for Electron and Qt, for Python.

Think Gradio, but native: describe your UI as a tree of typed components, get a real HTML/CSS renderer with a browser-quality cascade, animations, hit-testing, and 120 Hz paint — all in one binary, no browser embedded, no JavaScript runtime, no Electron. Bootstrap and Tailwind-style stylesheets render out of the box; the bundled default is Decius CSS.

Status: alpha. Broad standards coverage, real UIs run today, but expect bugs and expect APIs to move.

Note: this release carries no -alpha suffix in its version number, but AffineUI is alpha and pre-1.0. Features, APIs, and the set of supported platforms are all still in flux.

Verified on: Linux (Ubuntu, x86-64), macOS (Apple Silicon), and Windows (x86-64) — the full suite (600+ tests) passes on each. Other platforms and architectures are not yet supported.

Install

pip install affineui

Prebuilt wheels ship for CPython 3.9 – 3.13 on Linux (manylinux_2_28 x86_64), macOS (universal2 — Intel + Apple Silicon), and Windows AMD64.

For a source install from a clone of the main repo:

pip install ./bindings/python           # regular install
pip install -e ./bindings/python        # editable / dev

Hello, world

Component API (recommended)

import affineui as ui

view = ui.View(ui.ViewTheme.Decius)
view.begin()
view.heading(1, "Hello from Python")
view.paragraph("AffineUI — native HTML/CSS, no browser, no JS.")
view.button("Click me", primary=True, key="go").on_click(lambda: print("clicked!"))
view.end()

app = ui.App(title="Hello", width=720, height=480)
app.load_view(view)
raise SystemExit(app.run())

Raw HTML

import affineui as ui

app = ui.App(title="Hello", width=720, height=480)
app.load_html("""
  <main style="padding: 24px; font-family: sans-serif;">
    <h1>Hello from Python</h1>
    <p>AffineUI is alive.</p>
    <button>Click me</button>
  </main>
""")
raise SystemExit(app.run())

Headless (no window — for CI and tests)

import affineui as ui

doc = ui.document(
    "<main><h1>Hello</h1><p>Layout without a window.</p></main>",
    "main { padding: 16px; } h1 { font-size: 32px; }",
    width=640, height=360,
)
print(ui.version(), doc.content_size())

A modest app

A live-updating counter — state lives in Python; the reconciler diffs your view and patches the DOM in place. CSS hover/focus/animation keeps running between updates.

import affineui as ui

count = 0
app = ui.App(title="Counter", width=480, height=240)

def build_view() -> ui.View:
    view = ui.View(ui.ViewTheme.Decius)
    view.begin()
    view.heading(1, f"Count: {count}")
    view.button("Increment", primary=True, key="inc").on_click(bump)
    view.button("Reset",                    key="reset").on_click(reset)
    view.end()
    return view

def bump():
    global count
    count += 1
    app.load_view(build_view())

def reset():
    global count
    count = 0
    app.load_view(build_view())

app.load_view(build_view())
raise SystemExit(app.run())

The main repo's bindings/python/examples/ ships larger runnable programs — a component gallery, a photo editor, and a full Bootstrap-styled panel demo.

Loading design-system CSS

Decius CSS is the default when you use the component API. To render your own HTML with a framework stylesheet, tell the app where its asset folder is:

app = ui.App(
    title="Bootstrap demo",
    width=1280,
    height=720,
    asset_folders=["examples"],          # so href="frameworks/..." resolves
)
app.load_html("""
  <link rel="stylesheet" href="frameworks/css/bootstrap-5.3.8.min.css">
  <div class="container py-4">
    <button class="btn btn-primary">Native Bootstrap</button>
  </div>
""")
raise SystemExit(app.run())

Bootstrap 4.6 / 5.3, Tailwind-style utility classes, and Ant-style component markup all render — this is a real CSS engine, not an HTML-shaped layout solver.

What AffineUI is not

• Not a browser. No navigation, no fetch, no cookies.
• Not a nerfed HTML5. Missing non-esoteric features are bugs.
• Not a security sandbox. Never feed it untrusted HTML/CSS/JS.
• Not an everything-included framework. No video decode, no audio, no 3D — those are your app's job.
• Not (yet) a JS runtime. JS + React support is on the roadmap as an opt-in extension.

See the main README for the full picture, embedding notes, C++ / Rust / C# APIs, and the demo gallery.

Links

• Repository: https://github.com/affineui/affineui
• Docs: https://github.com/affineui/affineui/tree/main/docs
• Issues: https://github.com/affineui/affineui/issues
• Discussion: r/affineui — questions, show-and-tell, and general chat
• License: MIT