element-51

element-51 lets a Python author design a node-editor GUI. You describe the nodes with ordinary typed functions or classes. The library serves an editor in the browser, keeps the authoritative graph in your Python process, and runs it when asked. It is for people who want a graphical way to wire up computations, such as a pipeline builder, a small visual tool for a team, or a control panel that a script can also drive.

Quick start

$ uv add element-51

import element_51


@element_51.node
def number() -> float:
    return 21.0


class Double(element_51.Node):
    value: float = 0.0

    def run(self) -> float:
        return self.value * 2


app = element_51.App([number, Double])
first = app.add_node(number, x=60, y=80)
second = app.add_node(Double, x=320, y=80)
app.add_link(first, "out", second, "value")
element_51.serve(app, open_browser=True)

Your browser opens on the editor. Press Run: number shows 21.0 and Double shows 42.0. The same graph is available in Python: app.run() returns the value of every output, and app.save("graph.json") and app.load("graph.json") keep it between sessions.

Tick Run automatically beside Run to run the graph 300 ms after each edit instead. A node that failed gets a red border, and the banner says why.