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Single-file apps (pip evaluators)

Run these without cloning the monorepo. Requires Python 3.10+ and a working network for pip install. Prefer Build your first app (hedron new) for the interactive Hello + Refresh first-hour path.

Same scaffold as hedron new — includes HTMX Refresh.

Docs simulation — click Refresh status for an HTMX-style fragment swap (no server).

Hedron

Hello from hedron new

All systems operational · refreshed __HEDRON_SIM_UTC__
Click — timestamp updates
Docs simulation of <code>127.0.0.1:8000</code> — click <strong>Refresh status</strong> for an HTMX-style fragment swap (no server).

What hedron new writes as app.py (the real app, not the docs simulator):

app.py
import os
from datetime import datetime, timezone

from hedron import Hedron, Page, Stack, Text, ToastHost, html

app = Hedron(
    title="Hedron App",
    security="standard",
    explorer="off",
    session_secret=os.environ.get("HEDRON_SESSION_SECRET", "replace-in-production"),
)


@app.view("/status")
def status():
    stamp = datetime.now(timezone.utc).strftime("%H:%M:%S UTC")
    return html.div(
        Text(f"All systems operational · refreshed {stamp}"),
        role="status",
        aria={"live": "polite"},
    )


@app.action("/ping", fallback="/")
def ping():
    from hedron import refresh

    return refresh(status).toast("Refreshed")


@app.page("/")
def home() -> Page:
    return Page(
        Stack(
            Text("Hello from hedron new"),
            status(),
            status.refresh_button("Refresh status"),
            ping.button("Ping"),
            ToastHost(),
        ),
        title="Home",
    )

Use @app.page, @app.view, and @app.action as the canonical 1.0 function roles. Use explicit Page + @app.page when you need full Page constructor control — see the Hedron API.

pip install "hedron>=1.0.0" "uvicorn[standard]"
# paste the Code tab into app.py, then:
uvicorn app:app --reload

Static Hello only (no Refresh)

Minimal page with no HTMX Refresh — use only if you want the smallest possible file.

pip install "hedron>=1.0.0" "uvicorn[standard]"

Save as app.py:

from hedron import Hedron, Text

app = Hedron(title="Demo", security="standard", session_secret="replace-me")


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

uvicorn app:app --reload

Open http://127.0.0.1:8000.

CSRF form

Prefer @app.action with a typed FormBody boundary for validated forms (see quickstart CRUD scaffold). Follow the pasteable form in Minimal form POST when you need explicit Form / CsrfField.

Live clock (polling)

Follow the pasteable app in Live interaction (“poll a clock”).

When you need the monorepo

Clone for Flask/Django reference apps, the team-admin reference app, and HDJ progressive examples: Runnable examples.