serve.md

Build Hello World App

Welcome to the "Build Hello World App" tutorial! Get ready to dive into the world of Panel and serve your very first app.

Serve the App

Let's get started by serving our simple Hello World app using Panel. Choose a tab below to continue:

:::::{tab-set}

::::{tab-item} Script :sync: script

In this section, we'll create the simplest Panel .py app:

import panel as pn

pn.extension()

pn.panel("Hello World").servable()

:::{note} Here's a breakdown of the code:

• panel: The Panel python package, conventionally imported as pn.

• pn.extension(): Loads javascript dependencies and configures Panel.

• pn.panel(...): Creates a displayable Panel component.

• .servable(): Displays the component in a server app. :::

Copy the code into a file named app.py and save it. Then, run the Panel server in your terminal with:

panel serve app.py --dev

::::

::::{tab-item} Notebook :sync: notebook

In this section, we'll create the simplest Panel Notebook app:

import panel as pn

pn.extension()

pn.panel("Hello World").servable()

:::{note} Here's what the code does:

• panel: The Panel python package, conventionally imported as pn.

• pn.extension(): Loads the pyviz_comms notebook extension, loads javascript dependencies and configures Panel.

• pn.panel(...): Creates a displayable Panel component, which can be directly displayed in the notebook.

• .servable(): Displays the component in a server app. :::

Copy the above code cells into a clean notebook named app.ipynb. Run the cells and save the notebook as app.ipynb.

Then, run the Panel server in your terminal with:

panel serve app.ipynb --dev

:::::

Upon successful startup, you'll see the server's URL in the terminal.

2024-01-17 21:05:32,338 Starting Bokeh server version 3.3.3 (running on Tornado 6.4)
2024-01-17 21:05:32,339 User authentication hooks NOT provided (default user enabled)
2024-01-17 21:05:32,342 Bokeh app running at: http://localhost:5006/app
2024-01-17 21:05:32,342 Starting Bokeh server with process id: 42008

Open your browser at that URL to view the app. It should look like

.

Play around with the app by modifying the "Hello World" text, saving the file and observe how it updates in real-time. To stop the server, simply press CTRL+C in the terminal.

Recap

Congratulations on serving your first Panel app! Let's recap what we've learned:

• How to serve a Python script or Notebook using panel serve app.py or panel serve app.ipynb, respectively.

• How to enable auto reload with the --dev flag.

• How to stop the Panel server with CTRL+C.

Resources

Tutorials

• Serve Panel Apps (Intermediate)

How-to

• Launch a server dynamically with pn.serve or pn.show

• Launch a server on the command line

• Migrate from Streamlit | Serve Apps

• Serve multiple applications with pn.serve

• Serve static files with --static-dirs

• Serve with Django

• Serve with FastAPI

• Serve with Flask

• Write and serve apps in Markdown

Keep exploring and building with Panel! 🚀