Static Web

Host Platform Support (Platform support)













When generating a web project, Briefcase produces a static folder of HTML, CSS and JavaScript resources that can be deployed as a web site. The static web site is packaged as a .zip file for distribution.

Although Briefcase provides a run command that can be used to serve the website, this web server is provided as a development convenience. It should not be used in production. If you wish to serve your app in production, you can unzip the .zip file in the root of any web server that can serve static web content.

Web support is experimental!

PyScript (which forms the base of Briefcase’s web backend) is a new project; and Toga’s web backend is very new. As a result this web backend should be considered experimental.

Regardless of what Python version you run Briefcase with, the app will use PyScript’s current Python version (as of October 2022, this is 3.10).

There are also a number of constraints on what you can do in a web environment. Some of these are fundamental constraints on the web as a platform; some are known issues with PyScript and Pyodide as runtime environments. You shouldn’t expect that arbitrary third-party Python packages will “just run” in a web environment.

Icon format

Web projects use a single 32px .png format icon as the site icon.

Web projects do not support splash screens or installer images.

Additional options

The following options can be provided at the command line when producing web projects:


--host <ip or hostname>

The hostname or IP address that the development web server should be bound to. Defaults to localhost.

-p <port> / --port <port>

The port that the development web server should be bound to. Defaults to 8080. If port 8080 is already in use, an arbitrary available port will be used.


Don’t open a web browser after starting the development web server.

Application configuration

The following options can be added to the<appname>.web section of your pyproject.toml file:


Any additional configuration that you wish to add to the pyscript.toml file for your deployed site. For example, you can use this to change the runtime used by Briefcase when deploying your site.

extra_pyscript_toml_content is a string that defines valid TOML content; this content will be parsed, and used to add values to the pyscript.toml generated by Briefcase, overriding any pre-existing keys. For example, to define a custom runtime, and change the default PyScript app name, you could use:

extra_pyscript_toml_content = """
name = "My name override"

src = ""