# Accessing Briefcase packaging metadata at runtime  { #access-packaging-metadata }

When Briefcase installs your app, it adds a [PEP566](https://peps.python.org/pep-0566/) metadata file containing information about your app, and Briefcase itself. You can retrieve this information at runtime using the Python builtin library [`importlib.metadata`][]. `importlib.metadata` was added in Python 3.8; however, it has been backported and published on PyPI as [`importlib.metadata`][] for older versions of Python.

To access application metadata at runtime, you can use the following code:

```python
import sys
try:
    from importlib import metadata as importlib_metadata
except ImportError:
    # Backwards compatibility - importlib.metadata was added in Python 3.8
    import importlib_metadata

# Find the name of the module that was used to start the app
app_module = sys.modules['__main__'].__package__
# Retrieve the app's metadata
metadata = importlib_metadata.metadata(app_module)
```

The `metadata` returned by this code will be a dictionary-like object that contains the following identifying keys:

- **Metadata-Version** - The syntax version of the metadata file itself (as defined in [PEP566](https://peps.python.org/pep-0566/)).
- **Briefcase-Version** - The version of Briefcase used to package the app. The existence of this key in app metadata can be used to identify if your application code is running in a Briefcase container; it will only exist if the app has been packaged by Briefcase.

It will also have the following keys, derived from your application's `pyproject.toml` configuration:

- **Name** - [`app_name`][]
- **Formal-Name** - [`formal_name`][]
- **App-ID** - [`bundle`][] and [`app_name`][], joined with a `.`
- **Version** - [`version`][]
- **Summary** - [`description`][]

The metadata may also contain the following keys, if they have been defined in your app's `pyproject.toml` configuration:

- **Home-page** - [`url`][]
- **Author** - [`author`][]
- **Author-email** - [`author_email`][]

For example, the metadata for the app constructed by the [BeeWare Tutorial](https://tutorial.beeware.org/en/latest/tutorial/tutorial-1) would contain:

```python
Metadata-Version: 2.1
Briefcase-Version: 0.3.1
Name: helloworld
Formal-Name: Hello World
App-ID: com.example.helloworld
Version: 0.0.1
Home-page: https://example.com/helloworld
Author: Jane Developer
Author-email: jane@example.com
Summary: My first application
```
