> ## Documentation Index
> Fetch the complete documentation index at: https://anki.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Add-on Config

## Config JSON

Add-ons can store config data in a JSON dictionary. You provide the
default values by shipping a file called `config.json`. A simple example:

```text theme={null}
{"myvar": 5}
```

In config.md:

```text theme={null}
This is documentation for this add-on's configuration, in *markdown* format.
```

In your add-on’s code:

```python theme={null}
from aqt import mw
config = mw.addonManager.getConfig(__name__)
print("var is", config['myvar'])
```

If the config hasn't been customized, the default values from that file will be used.

If you need to programmatically modify the config, you can save your
changes with:

```python theme={null}
mw.addonManager.writeConfig(__name__, config)
```

Users are also able to edit the config inside the GUI.

The edited config is stored in `meta.json`.

When `getConfig()` is used after edits, meta.json is used preferentially. If a key
is missing from meta.json's config, Anki will fall back on the default config.

If you change the value of existing keys in config.json, users who have
customized their configuration will continue to see the old values
unless they use the "restore defaults" button.

If no config.json file exists, getConfig() will return None - even if
you have called writeConfig().

Add-ons that manage options in their own GUI can have that GUI displayed
when the config button is clicked:

```python theme={null}
mw.addonManager.setConfigAction(__name__, myOptionsFunc)
```

Avoid key names starting with an underscore - they are reserved for
future use by Anki.

## User Files

When your add-on needs configuration data other than simple keys and
values, it can use a special folder called user\_files in the root of
your add-on’s folder. Any files placed in this folder will be preserved
when the add-on is upgraded. All other files in the add-on folder are
removed on upgrade.

To ensure the user\_files folder is created for the user, you can put a
README.txt or similar file inside it before zipping up your add-on.

When Anki upgrades an add-on, it will ignore any files in the .zip that
already exist in the user\_files folder.