[android-components](../../../index.md) / [mozilla.components.service.fretboard](../../index.md) / [Experiment](../index.md) / [Matcher](index.md) / [appId](./app-id.md)

# appId

`val appId: `[`String`](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-string/index.html)`?` [(source)](https://github.com/mozilla-mobile/android-components/blob/master/components/service/fretboard/src/main/java/mozilla/components/service/fretboard/Experiment.kt#L55)

id (package name) of the expected application, as a regex

