---
title: "StableMarker"
description: "[StableMarker] marks an annotation as indicating a type is stable. A stable type obeys the
following assumptions,
1) The result of [equals] will always return the same result for the same two instances.
2) When a public property of the type changes, composition will be notified.
3) All public property types are stable.

A type that is immutable obeys the above assumptions because the public values will never change.
The [Immutable] annotation is provided to mark immutable types as stable.

An object whose public properties do not change but is not immutable (for example, it has private
mutable state or uses property delegation to a [androidx.compose.runtime.MutableState] object,
but is otherwise immutable), should use the [Stable] annotation.

Mutable object that do not notify composition when they changed should not be marked as stable.

When all types passed as parameters to a [androidx.compose.runtime.Composable] function are
marked as stable then the parameter values are compared for equality based on positional
memoization and the call is skipped if all the values are the equal to the previous call.

Primitive value types (such as Int, Float, etc), String and enum types are considered, a priori,
stable."
type: "class"
---

<div class='type'>Class</div>


<a id='references'></a>

<div class='sourceset sourceset-common'>Common</div>


```kotlin
@MustBeDocumented
@Target(AnnotationTarget.ANNOTATION_CLASS, AnnotationTarget.CLASS)
public annotation class StableMarker
```


`StableMarker` marks an annotation as indicating a type is stable. A stable type obeys the
following assumptions,
1) The result of `equals` will always return the same result for the same two instances.
2) When a public property of the type changes, composition will be notified.
3) All public property types are stable.

A type that is immutable obeys the above assumptions because the public values will never change.
The `Immutable` annotation is provided to mark immutable types as stable.

An object whose public properties do not change but is not immutable (for example, it has private
mutable state or uses property delegation to a `androidx.compose.runtime.MutableState` object,
but is otherwise immutable), should use the `Stable` annotation.

Mutable object that do not notify composition when they changed should not be marked as stable.

When all types passed as parameters to a `androidx.compose.runtime.Composable` function are
marked as stable then the parameter values are compared for equality based on positional
memoization and the call is skipped if all the values are the equal to the previous call.

Primitive value types (such as Int, Float, etc), String and enum types are considered, a priori,
stable.