---
title: Observable
framework: observation
role: symbol
role_heading: Protocol
path: observation/observable
---

# Observable

A type that emits notifications to observers when underlying data changes.

## Declaration

```swift
protocol Observable
```

## Mentioned in

Applying Macros

## Overview

Overview Conforming to this protocol signals to other APIs that the type supports observation. However, applying the Observable protocol by itself to a type doesn’t add observation functionality to the type. Instead, always use the Observable() macro when adding observation support to a type.

## See Also

### Observable conformance

- [Observable()](observation/observable().md)