# `GSLayer.masterLayer`

*Instance Property*

Whether the layer is the master layer for its associated font master.

## Declaration

```swift
var isMasterLayer: Bool { get }
```

```objc
@property (nonatomic, readonly, getter=isMasterLayer) BOOL masterLayer;
```

[See also `isMasterLayer` in the Python API](https://docu.glyphsapp.com/#GSLayer.isMasterLayer)

```python
pyobjc_instanceMethods.isMasterLayer() -> bool
```

## Discussion

Master layers provide the default outline and metrics for a font master.

## See Also

### Layer Kind

- [`GSLayer.anySpecialLayer`](/Core/GlyphsCore/GSLayer/anySpecialLayer) — Whether the layer is a master layer, has special layer attributes, or uses any color-layer format.
- [`GSLayer.braceLayer`](/Core/GlyphsCore/GSLayer/braceLayer) — Whether the layer is an intermediate layer at explicit design-space coordinates.
- [`GSLayer.bracketLayer`](/Core/GlyphsCore/GSLayer/bracketLayer) — Whether the layer is an alternative layer selected by axis rules.
- [`GSLayer.smartComponentLayer`](/Core/GlyphsCore/GSLayer/smartComponentLayer) — Whether the layer is an intermediate layer for a smart glyph.
- [`GSLayer.specialLayer`](/Core/GlyphsCore/GSLayer/specialLayer) — Whether the layer has special layer attributes.