Liquid Glass API Reference for SwiftUI

Contents

• Overview
• glassEffect(_:in:)
• Glass
• GlassEffectContainer
• glassEffectID(_:in:)
• glassEffectUnion(id:namespace:)
• glassEffectTransition(_:)
• GlassEffectTransition
• Button Styles
• DefaultGlassEffectShape
• Scroll Edge Effect
• Background Extension (Split Views)
• Availability Gating
• Performance Guidelines
• Accessibility Considerations
• Best Practices Summary
• Apple Documentation Links

Overview

Liquid Glass is a dynamic translucent material available on iOS 26.0+, iPadOS 26.0+, macOS 26.0+, Mac Catalyst 26.0+, tvOS 26.0+, and watchOS 26.0+. It blurs content behind it, reflects color and light from surrounding content, and reacts to touch and pointer interactions in real time. Standard SwiftUI components (tab bars, toolbars, navigation bars, sheets, popovers) adopt Liquid Glass automatically when built with the latest SDK.

This reference covers the complete API surface for applying Liquid Glass to custom views.

glassEffect(_:in:)

Applies the Liquid Glass effect behind a view.

nonisolated func glassEffect(
    _ glass: Glass = .regular,
    in shape: some Shape = DefaultGlassEffectShape()
) -> some View

The system renders a shape anchored behind the view with the Liquid Glass material and applies foreground effects over the view content. The default shape is Capsule.

Apply this modifier after other modifiers that affect the view's appearance (padding, frame, font, foregroundStyle).

Basic usage

Text("Hello, World!")
    .font(.title)
    .padding()
    .glassEffect()

Custom shape

Text("Hello, World!")
    .font(.title)
    .padding()
    .glassEffect(in: .rect(cornerRadius: 16.0))

Common shapes: .capsule (default), .rect(cornerRadius:), .circle.

Tinted and interactive

Text("Hello, World!")
    .font(.title)
    .padding()
    .glassEffect(.regular.tint(.orange).interactive())

Glass

A structure that defines the configuration of the Liquid Glass material. Conforms to Equatable, Sendable, and SendableMetatype.

Type Properties

Instance Methods

Methods are chainable:

.glassEffect(.regular.tint(.blue).interactive())

GlassEffectContainer

A view that combines multiple Liquid Glass shapes into a single rendering pass. Enables blending and morphing between individual shapes.

@MainActor @preconcurrency
struct GlassEffectContainer<Content> where Content : View

Conforms to View, Sendable, SendableMetatype.

Initializer

init(spacing: CGFloat, @ViewBuilder content: () -> Content)

The spacing parameter controls how glass shapes interact:

• Larger spacing: Shapes begin blending at greater distances; morphing starts sooner.
• Smaller spacing: Shapes must be closer before blending occurs.

Match the container spacing to the interior layout spacing so shapes remain separate at rest but merge during animated transitions.

Example

GlassEffectContainer(spacing: 40.0) {
    HStack(spacing: 40.0) {
        Image(systemName: "scribble.variable")
            .frame(width: 80.0, height: 80.0)
            .font(.system(size: 36))
            .glassEffect()

        Image(systemName: "eraser.fill")
            .frame(width: 80.0, height: 80.0)
            .font(.system(size: 36))
            .glassEffect()
    }
}

glassEffectID(_:in:)

Associates a stable identity with a Liquid Glass effect for morphing during view hierarchy transitions.

nonisolated func glassEffectID(
    _ id: (some Hashable & Sendable)?,
    in namespace: Namespace.ID
) -> some View

Use with @Namespace, GlassEffectContainer, and withAnimation to animate shapes morphing into each other when views appear or disappear.

Morphing example

@State private var isExpanded = false
@Namespace private var namespace

var body: some View {
    GlassEffectContainer(spacing: 40.0) {
        HStack(spacing: 40.0) {
            Image(systemName: "scribble.variable")
                .frame(width: 80.0, height: 80.0)
                .font(.system(size: 36))
                .glassEffect()
                .glassEffectID("pencil", in: namespace)

            if isExpanded {
                Image(systemName: "eraser.fill")
                    .frame(width: 80.0, height: 80.0)
                    .font(.system(size: 36))
                    .glassEffect()
                    .glassEffectID("eraser", in: namespace)
            }
        }
    }

    Button("Toggle") {
        withAnimation {
            isExpanded.toggle()
        }
    }
    .buttonStyle(.glass)
}

glassEffectUnion(id:namespace:)

Merges multiple views into a single Liquid Glass shape. All effects with the same shape, Glass variant, and union ID combine into one rendered shape.

@MainActor @preconcurrency func glassEffectUnion(
    id: (some Hashable & Sendable)?,
    namespace: Namespace.ID
) -> some View

Useful for dynamically created views or views outside a shared layout container.

Example

@Namespace private var namespace
let symbols = ["cloud.bolt.rain.fill", "sun.rain.fill", "moon.stars.fill", "moon.fill"]

GlassEffectContainer(spacing: 20.0) {
    HStack(spacing: 20.0) {
        ForEach(symbols.indices, id: \.self) { i in
            Image(systemName: symbols[i])
                .frame(width: 80.0, height: 80.0)
                .font(.system(size: 36))
                .glassEffect()
                .glassEffectUnion(id: i < 2 ? "weather" : "night", namespace: namespace)
        }
    }
}

glassEffectTransition(_:)

Controls how a glass effect appears or disappears during view hierarchy changes.

@MainActor @preconcurrency func glassEffectTransition(
    _ transition: GlassEffectTransition
) -> some View

GlassEffectTransition

A structure describing changes when a glass effect is added to or removed from the view hierarchy. Conforms to Sendable and SendableMetatype.

Type Properties

Example with explicit transition

if isExpanded {
    Image(systemName: "note")
        .frame(width: 20, height: 20)
        .glassEffect()
        .glassEffectID("note", in: namespace)
        .glassEffectTransition(.materialize)
}

Button Styles

SwiftUI provides two built-in Liquid Glass button styles.

GlassButtonStyle

Standard glass appearance for buttons.

Button("Action") { }
    .buttonStyle(.glass)

GlassProminentButtonStyle

A more prominent glass appearance for primary actions.

Button("Confirm") { }
    .buttonStyle(.glassProminent)

These button styles automatically include interactivity (touch/pointer reactions). Prefer these over manually applying .glassEffect(.regular.interactive()) to buttons.

DefaultGlassEffectShape

The default shape used by glassEffect(_:in:) when no shape is specified. Resolves to Capsule.

Scroll Edge Effect

Configures the scroll edge effect style for scroll views within a view hierarchy.

nonisolated func scrollEdgeEffectStyle(
    _ style: ScrollEdgeEffectStyle?,
    for edges: Edge.Set
) -> some View

Available styles include .soft (soft edge) and .hard. System bars adopt this automatically. Apply to custom bars that float over scrollable content.

.scrollEdgeEffectStyle(.soft, for: .top)

Background Extension (Split Views)

Extend content visually under sidebars and inspectors by duplicating the view into mirrored copies with a blur effect applied on top:

NavigationSplitView {
    // sidebar content
} detail: {
    ZStack {
        BannerView()
            .backgroundExtensionEffect()
    }
}

Also available as backgroundExtensionEffect(isEnabled:) for conditional use. Apply with discretion — typically to a single background view in the detail column.

Availability Gating

All Liquid Glass APIs require iOS 26.0+. Always provide a fallback:

if #available(iOS 26, *) {
    content
        .padding()
        .glassEffect(.regular, in: .rect(cornerRadius: 16))
} else {
    content
        .padding()
        .background(.ultraThinMaterial, in: RoundedRectangle(cornerRadius: 16))
}

Performance Guidelines

• Use GlassEffectContainer to batch multiple glass effects into a single render pass.
• Limit the total number of glass effects visible on screen at once.
• Avoid creating many separate GlassEffectContainer instances when one can suffice.
• Profile with Instruments to check rendering performance.

Accessibility Considerations

• Test with Reduce Transparency enabled (glass effects adapt automatically for standard components; verify custom implementations).
• Test with Reduce Motion enabled (morphing and fluid animations are simplified).
• Ensure sufficient contrast for text and icons rendered over glass.
• Standard components from SwiftUI adapt to these settings automatically.

Best Practices Summary

1. Use GlassEffectContainer when multiple glass views coexist.
2. Apply .glassEffect() after layout and appearance modifiers.
3. Match container spacing to interior layout spacing.
4. Use .interactive() only on tappable/focusable elements.
5. Use withAnimation when toggling views with glassEffectID for morphing.
6. Prefer .buttonStyle(.glass) / .buttonStyle(.glassProminent) for buttons.
7. Avoid overusing Liquid Glass -- reserve it for key functional elements.
8. Always gate with if #available(iOS 26, *) and provide fallback UI.
9. Test with Reduce Transparency and Reduce Motion accessibility settings.

Apple Documentation Links

• Applying Liquid Glass to custom views
• Adopting Liquid Glass
• Landmarks: Building an app with Liquid Glass
• View.glassEffect(_:in:)
• Glass
• GlassEffectContainer
• GlassEffectTransition
• GlassButtonStyle
• GlassProminentButtonStyle