Dotnet Uno Targets

dotnet-uno-targets

Per-target deployment guidance for Uno Platform applications: Web/WASM, iOS, Android, macOS (Catalyst), Windows, Linux (Skia/GTK), and Embedded (Skia/Framebuffer). Each target section covers project setup, debugging workflow, packaging/distribution, platform-specific gotchas, AOT/trimming implications, and behavior differences from other targets.

Scope boundary: This skill owns per-target deployment, debugging, packaging, and platform-specific gotchas. Core Uno Platform development (Extensions, MVUX, Toolkit, themes) is owned by [skill:dotnet-uno-platform]. MCP integration for live docs is owned by [skill:dotnet-uno-mcp].

Out of scope: Uno Platform testing (Playwright for WASM, platform Appium tests) -- see [skill:dotnet-uno-testing]. General AOT/trimming patterns -- see [skill:dotnet-aot-wasm]. UI framework selection -- see [skill:dotnet-ui-chooser].

Cross-references: [skill:dotnet-uno-platform] for core development, [skill:dotnet-uno-mcp] for MCP integration, [skill:dotnet-uno-testing] for testing, [skill:dotnet-aot-wasm] for general WASM AOT patterns, [skill:dotnet-ui-chooser] for framework selection.

Target Platform Overview

TFM note: Use version-agnostic globs (net*-ios, net*-android) when detecting platform targets programmatically to avoid false negatives on older or newer TFMs.

Web/WASM

Project Setup

# Run the WASM target
dotnet run -f net8.0-browserwasm --project MyApp/MyApp.csproj

The WASM target renders XAML controls in the browser. The renderer depends on project configuration: Skia (canvas/WebGL) or native HTML mapping. The app loads via a JavaScript bootstrap (uno-bootstrap.js) that initializes the .NET WASM runtime.

Debugging

• Browser DevTools: Use F12 in Chrome/Edge to inspect DOM, network, console output
• .NET debugging: Visual Studio and VS Code support debugging the .NET WASM runtime via browser CDP
• Uno DevServer: dotnet run starts a development server with live reload support
• Console logging: ILogger output appears in the browser console

Packaging/Distribution

# Publish for production
dotnet publish -f net8.0-browserwasm -c Release --output ./publish

# Output is a static site (HTML/JS/WASM)
# Deploy to: Azure Static Web Apps, GitHub Pages, Netlify, any static host

Published output is a self-contained static site. No server-side runtime required.

Platform Gotchas

• No filesystem access: Use browser storage APIs (IndexedDB, localStorage) via JS interop or Uno.Storage
• Threading limitations: Web Workers provide limited multi-threading; Task.Run may not parallelize on WASM
• CORS restrictions: HTTP requests from WASM are subject to browser CORS policy
• Initial load time: The .NET WASM runtime and assemblies must download before the app is usable. Use assembly trimming to reduce download size. AOT improves runtime execution speed but increases artifact size
• Deep linking: Configure URL routing in the Uno Navigation Extensions for browser URL bar navigation

AOT/Trimming

Trimming reduces download size by removing unused code. AOT pre-compiles IL to WebAssembly, improving runtime execution speed but increasing artifact size. Use both together and measure the tradeoffs for your app.

<PropertyGroup Condition="'$(TargetFramework)' == 'net8.0-browserwasm'">
  <WasmShellMonoRuntimeExecutionMode>InterpreterAndAOT</WasmShellMonoRuntimeExecutionMode>
  <RunAOTCompilation>true</RunAOTCompilation>
</PropertyGroup>

Trimming is critical for WASM. Untrimmed apps can exceed 30MB. With trimming, typical apps are 5-15MB. AOT adds to the artifact size but eliminates interpreter overhead at runtime -- profile both download time and execution speed in target conditions.

For Uno-specific AOT gotchas (linker descriptors, Uno source generators), see the AOT section. For general WASM AOT patterns, see [skill:dotnet-aot-wasm].

Behavior Differences

• Navigation: URL-based deep linking works natively; route maps should define URL patterns
• Authentication: OAuth flows use browser redirects (popup or redirect); no native browser available. Token storage uses browser secure storage
• Debugging: Full .NET debugger available via CDP; breakpoints work in Visual Studio/VS Code
• File pickers: Use browser file input APIs; FileOpenPicker maps to <input type="file">

iOS

Project Setup

# Build for iOS simulator
dotnet build -f net8.0-ios

# Run on simulator
dotnet run -f net8.0-ios

Requires Xcode installed on macOS. The renderer (Skia or native) depends on project configuration and Uno version.

Debugging

• Visual Studio (Pair to Mac) / VS Code + C# Dev Kit / Rider: Attach to iOS simulator or device
• Xcode Instruments: Profile CPU, memory, and energy usage
• Hot Reload: Supported via DOTNET_MODIFIABLE_ASSEMBLIES=debug

Packaging/Distribution

# Publish for App Store
dotnet publish -f net8.0-ios -c Release \
  /p:CodesignKey="Apple Distribution: MyCompany" \
  /p:CodesignProvision="MyApp Distribution Profile"

Distribution channels: App Store (requires Apple Developer account), TestFlight (beta testing), Ad Hoc (enterprise).

Required: Provisioning profiles, signing certificates, entitlements file for capabilities (push notifications, HealthKit, etc.).

Platform Gotchas

• No JIT compilation: iOS prohibits JIT. All code must be AOT-compiled or interpreted. The .NET runtime uses the Mono interpreter by default
• Provisioning profiles: Must match bundle ID, team ID, and entitlements. Expired profiles cause cryptic build failures
• Background execution: iOS restricts background processing. Use BGTaskScheduler for background work
• App Transport Security (ATS): HTTPS required by default; HTTP requires an NSAppTransportSecurity exception in Info.plist
• Memory pressure: iOS aggressively kills background apps. Handle MemoryWarning events

AOT/Trimming

iOS requires AOT by default (no JIT). The .NET runtime compiles to native ARM64 code.

<PropertyGroup Condition="$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)')) == 'ios'">
  <PublishTrimmed>true</PublishTrimmed>
  <TrimMode>link</TrimMode>
</PropertyGroup>

Gotcha: Reflection-heavy code fails silently on iOS. Test with trimming enabled during development, not just for release builds.

Behavior Differences

• Navigation: Gesture-based back navigation (swipe from left edge) is automatic with Uno Navigation
• Authentication: Uses ASWebAuthenticationSession for OAuth; biometric auth via LocalAuthentication framework
• Debugging: Simulator is fast; device debugging requires USB connection and provisioning. Remote debugging with Hot Reload supported

Android

Project Setup

# Build for Android
dotnet build -f net8.0-android

# Deploy to connected device or emulator
dotnet run -f net8.0-android

Requires Android SDK (installed via dotnet workload install android or Android Studio).

Debugging

• Android Emulator: Use Android Studio's emulator or command-line emulator
• ADB (Android Debug Bridge): adb logcat for runtime logs, adb devices to verify connections
• Visual Studio / VS Code: Full debugging with breakpoints on emulator or device

Packaging/Distribution

# Publish signed APK/AAB (use env vars or CI secrets for passwords — never hardcode)
dotnet publish -f net8.0-android -c Release \
  /p:AndroidKeyStore=true \
  /p:AndroidSigningKeyStore=mykey.keystore \
  /p:AndroidSigningStorePass="$ANDROID_KEYSTORE_PASS" \
  /p:AndroidSigningKeyAlias=myalias \
  /p:AndroidSigningKeyPass="$ANDROID_KEY_PASS"

Google Play requires Android App Bundle (AAB) format. Sideloading uses APK.

Platform Gotchas

• SDK version targeting: <SupportedOSPlatformVersion> controls minimum API level. Target API 34+ for Google Play compliance
• Runtime permissions: Dangerous permissions (camera, location, storage) require runtime requests. Check and request in code, not just manifest
• Activity lifecycle: Android destroys activities on rotation by default. Uno handles this, but custom native code must be lifecycle-aware
• ProGuard/R8: Code shrinking may remove reflection targets. Use @Keep annotations or linker configuration for native interop types

AOT/Trimming

<PropertyGroup Condition="$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)')) == 'android'">
  <PublishTrimmed>true</PublishTrimmed>
  <RunAOTCompilation>true</RunAOTCompilation>
</PropertyGroup>

AOT on Android improves startup time. Unlike iOS, JIT is available as fallback for untrimmed code paths.

Behavior Differences

• Navigation: Hardware/software back button triggers Uno navigation back. BackRequested event fires automatically
• Authentication: Uses CustomTabs (Chrome) for OAuth; biometric auth via AndroidX.Biometric
• Debugging: Emulator is slower than iOS Simulator but supports more API levels. Use hardware acceleration (HAXM/KVM) for performance

macOS (Catalyst)

Project Setup

# Build for macOS
dotnet build -f net8.0-maccatalyst

# Run on macOS
dotnet run -f net8.0-maccatalyst

Uses Mac Catalyst (iOS APIs adapted for macOS). Requires Xcode on macOS.

Debugging

• Visual Studio (Pair to Mac) / VS Code + C# Dev Kit / Rider: Native macOS debugging
• Xcode Instruments: Profile performance and memory
• Console.app: View system logs for the app process

Packaging/Distribution

# Publish for distribution
dotnet publish -f net8.0-maccatalyst -c Release \
  /p:CodesignKey="Developer ID Application: MyCompany" \
  /p:CodesignProvision="MyApp Mac Profile"

Distribution channels: Mac App Store, direct download with notarization, enterprise deployment.

Notarization required: macOS Gatekeeper requires notarized apps for distribution outside the App Store. Use xcrun notarytool to submit.

Platform Gotchas

• Sandbox restrictions: Mac App Store apps run in a sandbox. File access requires entitlements and user grants
• Catalyst limitations: Not all iOS APIs translate to macOS. Check SupportedOSPlatform attributes
• Menu bar: macOS expects a proper menu bar. Uno provides default menus; customize via platform-specific code
• Window management: macOS apps support multiple windows. Uno's single-window model may need adaptation for multi-window scenarios

AOT/Trimming

Same profile as iOS (AOT by default for Catalyst). Trimming recommended for distribution builds.

Behavior Differences

• Navigation: No swipe-back gesture; relies on toolbar back button or keyboard shortcuts (Cmd+[)
• Authentication: Uses ASWebAuthenticationSession (shared with iOS); supports Touch ID via Secure Enclave
• Debugging: Native macOS process; standard .NET debugging tools work. No simulator -- runs as native app

Windows

Project Setup

# Build for Windows
dotnet build -f net8.0-windows10.0.19041

# Run on Windows
dotnet run -f net8.0-windows10.0.19041

The Windows target can use either the Skia renderer or native WinAppSDK/WinUI 3 rendering.

Debugging

• Visual Studio: Full debugging with XAML Hot Reload, Live Visual Tree, Live Property Explorer
• WinUI diagnostics: Built-in diagnostic overlay for layout inspection

Packaging/Distribution

# Package as MSIX
dotnet publish -f net8.0-windows10.0.19041 -c Release \
  /p:PackageOutputPath=./packages

Distribution: Microsoft Store (MSIX), sideloading (MSIX with certificate), ClickOnce, or direct EXE.

Platform Gotchas

• WinAppSDK version alignment: The Windows TFM version must match the minimum Windows version. 10.0.19041 = Windows 10 2004+
• UAC and elevation: Apps cannot self-elevate. Design for standard user permissions
• Windows-specific APIs: Windows.Storage, Windows.Networking APIs are available only on Windows target. Use conditional compilation or Uno abstractions
• MSIX signing: MSIX packages must be signed for installation. Use a code signing certificate for distribution

AOT/Trimming

<PropertyGroup Condition="$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)')) == 'windows'">
  <PublishTrimmed>true</PublishTrimmed>
  <PublishAot>true</PublishAot>
</PropertyGroup>

Windows supports both JIT and AOT. AOT produces a single native EXE with faster startup.

Behavior Differences

• Navigation: Standard Windows navigation (Alt+Left for back, title bar back button)
• Authentication: Uses system browser or WAM (Web Account Manager) for SSO with Microsoft accounts
• Debugging: Richest debugging experience with Visual Studio Live Visual Tree and XAML Hot Reload

Linux (Skia/GTK)

Project Setup

# Build for Linux desktop
dotnet build -f net8.0-desktop

# Run on Linux
dotnet run -f net8.0-desktop

The Linux target uses the Skia renderer with a GTK host window. All XAML rendering is done by Skia -- GTK provides only the window and input handling.

Debugging

• VS Code with C# Dev Kit: Remote debugging on Linux
• JetBrains Rider: Full Linux debugging support
• Console logging: dotnet run outputs logs to terminal

Packaging/Distribution

# Publish self-contained for Linux
dotnet publish -f net8.0-desktop -c Release \
  --self-contained \
  -r linux-x64

# Package as AppImage, Flatpak, or Snap

Distribution: AppImage (portable, no install), Flatpak (sandboxed), Snap (Ubuntu Store), DEB/RPM packages.

Platform Gotchas

• GTK dependencies: The app requires GTK3 libraries at runtime. Package or document the dependency: libgtk-3-0, libskia*
• Skia rendering: All rendering is Skia-based. Native GTK widgets are not used. This ensures pixel-perfect cross-platform rendering but means the app does not follow the host GTK theme
• Font rendering: Ensure fonts are available on the target system. Embed fonts in the app or declare font dependencies
• Display scaling: HiDPI support works via Skia; test with GDK_SCALE=2 environment variable

AOT/Trimming

<PropertyGroup Condition="'$(TargetFramework)' == 'net8.0-desktop'">
  <PublishTrimmed>true</PublishTrimmed>
  <PublishAot>true</PublishAot>
</PropertyGroup>

AOT on Linux produces a native binary. Self-contained deployment avoids requiring a system-wide .NET runtime.

Behavior Differences

• Navigation: Keyboard-driven (Alt+Left for back). No gesture-based navigation
• Authentication: Uses system browser for OAuth flows. No platform-specific auth APIs
• Debugging: Standard .NET debugging. No platform-specific debugger tools

Embedded (Skia/Framebuffer)

Project Setup

The Embedded target uses the Skia renderer with a framebuffer backend, enabling headless or kiosk-style rendering without a windowing system.

# Build for embedded (same TFM as desktop)
dotnet build -f net8.0-desktop -r linux-arm64

# Run directly on embedded device
dotnet run -f net8.0-desktop

The embedded target shares the net8.0-desktop TFM with Linux desktop. Platform-specific configuration selects the framebuffer backend.

// Program.cs -- framebuffer host configuration
public static void Main(string[] args)
{
    SkiaHostBuilder.Create()
        .UseFrameBuffer()  // Use framebuffer instead of GTK
        .App(() => new App())
        .Build()
        .Run();
}

Debugging

• SSH remote debugging: Use VS Code Remote or dotnet-trace for remote profiling
• Serial console: Redirect logs to serial output for headless debugging
• Remote logging: Configure Serilog with network sink for remote log aggregation

Packaging/Distribution

# Publish self-contained for ARM64
dotnet publish -f net8.0-desktop -c Release \
  --self-contained \
  -r linux-arm64

# Deploy binary directly to device filesystem
scp -r ./publish/* pi@device:/opt/myapp/

Direct deployment to device filesystem. No app store or package manager.

Platform Gotchas

• No windowing system: No X11/Wayland. The app renders directly to the Linux framebuffer (/dev/fb0)
• Input handling: Touch input via Linux input events (/dev/input/event*). No mouse cursor by default
• Limited resources: Embedded devices often have constrained RAM and CPU. Profile memory usage carefully
• No browser: OAuth flows that require a browser are not available. Use device-code flow or pre-provisioned tokens
• Display resolution: Must match the framebuffer resolution. Set via kernel boot parameters or fbset

AOT/Trimming

AOT is strongly recommended for embedded due to limited resources and startup time requirements.

<PropertyGroup Condition="'$(RuntimeIdentifier)' == 'linux-arm64'">
  <PublishTrimmed>true</PublishTrimmed>
  <PublishAot>true</PublishAot>
  <InvariantGlobalization>true</InvariantGlobalization>
</PropertyGroup>

InvariantGlobalization reduces binary size by removing ICU data (~28MB). Only use if the app does not need locale-specific formatting.

Behavior Differences

• Navigation: Touch or hardware button only. No keyboard shortcuts or gesture bars
• Authentication: Device-code flow or pre-provisioned credentials. No browser-based OAuth
• Debugging: Remote only. No local IDE. Use SSH debugging or remote logging

Cross-Target Behavior Differences

Navigation

Authentication

Debugging Tools

Agent Gotchas

1. Do not hardcode TFM versions in detection logic. Use version-agnostic globs (net*-ios, net*-android) to handle both .NET 8 and future .NET versions.
2. Do not assume all targets share the same debugging workflow. iOS requires provisioning; Android requires ADB; WASM uses browser DevTools. Each target has distinct tooling.
3. Do not use JIT-dependent patterns on iOS. iOS prohibits JIT compilation. Code that uses Reflection.Emit, Expression.Compile(), or dynamic assembly loading will fail at runtime.
4. Do not forget platform-specific permissions. Android runtime permissions, iOS entitlements, macOS sandbox permissions, and WASM CORS policy are all different and must be handled per-target.
5. Do not deploy untrimmed WASM apps. Untrimmed WASM bundles exceed 30MB. Always enable trimming and consider AOT for production WASM deployments.
6. Do not assume file system access on all targets. WASM has no filesystem; iOS/macOS have sandbox restrictions; embedded may have read-only storage. Use Uno Storage abstractions.
7. Do not use the same authentication flow for all targets. WASM uses browser redirects, mobile uses native auth sessions, embedded uses device-code flow. Auth must be configured per-target.

Prerequisites

• .NET 8.0+ with platform workloads: dotnet workload install ios android maccatalyst wasm-tools
• Platform SDKs: Xcode (iOS/macOS), Android SDK (Android), GTK3 (Linux)
• Uno Platform 5.x+

References

• Uno Platform Getting Started
• Uno Platform Targets
• WASM Deployment
• iOS Deployment
• Android Deployment
• Linux with Skia/GTK