Building

The desktop app uses Tauri's build system to produce native installers for Windows, macOS, and Linux. The frontend is compiled with Vite, and the Rust backend is compiled to a native binary that embeds the frontend assets.

Development

Start the development environment with hot reload for both the frontend and Rust backend:

# From the repository root
npm run dev:desktop

# Or from the desktop directory
cd desktop
npm run tauri:dev

This runs two processes simultaneously:

1. Vite dev server on http://localhost:5173 -- serves the React frontend with HMR
2. Tauri dev window -- native window that loads from the Vite dev server, with Rust hot-reload on backend changes

The Vite dev server is started by Tauri automatically via the beforeDevCommand in tauri.conf.json.

Production Build

Build a distributable installer for the current platform:

# From the repository root
npm run build:desktop

# Or from the desktop directory
cd desktop
npm run tauri:build

The build process:

1. Runs npm run build (TypeScript compilation + Vite production build)
2. Bundles the frontend output from desktop/dist/ into the Rust binary
3. Compiles the Rust backend in release mode (LTO, size optimization, symbol stripping)
4. Packages the binary into platform-specific installers

Platform Outputs

Tauri produces different installer formats depending on the build platform:

Windows

Format	File	Description
NSIS	Relate Mail_0.1.0_x64-setup.exe	Standard Windows installer with install/uninstall wizard
MSI	Relate Mail_0.1.0_x64_en-US.msi	Windows Installer package for enterprise/GPO deployment

Both formats are built by default. The NSIS installer provides a familiar user experience, while MSI is preferred for managed enterprise environments.

macOS

Format	File	Description
DMG	Relate Mail_0.1.0_aarch64.dmg	Disk image with drag-to-Applications installation

The DMG is built for the host architecture (Apple Silicon or Intel). Cross-compilation is possible with additional Xcode toolchain configuration.

Linux

Format	File	Description
AppImage	relate-mail_0.1.0_amd64.AppImage	Portable, self-contained executable (no installation needed)
Deb	relate-mail_0.1.0_amd64.deb	Debian/Ubuntu package for APT installation

Build artifacts are written to desktop/src-tauri/target/release/bundle/.

Icons

Tauri requires icons in multiple formats to support all platforms. The icon files are located in desktop/src-tauri/icons/:

File	Usage
32x32.png	Windows taskbar, Linux panel
128x128.png	Standard app icon
128x128@2x.png	HiDPI/Retina displays
icon.icns	macOS application icon
icon.ico	Windows application icon

To regenerate icons from a source image, use the Tauri CLI:

cd desktop
npx tauri icon path/to/source-1024x1024.png

Tauri Configuration

The build is configured in desktop/src-tauri/tauri.conf.json:

{
  "productName": "Relate Mail",
  "identifier": "com.relate.mail.desktop",
  "version": "0.1.0",
  "build": {
    "beforeDevCommand": "npm run dev",
    "devUrl": "http://localhost:5173",
    "beforeBuildCommand": "npm run build",
    "frontendDist": "../dist"
  },
  "bundle": {
    "active": true,
    "targets": "all"
  }
}

Key settings:

• frontendDist -- Path to the Vite build output, relative to src-tauri/
• targets: "all" -- Builds all available installer formats for the current platform
• bundle.active: true -- Enables the bundling step (set to false to produce only the binary without installers)

Release Build Optimizations

The Rust release profile in Cargo.toml is configured for minimal binary size:

Setting	Value	Effect
codegen-units	1	Single compilation unit enables maximum optimization
lto	true	Link-time optimization across all crates
opt-level	"s"	Optimize for binary size over speed
panic	"abort"	Remove panic unwinding code
strip	true	Strip debug symbols from the binary

These settings increase build time but produce a significantly smaller distributable.

Code Signing

Platform-specific code signing is required for distribution:

Windows

Configure via tauri.conf.json under bundle.windows:

{
  "certificateThumbprint": "YOUR_CERT_THUMBPRINT",
  "digestAlgorithm": "sha256",
  "timestampUrl": "http://timestamp.digicert.com"
}

Or via environment variables:

• TAURI_SIGNING_PRIVATE_KEY -- The private key for signing
• TAURI_SIGNING_PRIVATE_KEY_PASSWORD -- The key password

macOS

Set the following environment variables:

• APPLE_CERTIFICATE -- Base64-encoded .p12 certificate
• APPLE_CERTIFICATE_PASSWORD -- Certificate password
• APPLE_SIGNING_IDENTITY -- Developer ID Application identity
• APPLE_ID -- Apple ID for notarization
• APPLE_PASSWORD -- App-specific password for notarization
• APPLE_TEAM_ID -- Apple Developer team ID

Linux

Linux packages are typically not code-signed. For distribution via package repositories, GPG signing of the .deb package is recommended.

CI/CD

The desktop-build.yml GitHub Actions workflow automates cross-platform builds:

1. Trigger -- Runs on push to main and on tags
2. Matrix -- Builds on windows-latest, macos-latest, and ubuntu-latest runners
3. Steps -- Install dependencies, build frontend, build Tauri, upload artifacts
4. Artifacts -- Installers for all platforms are uploaded as workflow artifacts and attached to GitHub Releases on tag pushes

The workflow installs platform-specific prerequisites (e.g., libwebkit2gtk-4.1-dev on Linux) before building.