+------------------------------------------------------------------+
|                        TAURI APPLICATION                         |
+------------------------------------------------------------------+
|                                                                  |
|  +---------------------------+    +---------------------------+  |
|  |      FRONTEND (Shell)     |    |     BACKEND (Core)        |  |
|  |---------------------------|    |---------------------------|  |
|  |                           |    |                           |  |
|  |  HTML / CSS / JavaScript  |    |        Rust Code          |  |
|  |  (or any web framework)   |    |    (tauri crate + app)    |  |
|  |                           |    |                           |  |
|  |  - React, Vue, Svelte,    |    |  - System access          |  |
|  |    Solid, etc.            |    |  - File operations        |  |
|  |  - Standard web APIs      |    |  - Native features        |  |
|  |  - Tauri JS API           |    |  - Plugin system          |  |
|  |                           |    |                           |  |
|  +-------------+-------------+    +-------------+-------------+  |
|                |                                |                 |
|                |       IPC (Message Passing)    |                 |
|                +<------------------------------->+                |
|                |     Commands & Events          |                 |
|                                                                  |
|  +------------------------------------------------------------+  |
|  |                    WEBVIEW (TAO + WRY)                     |  |
|  |------------------------------------------------------------|  |
|  |  - Platform-native webview (not bundled)                   |  |
|  |  - Windows: WebView2 (Edge/Chromium)                       |  |
|  |  - macOS: WKWebView (Safari/WebKit)                        |  |
|  |  - Linux: WebKitGTK                                        |  |
|  +------------------------------------------------------------+  |
|                                                                  |
+------------------------------------------------------------------+
                                |
                                v
+------------------------------------------------------------------+
|                     OPERATING SYSTEM                             |
|  - Windows, macOS, Linux, iOS, Android                          |
+------------------------------------------------------------------+

Core vs Shell Design

Tauri follows a Core-Shell architecture where the application is split into two distinct layers:

The Core (Rust Backend)

The Core is the Rust-based backend that handles all system-level operations:

System access: File system, network, processes
Native features: Notifications, dialogs, clipboard
Security enforcement: Permission validation, capability checking
Plugin management: Extending functionality through plugins
App lifecycle: Window management, updates, configuration

The Core NEVER exposes direct system access to the frontend. All interactions go through validated IPC channels.

The Shell (Frontend)

The Shell is the user interface layer rendered in a webview:

Web technologies: HTML, CSS, JavaScript/TypeScript
Framework agnostic: Works with React, Vue, Svelte, Solid, or vanilla JS
Sandboxed execution: Runs in the webview's security sandbox
Tauri API access: Calls backend through @tauri-apps/api

Key Ecosystem Components

tauri Crate

The central orchestrator that:

Reads tauri.conf.json at compile time
Manages script injection into the webview
Hosts the system interaction API
Handles application updates
Integrates runtimes, macros, and utilities

tauri-runtime

The glue layer between Tauri and lower-level webview libraries. Abstracts platform-specific webview interactions so the rest of Tauri can remain platform-agnostic.

tauri-macros and tauri-codegen

Generate compile-time code for:

Command handlers (#[tauri::command])
Context and configuration parsing
Asset embedding and compression

TAO (Window Management)

Cross-platform window creation library (forked from Winit):

Creates and manages application windows
Handles menu bars and system trays
Supports Windows, macOS, Linux, iOS, Android

WRY (WebView Rendering)

Cross-platform WebView rendering library:

Abstracts webview implementations per platform
Handles webview-to-native communication
Manages JavaScript evaluation and event bridging

Webview Integration

Tauri uses the operating system's native webview rather than bundling a browser engine:

+-------------------+---------------------------+
|     Platform      |        WebView Engine     |
+-------------------+---------------------------+
| Windows           | WebView2 (Edge/Chromium)  |
| macOS             | WKWebView (Safari/WebKit) |
| Linux             | WebKitGTK                 |
| iOS               | WKWebView                 |
| Android           | Android WebView           |
+-------------------+---------------------------+

Benefits of Native WebViews

Smaller binary size: No bundled browser engine (~600KB vs ~150MB)
Security: OS vendors patch webview vulnerabilities faster than app developers can rebuild
Performance: Native integration with the operating system
Consistency: Users see familiar rendering behavior

Considerations

Slight rendering differences between platforms
Feature availability depends on OS webview version
Testing should cover all target platforms

Inter-Process Communication (IPC)

Tauri implements Asynchronous Message Passing for communication between frontend and backend. This is safer than shared memory because the Core can reject malicious requests.

IPC Flow Diagram

+------------------+                      +------------------+
|    Frontend      |                      |   Rust Backend   |
|   (JavaScript)   |                      |     (Core)       |
+--------+---------+                      +--------+---------+
         |                                         |
         |  1. invoke('command', {args})           |
         +---------------------------------------->|
         |                                         |
         |     [Request serialized as JSON-RPC]    |
         |                                         |
         |                    2. Validate request  |
         |                    3. Check permissions |
         |                    4. Execute command   |
         |                                         |
         |  5. Return Result<T, E>                 |
         |<----------------------------------------+
         |                                         |
         |     [Response serialized as JSON]       |
         |                                         |

Two IPC Primitives

Commands (Request-Response)

Type-safe, frontend-to-backend function calls:

// Rust backend
#[tauri::command]
fn greet(name: String) -> String {
    format!("Hello, {}!", name)
}

// Register in builder
tauri::Builder::default()
    .invoke_handler(tauri::generate_handler![greet])

// JavaScript frontend
import { invoke } from '@tauri-apps/api/core';

const greeting = await invoke('greet', { name: 'World' });
console.log(greeting); // "Hello, World!"

Key characteristics:

Built on JSON-RPC protocol
All arguments must be JSON-serializable
Returns a Promise that resolves with the result
Supports async Rust functions
Can access app state, window handle, etc.

Events (Fire-and-Forget)

Bidirectional, asynchronous notifications:

// Frontend: emit event
import { emit } from '@tauri-apps/api/event';
emit('user-action', { action: 'clicked' });

// Frontend: listen for events
import { listen } from '@tauri-apps/api/event';
const unlisten = await listen('download-progress', (event) => {
    console.log(event.payload);
});

// Backend: listen for events
use tauri::Listener;

app.listen("user-action", |event| {
    println!("User action: {}", event.payload());
});

// Backend: emit events
app.emit("download-progress", 50)?;

Key characteristics:

No return value (one-way)
Both frontend and backend can emit/listen
Best for lifecycle events and state changes
Not type-checked at compile time

Security Model Overview

Tauri implements multiple layers of security to protect both the application and the user's system.

Trust Boundary Model

+------------------------------------------------------------------+
|                     UNTRUSTED ZONE                               |
|  +------------------------------------------------------------+  |
|  |                    WebView Frontend                        |  |
|  |  - JavaScript code (potentially from remote sources)       |  |
|  |  - User input                                              |  |
|  |  - Third-party libraries                                   |  |
|  +------------------------------------------------------------+  |
+------------------------------------------------------------------+
                              |
                    [TRUST BOUNDARY]
                    [IPC Layer validates all requests]
                              |
+------------------------------------------------------------------+
|                      TRUSTED ZONE                                |
|  +------------------------------------------------------------+  |
|  |                    Rust Backend                            |  |
|  |  - Your Rust code                                          |  |
|  |  - Tauri core                                              |  |
|  |  - System access (gated by permissions)                    |  |
|  +------------------------------------------------------------+  |
+------------------------------------------------------------------+

Security Layers

WebView Sandboxing: Frontend code runs in the webview's security sandbox
IPC Validation: All messages crossing the trust boundary are validated
Capabilities: Define which permissions each window can access
Permissions: Fine-grained control over what operations are allowed
Scopes: Restrict command behavior (e.g., limit file access to specific directories)
CSP: Content Security Policy restricts what frontend code can do

Capabilities System

Capabilities control which permissions are granted to specific windows:

{
  "$schema": "../gen/schemas/desktop-schema.json",
  "identifier": "main-window-capability",
  "description": "Permissions for the main application window",
  "windows": ["main"],
  "permissions": [
    "core:path:default",
    "core:window:allow-set-title",
    "fs:read-files",
    "fs:scope-app-data"
  ]
}

Capabilities are defined in src-tauri/capabilities/ as JSON or TOML files.

Permission Structure

Capability
    |
    +-- windows: ["main", "settings"]  // Which windows
    |
    +-- permissions:                    // What's allowed
            |
            +-- "plugin:action"         // Allow specific action
            +-- "plugin:scope-xxx"      // Scope restrictions

Default Security Posture

Deny by default: Commands must be explicitly permitted
No remote access: Only bundled code can access Tauri APIs by default
Window isolation: Each window has its own capability set
Compile-time checks: Many security configurations are validated at build time

Rust Backend Structure

A typical Tauri backend follows this structure:

src-tauri/
+-- Cargo.toml              # Rust dependencies
+-- tauri.conf.json         # Tauri configuration
+-- capabilities/           # Permission definitions
|   +-- main.json
+-- src/
    +-- main.rs             # Entry point (desktop)
    +-- lib.rs              # Core app logic
    +-- commands/           # Command modules
    |   +-- mod.rs
    |   +-- file_ops.rs
    +-- state.rs            # App state management

Entry Point Pattern

// src-tauri/src/lib.rs
mod commands;

#[cfg_attr(mobile, tauri::mobile_entry_point)]
pub fn run() {
    tauri::Builder::default()
        .plugin(tauri_plugin_shell::init())
        .invoke_handler(tauri::generate_handler![
            commands::greet,
            commands::read_file,
        ])
        .manage(AppState::default())
        .run(tauri::generate_context!())
        .expect("error while running tauri application");
}

Command Patterns

// Basic command
#[tauri::command]
fn simple_command() -> String {
    "Hello".into()
}

// With arguments (camelCase from JS, snake_case in Rust)
#[tauri::command]
fn with_args(user_name: String, age: u32) -> String {
    format!("{} is {} years old", user_name, age)
}

// With error handling
#[tauri::command]
fn fallible() -> Result<String, String> {
    Ok("Success".into())
}

// Async command
#[tauri::command]
async fn async_command() -> Result<String, String> {
    tokio::time::sleep(Duration::from_secs(1)).await;
    Ok("Done".into())
}

// Accessing app state
#[tauri::command]
fn with_state(state: tauri::State<'_, AppState>) -> String {
    state.get_value()
}

// Accessing window
#[tauri::command]
fn with_window(window: tauri::WebviewWindow) -> String {
    window.label().to_string()
}

No Runtime Bundled

Tauri does NOT ship a runtime. The final binary:

Compiles Rust code directly into native machine code
Embeds frontend assets in the binary
Uses the system's native webview
Results in small, fast executables

This makes reverse engineering Tauri apps non-trivial compared to Electron apps with bundled JavaScript.

Summary

Component	Role
Core (Rust)	System access, security, business logic
Shell (Frontend)	UI rendering, user interaction
WebView (TAO+WRY)	Platform-native rendering bridge
IPC (Commands/Events)	Safe message passing between layers
Capabilities	Permission control per window

The architecture prioritizes:

Security: Multiple layers of protection, trust boundaries
Performance: Native code, no bundled runtime
Size: Minimal binary footprint
Flexibility: Any frontend framework, powerful Rust backend

understanding-tauri-architecture

Tauri Architecture

Architecture Overview