Electrobun

Electrobun is a TypeScript-first desktop app framework using Bun (runtime + bundler) and the system's native webview. Build apps that are ~14MB, with updates ~14KB, and startup <50ms.

Quick Start

Initialize New Project

bunx electrobun init          # Interactive scaffold
bun run dev                   # Development mode
bun run build                 # Production bundle

Choose from templates:

• hello-world: Minimal starter
• react-tailwind-vite: React + Tailwind + Vite
• svelte: Svelte framework
• photo-booth: Camera access example
• multitab-browser: Tab-based browser example

Project Structure

my-app/
├── electrobun.config.ts      # Build configuration
├── src/
│   ├── bun/
│   │   └── main.ts           # Main process (Bun)
│   └── views/
│       └── mainview/
│           ├── index.html
│           └── index.ts      # Webview frontend
└── package.json

Core Concepts

Main Process vs Webview

• Main Process (src/bun/main.ts): Runs in Bun, has full system access, manages windows, handles RPC
• Webview Process (src/views/*/index.ts): Runs in OS webview, sandboxed, handles UI, calls RPC

BrowserWindow

Create and manage application windows.

import { BrowserWindow } from "electrobun/bun";

const win = new BrowserWindow({
  title: "My App",
  url: "views://mainview/index.html",
  width: 1200,
  height: 800,
  frame: true,  // Standard window frame
  styleMask: ["titled", "closable", "miniaturizable", "resizable"],
});

Key Options:

• title: Window title
• url: Load URL (use views:// protocol for bundled views)
• width, height: Window dimensions
• x, y: Window position (optional)
• frame: Show standard window frame (true/false)
• styleMask: Array of window controls (macOS)
• titleBarStyle: "default" | "hidden" | "hiddenInset"
• trafficLightPosition: Custom position for macOS traffic lights

Methods:

win.loadURL("views://otherview/index.html")
win.setTitle("New Title")
win.resize({ width: 1024, height: 768 })
win.move({ x: 100, y: 100 })
win.show() / win.hide()
win.close()
win.focus()
win.minimize() / win.maximize() / win.fullscreen()

RPC: Main ↔ Webview Communication

Electrobun's killer feature — typed, fast, bidirectional RPC.

Main Process (bun/main.ts):

import { BrowserWindow } from "electrobun/bun";

const win = new BrowserWindow({ /* ... */ });

// Define what main exposes TO the webview
win.defineRpc({
  handlers: {
    async getUser(id: string) {
      // Full system access here
      const user = await db.getUser(id);
      return { name: user.name, id: user.id };
    },
    async saveFile(path: string, content: string) {
      await Bun.write(path, content);
      return { success: true };
    }
  }
});

// Call webview methods FROM main
const result = await win.rpc.updateUI({ data: "new data" });

Webview (views/mainview/index.ts):

import { Electroview } from "electrobun/browser";

const electroview = new Electroview();

// Call main process functions
const user = await electroview.rpc.getUser("123");
const result = await electroview.rpc.saveFile("/path/to/file.txt", "content");

// Define handlers main can call
electroview.defineRpc({
  handlers: {
    async updateUI(data: any) {
      // Update DOM here
      document.getElementById("content").textContent = data.data;
      return { updated: true };
    }
  }
});

Key Points:

• Fully type-safe (with TypeScript)
• Bidirectional (main can call webview, webview can call main)
• Async by default
• Serialize data automatically (JSON)

Application Menu

import { ApplicationMenu } from "electrobun/bun";

ApplicationMenu.setMenu([
  {
    label: "File",
    submenu: [
      { 
        label: "New Window", 
        accelerator: "CmdOrCtrl+N",
        action: () => createWindow()
      },
      { type: "separator" },
      { 
        label: "Quit", 
        accelerator: "CmdOrCtrl+Q",
        action: () => process.exit(0)
      },
    ]
  },
  {
    label: "Edit",
    submenu: [
      { role: "undo" },
      { role: "redo" },
      { type: "separator" },
      { role: "cut" },
      { role: "copy" },
      { role: "paste" },
    ]
  }
]);

Built-in roles: undo, redo, cut, copy, paste, selectAll, minimize, close, quit

Context Menu

import { ContextMenu } from "electrobun/bun";

win.on("context-menu", (event) => {
  ContextMenu.show([
    { label: "Copy", action: () => { /* copy logic */ } },
    { type: "separator" },
    { label: "Paste", action: () => { /* paste logic */ } },
  ]);
});

System Tray

import { Tray } from "electrobun/bun";

const tray = new Tray({
  icon: "assets://tray-icon.png",
  tooltip: "My App",
  menu: [
    { label: "Show", action: () => win.show() },
    { label: "Hide", action: () => win.hide() },
    { type: "separator" },
    { label: "Quit", action: () => process.exit(0) },
  ]
});

// Update icon dynamically
tray.setIcon("assets://tray-icon-active.png");

Auto Updater

import { Updater } from "electrobun/bun";

const updater = new Updater({
  url: "https://updates.myapp.com/latest.json",
  autoCheck: true,
  interval: 60 * 60 * 1000, // Check every hour
});

updater.on("update-available", async (info) => {
  console.log("Update available:", info.version);
  // Show dialog, then:
  updater.downloadAndInstall();
});

updater.on("update-downloaded", () => {
  console.log("Update ready, restart to apply");
});

updater.on("error", (err) => {
  console.error("Updater error:", err);
});

Paths & Assets

import { paths } from "electrobun/bun";

// OS directories
paths.appData      // App data directory
paths.userData     // User-specific data
paths.resources    // Bundled resources
paths.home         // User home directory
paths.temp         // Temporary directory

// Reference bundled assets:
// views://viewname/file.html  → views folder
// assets://file.png           → assets folder

Example: Persistent State

import { join } from "path";

const stateFile = join(paths.userData, "state.json");

// Read
const state = JSON.parse(await Bun.file(stateFile).text() || "{}");

// Write
await Bun.write(stateFile, JSON.stringify(state));

Window Events

win.on("close", () => {
  console.log("Window closing");
});

win.on("resize", ({ width, height }) => {
  console.log("Window resized:", width, height);
});

win.on("move", ({ x, y }) => {
  console.log("Window moved:", x, y);
});

win.on("focus", () => console.log("Window focused"));
win.on("blur", () => console.log("Window blurred"));

App Lifecycle Events

import { app } from "electrobun/bun";

app.on("ready", () => {
  console.log("App ready, create windows");
});

app.on("before-quit", () => {
  console.log("App about to quit, cleanup");
});

app.on("window-all-closed", () => {
  if (process.platform !== "darwin") {
    app.quit();
  }
});

Build Configuration

electrobun.config.ts:

import { defineConfig } from "electrobun";

export default defineConfig({
  app: {
    name: "My App",
    version: "1.0.0",
    identifier: "com.example.myapp",
  },
  build: {
    main: "src/bun/main.ts",
    views: {
      mainview: "src/views/mainview/index.ts",
      settings: "src/views/settings/index.ts",
    },
  },
  icons: {
    mac: "assets/icon.icns",
    win: "assets/icon.ico",
    linux: "assets/icon.png",
  },
  updates: {
    provider: "generic",
    url: "https://updates.myapp.com",
  },
});

Common Patterns

Multiple Windows

const windows = new Map<string, BrowserWindow>();

function createWindow(id: string, url: string) {
  const win = new BrowserWindow({
    url,
    width: 800,
    height: 600,
  });
  
  windows.set(id, win);
  
  win.on("close", () => {
    windows.delete(id);
  });
  
  return win;
}

Opening External Links

import { shell } from "electrobun/bun";

// In main process
shell.openExternal("https://example.com");

// In webview, intercept link clicks
document.addEventListener("click", (e) => {
  const link = (e.target as HTMLElement).closest("a");
  if (link && link.href.startsWith("http")) {
    e.preventDefault();
    electroview.rpc.openExternal(link.href);
  }
});

Draggable Title Bar

<!-- In webview HTML -->
<div style="-webkit-app-region: drag; height: 40px; background: #333;">
  <h1 style="-webkit-app-region: no-drag;">My App</h1>
  <button style="-webkit-app-region: no-drag;">Click Me</button>
</div>

File Dialogs

import { dialog } from "electrobun/bun";

// Open file
const result = await dialog.showOpenDialog({
  title: "Select File",
  filters: [
    { name: "Images", extensions: ["png", "jpg", "jpeg"] },
    { name: "All Files", extensions: ["*"] }
  ],
  properties: ["openFile", "multiSelections"]
});

if (!result.canceled) {
  console.log("Selected files:", result.filePaths);
}

// Save file
const saveResult = await dialog.showSaveDialog({
  title: "Save File",
  defaultPath: "untitled.txt",
  filters: [
    { name: "Text Files", extensions: ["txt"] },
  ]
});

Platform Notes

macOS

• Uses WKWebView
• Requires code signing for distribution
• Notarization required for Gatekeeper
• Install Xcode Command Line Tools for development

Windows

• Uses WebView2 (Edge)
• Requires Visual Studio Build Tools for development
• Code signing recommended for SmartScreen

Linux

• Uses WebKit2GTK
• Install development packages:

  sudo apt install libgtk-3-dev libwebkit2gtk-4.1-dev
  

Next Steps

• Advanced window management: See electrobun-window-management skill for multi-window apps and BrowserView
• RPC patterns: See electrobun-rpc-patterns skill for type safety and performance
• Native UI: See electrobun-native-ui skill for menus, trays, and dialogs
• Distribution: See electrobun-distribution skill for packaging and updates
• Debugging: See electrobun-debugging skill for troubleshooting

Resources

• Documentation: https://blackboard.sh/electrobun/
• GitHub: https://github.com/blackboardsh/electrobun
• Discord: https://discord.gg/ueKE4tjaCE
• Examples: https://github.com/blackboardsh/electrobun/tree/main/templates