TypeCast — Keystroke visualizer for screen recording#

TypeCast is a lightweight, cross‑platform desktop overlay that shows your keystrokes while you record or present. Built with Tauri (Rust + React), it stays always‑on‑top, is click‑through, and appears on all workspaces without getting in your way.

Demo#

Minimal overlay showing recent keys with modifier caps

Features#

• System tray controls: Start Monitoring, Stop Monitoring, Quit
• Always on top and visible on all workspaces/virtual desktops
• Transparent, frameless, full‑screen click‑through window (doesn’t block clicks)
• Displays recent key presses (with modifiers like Ctrl, Alt, Shift, ⌘)
• Clean keycaps UI; shows combos (e.g., Ctrl + C) and arrows/glyphs (↑ ↓ ← →, ⏎, ⌫, etc.)
• Auto‑hide after inactivity (default 5s) and fades in on next key press
• Privacy‑friendly: no disk logging, no network access; events are ephemeral in memory
• Cross‑platform by design (Windows/macOS/Linux)

App icon: src-tauri/icons/icon.png

How it works#

• Global keystroke listener (Rust): src-tauri/src/setup/keystoke.rs
  • Uses the rdev crate to capture key press/release events and maintain modifier state
  • Emits events to the frontend via Tauri window events ("key-logger")
• Toggle monitoring (Rust): src-tauri/src/commands/monitoring.rs
  • start_monitoring / stop_monitoring flip an AtomicBool used by the listener
• System tray (Rust): src-tauri/src/setup/tray.rs
  • Tray menu items emit "start_monitoring" / "stop_monitoring" to the webview
• Overlay UI (React): src/App.tsx
  • Listens for "key-logger" events and renders the last 10 key events as keycaps
  • Auto‑hides after 5s of inactivity; re‑shows on the next key press

Window behavior (from src-tauri/tauri.conf.json):

• alwaysOnTop: true, visibleOnAllWorkspaces: true, transparent: true, decorations: false
• fullscreen: true, skipTaskbar: true, click‑through is enabled in setup via set_ignore_cursor_events(true)

Prerequisites#

• Rust (stable) + Cargo
• Node.js 18+ and pnpm
• Tauri OS dependencies (Linux/macOS/Windows)
  • Linux (Debian/Ubuntu) commonly needs: libwebkit2gtk-4.1-dev, libssl-dev, libgtk-3-dev, libayatana-appindicator3-dev, librsvg2-dev, build-essential
  • See official docs for your distro: https://v2.tauri.app/start/prerequisites/

Note (Linux/Wayland): global key capture may require X11 (Xorg or XWayland). Pure Wayland sessions are limited.

Develop#

pnpm install
pnpm tauri dev

This runs the React dev server (Vite) and launches the Tauri shell.

Build#

pnpm tauri build

Artifacts will be produced under src-tauri/target/release (bundles under bundle/).

Usage#

• Launch the app; a transparent, click‑through overlay is created
• Use the tray icon menu:
  • Start Monitoring — begin emitting keystrokes to the overlay
  • Stop Monitoring — pause the listener and clear modifier state
  • Quit App — exit cleanly
• Type normally; recent keys appear at the bottom‑right and fade out after 5s

macOS: You may be prompted to grant Accessibility permissions for global key capture. Windows: Some environments may require elevated permissions.

Configuration & tweaks#

• Overlay window options: src-tauri/tauri.conf.json
  • Always‑on‑top, transparency, visibility on all workspaces, etc.
• Click‑through behavior: enabled in src-tauri/src/setup/mod.rs via set_ignore_cursor_events(true)
• Auto‑hide timeout: src/App.tsx — setTimeout(() => setVisible(false), 5000)
• Key glyph mapping: src-tauri/src/setup/keystoke.rs (get_key_string) — adjust labels/icons
• Styles: src/App.css

Known limitations#

• Wayland capture support is limited; X11/XWayland works best today
• Some keyboards/IMEs may report keys as Unknown and won’t render a label
• No persistence: the tool is display‑only by design (no export history yet)

Tech stack#

• Tauri 2 (@tauri-apps/cli, @tauri-apps/api)
• Rust + rdev (global input capture)
• React 18, Vite 6, Tailwind CSS

Project layout#

• Frontend: src/ (entry src/main.tsx, UI src/App.tsx)
• Tauri app: src-tauri/ (entry src-tauri/src/main.rs, config tauri.conf.json)
• Tray & listener setup: src-tauri/src/setup/
• Commands (invokes): src-tauri/src/commands/
• Assets: assets/ (screenshots, demo)

Credits#

• Built with Tauri, React, and the rdev crate — thanks to their maintainers and communities.

If you find this useful, consider starring the repo and opening issues/PRs for ideas and improvements.