pitwall

Local Forza Horizon 6 telemetry overlay — an OBS Browser Sourceand a transparent, always-on-top desktop HUD (system tray + settings), with cinematic broadcast-style skins.

FH6 (UDP Data Out) ──► Node.js server ──► WebSocket ──► HTML widget (OBS Browser Source)

No build step, no framework — vanilla HTML/CSS/JS + a small Node.js server.

1. In-game setup

In Forza Horizon 6: SETTINGS → HUD AND GAMEPLAY → Data Out

• Data Out: ON
• Data Out IP Address: 127.0.0.1
• Data Out IP Port: 20777 (must match the UDP port — set in the overlay app's Connection settings, or UDP_PORT for the standalone server)

2. Start the server

Windows: double-click start.bat (installs dependencies and creates .env on first run).

Or manually:

cp .env.example .env # optional — defaults work out of the box
npm install
npm start

You should see the UDP port, HTTP port, and the Browser Source URL logged.

Dev mode with auto-restart: npm run dev.

3. OBS Browser Source

Add a Browser Source:

• URL: http://localhost:9000
• Width: 400, Height: 200
• Custom CSS: body { background-color: rgba(0,0,0,0); margin: 0; }

The overlay shows "WAITING…" until FH6 starts sending packets (i.e. you're in a race).

4. On-screen overlay app (without OBS) — system tray + settings window

A small Electron app shows the widgets directly on top of the game (no OBS), driven from a system-tray icon and a settings window with three tabs. It starts the telemetry server itself (in the background, no console), so you don't need start.bat; OBS keeps working in parallel on http://localhost:9000.

Run (portable — no install)

Double-click FH6-Overlay-1.0.0-portable.exe (build it with npm run dist — see Build). No setup, no shortcuts: it runs straight away and a tray icon appears; click it to open Settings. (To start it with Windows, tick Launch at Windows startup in Settings — keep the .exe in a fixed location, since a portable app is registered by its current path.)

Settings window

• In-game tab — check/uncheck each widget to show it on screen (Speed, Shift light, Lap delta, Vehicle, Tires, G-Force, Combined HUD). Plus: Show only when Forza is active (hide on alt-tab), Lock overlays (clicks pass through vs. drag-to-reposition), Hide all, Launch at Windows startup, Reset positions, and a Connection section — set the Listen IP, UDP port (match FH6 Data Out) and HTTP/WS port right in the app, no .env needed. Changing a port restarts the server and reloads the overlays.

• Appearance tab — a Preset theme (Classic · Cinematic · Neon · Carbon · WEC, via public/skin.css), plus accent/alert colour, background opacity, font, speed km/h ↔ mph, temp °C ↔ °F, and per-widget size, opacity, field show/hide and style:

  • Speed — Digital · Analog · Cinematic (gradient redline arc + glowing eased needle)
  • Tires — Grid · Car-corners · G-Force — Circle · Ball · Shift — Bar · Arc

  Everything previews live and applies to OBS too. (A custom font is fetched from Google Fonts, so it needs internet; the default Orbitron/monospace work offline.)

• OBS tab — the customized Browser-Source URL for each widget (your Appearance settings are baked in, so OBS looks identical) with Copy / Open buttons and the recommended size. Add these in OBS as Browser Sources.

Tray menu (right-click): Settings… · Show/Hide overlays · Quit. Shortcuts: Ctrl+Alt+L lock/unlock, Ctrl+Alt+H hide/show.

⚠️Borderless required: a transparent overlay only draws over FH6 if the game runs in Borderless / borderless windowed mode, not exclusive fullscreen (a Windows limitation; OBS is unaffected because it captures the source directly).

Preferences (enabled widgets, positions, appearance, gating, autostart) are saved in Electron's userData folder.

Run from source (no build)

setup.bat once, then double-click FH6-Overlay.vbs (silent, no console), or npm run overlay.

Build

npm install
npm run dist # → dist/FH6-Overlay-1.0.0-portable.exe (single portable .exe)
npm run pack # → dist/win-unpacked/ (unpacked folder, runnable without packing)

If npm run dist fails with “Cannot create symbolic link: A required privilege is not held”, electron-builder can't unpack its signing cache without symlink permission. Fix once by enabling Windows Developer Mode (Settings → Privacy & security → For developers), or run the build from an elevated terminal. The build is intentionally unsigned (personal tool), so signing is skipped. npm run pack doesn't need this.

Vehicle widget: shows the car name (from CarOrdinal), class, PI and drivetrain. The ordinal → name mapping comes from public/cars.json (community Forza-Horizon-Discord-Rich-Presence database, ~1300 entries). If a car is missing, the widget shows Car #<ordinal> — just add it to cars.json.

Foreground detection: a hidden PowerShell script (electron/foreground-watch.ps1) reads the active window via Win32 (GetForegroundWindow) and tells the overlay when Forza gains or loses focus. The watcher is started first at launch so detection is immediate; if it fails (PowerShell blocked) the overlay falls back to "always visible" rather than staying hidden.

Configuration

The overlay app configures these in its Connection settings (saved in userData, no .env). The values below are the env vars for the standalone server (npm start / start.bat); the app's settings override them.

Variable	Default	Description
UDP_HOST	127.0.0.1	Bind address (127.0.0.1 = loopback only; set 0.0.0.0 only if the game runs on a separate console/PC — that also exposes the port to the LAN)
HTTP_HOST	127.0.0.1	HTTP/WS bind (loopback; OBS still uses http://localhost)
UDP_PORT	20777	Must match FH6 Data Out IP Port setting
HTTP_PORT	9000	Browser Source URL: http://localhost:9000
LOG_LEVEL	info	Set to debug to print every parsed packet

Avoid UDP ports 5200–5300 — FH6 binds its own outgoing socket in that range.

Notes & limitations

• Firewall: Windows may block UDP 20777. Allow Node.js through Windows Defender Firewall if no data arrives.
• Single binder: only one app can bind a given UDP port. Close other FH6 telemetry tools first.
• Localhost-only; no authentication by design.

Verifying the parser

node src/parser.js

Runs an inline offset test against a hand-crafted 324-byte packet.

License

MIT © StealthyLabs. Not affiliated with or endorsed by Playground Games / Microsoft; Forza Horizon is a trademark of Microsoft. Car name data in public/cars.json comes from the community Forza-Horizon-Discord-Rich-Presence project.