D&D Beyond Sync

Keeps spectators in sync with the DM’s map view on D&D Beyond by mirroring pan and zoom between tabs in the same game.

• Leader (DM): Broadcasts pointer drag (pan), wheel (zoom), and HUD zoom button clicks.
• Spectator (viewer): Blocks local pan/zoom, hides toolbar, listens to the leader, and replays events.

Installation

1. Download the source files
   Clone this repo or download the files (manifest.json and content.js) into a single folder.

2. Open Chrome Extensions
   In Chrome, go to: chrome://extensions/

3. Enable Developer Mode
   Toggle Developer mode in the top-right corner.

4. Load the extension
   Click Load unpacked and select the folder containing the files.

5. The extension should now appear in your Chrome extensions list.

Usage

• Leader (DM):
  Open a D&D Beyond game as the DM. A blue badge labeled “Leader” will appear in the bottom-left corner of the screen.

• Spectator:
  In the same game, click the Spectator View button in the D&D Beyond toolbar. The spectator window will display a green badge labeled “Spectator” in the bottom-left corner.

• Sync in Action:
  As the Leader pans or zooms the map, all Spectators automatically follow along in real time — with no local control required.

Notes

• Works only on pages matching https://www.dndbeyond.com/games/*.
• Requires Chrome or a Chromium-based browser with support for BroadcastChannel (most modern versions).

Reporting Issues

If you find a bug or have a feature request, please open an issue on this repository.

When reporting an issue, please include:

• A short description of the problem
• Steps to reproduce it
• Any error messages from the browser console (press F12 → Console tab)

This will help me debug and improve the extension quickly.

Credits

Created by Nicolai D. Madsen (@nicodm13), 2025.