This is an alpha. Compass Bridge is alpha and it writes to real things: your players' D&D Beyond sheets and your live Roll20 game, including tokens, bars, chat and the Turn Order. When you announce turns with the end-turn link on, it also adds an ability named EndTurn to each player's Roll20 character. It works by operating the same pages you use, so a layout change on D&D Beyond or Roll20 can break a feature until the extension is updated. It has not been through Chrome Web Store review yet: for now it installs from a download as an unpacked extension, and the Windows installer is not code-signed, so Windows may warn about an unknown publisher. Try it on a test campaign first.
About
Compass Bridge is a Chrome extension you install once. It sits between the DM Screen, D&D Beyond, Roll20 and, if you use it, the Loremaster's Compass desktop app, and it does what you would otherwise do by hand: read character sheets, read and set the Turn Order, put hit points on tokens, post lines to chat and write HP and conditions back onto a sheet. It works through pages you already have open and your own logins, so there is nothing to hand over. It is for the DM only; your players install nothing.
Requirements
Google Chrome on a computer. The installer is for Windows; the ZIP holds the same files if you would rather extract it yourself and use Load unpacked.
Developer mode switched on at chrome://extensions, because it is not on the Chrome Web Store yet.
The DM Screen open in a tab. The extension only talks to the DM Screen sites (production and staging) and to localhost, plus D&D Beyond and Roll20.
D&D Beyond: you signed in on dndbeyond.com in the same Chrome. It uses that session and never asks for your password.
Roll20: a game you run as GM, open in the same Chrome window with the Turn Order window visible. No Pro subscription and no Mod script are needed for the main features.
Optional: the Loremaster's Compass desktop app running on the same computer, for dice, creatures, character sync and saved preferences.
Get started
Open the Connector page on the DM Screen site and click Download Windows installer, or Download ZIP instead.
Run the installer, or extract the ZIP into the DM Screen Connector folder inside your Documents folder. If Windows warns about an unknown publisher, that is because the installer is not code-signed; the ZIP avoids running an executable.
In Chrome, open chrome://extensions and turn on Developer mode.
Choose Load unpacked and select the DM Screen Connector folder. Chrome shows the permissions it needs and you accept them.
Refresh any open D&D Beyond, Roll20 and DM Screen tabs so they pick up the extension.
On the DM Screen, the top bar should read Bridge followed by a version number. If it says Bridge offline, the extension is not being seen.
Open Sync health in the DM Screen sidebar and use Check open sheets, Check Turn Order and, if you use the Compass, Check dice relay to confirm each link.
To update later, run the new installer or replace the folder's files, click the circular Reload arrow on the extension's card at chrome://extensions, confirm the version, then refresh your open tabs.
Features
Reading D&D Beyond sheets Alpha
Reads HP, AC, initiative, abilities, saves, passives, movement, vision, coins, containers, equipped gear, attunement, conditions, tagged DM notes and each character's spellbook, either for your campaign or for the sheets you have open. The DM Screen asks for this when you click Sync D&D Beyond.
Watching sheets live Alpha
While a DM Screen is open it re-reads each of your campaign's sheets about every 30 seconds and reports changes to HP, temp HP, conditions, death saves and the like. This only reads, needs no sheet tab open, and stops three minutes after the last DM Screen closes.
Writing HP and conditions to a sheet Alpha
Writes HP, temp HP, the max HP modifier, conditions, exhaustion and death saves onto a character's sheet by using the sheet's own panes, then reads the character record back and only reports success if it matches. Edits are queued and written one sheet at a time.
Inventory, notes and homebrew items Alpha
On your request it adds, moves and removes items, moves coins, writes tagged notes into a sheet's Background journal, and creates, deletes or restores your own private magic items in the D&D Beyond homebrew builder. Each step is read back before the DM Screen counts it as done.
Roll20 Turn Order Alpha
Reads the Turn Order, writes initiative scores onto it and sorts it, adds the tokens you have selected, removes a duplicate turn for the same token, and pushes turn changes to the DM Screen as they happen so it follows even from a background tab.
Roll20 chat Alpha
Types lines into Roll20's own chat box: turn announcements, whispers to players, initiative rolls and effect lines. It also watches chat for a typed done, roll cards such as Beyond20 attack cards, and plain dice rolls, and passes only those to the DM Screen. A chat draft you are typing is never overwritten.
Roll20 tokens, bars, light and vision Alpha
Reads and sets token bars, the hover tooltip, status markers, names, aura rings, light and vision through Roll20's own game model, and reports a token dropped on the map or a bar a player edits. It also reads token positions and sizes so the DM Screen can tell who stands inside an area.
Spell templates and linked tokens Alpha
Places a spell's area on the map as a token sized from the page grid, keeps it behind the creatures so it never blocks a click, and feeds the DM Screen live movement so it can apply effects as people move. It also keeps linked tokens, such as a rider and a mount, moving together.
Monster catalogue and creature stat blocks Alpha
Reads monster names, types, CR, sources and links from your D&D Beyond account, including subscribed homebrew, for the encounter builder. It reads the traits and actions of creatures that live in your Roll20 journal for the DM Screen's stat block view, and can place a journal creature's token on the map and in the Turn Order.
Account spell lists Alpha
Reads the spell lists your D&D Beyond account can see, with area, save, damage and duration, so the DM Screen knows which spells can drive a template. Some prepared-caster lists come back incomplete from D&D Beyond, so the DM Screen also uses your party's own spellbooks.
Compass dice relay Alpha
With the Compass desktop app running on the same computer, dice text rolled there is posted into an open Roll20 chat, where Roll20 performs the roll itself. It only looks for the Compass while a Roll20 chat box is on screen and never touches your clipboard.
Compass creatures, characters and preferences Experimental
With the Compass running, it can write a Compass creature into your Roll20 journal as a character and place its token, keep characters in step between the Compass and the DM Screen, and keep the DM Screen's spell-template preferences in the Compass. The two-way character sync in particular has not had a full live test.
Tab and account safeguards Alpha
It expands a collapsed Chrome tab group while it reads a sheet in it, keeps sheet and Roll20 tabs from being discarded by Memory Saver, and opens temporary background tabs for some reads. If it positively sees a different D&D Beyond account than the one that supplied your saved data, it tells the DM Screen to clear that D&D Beyond-derived data.
How to
Install Compass Bridge for the first time
Open the Connector page on the DM Screen site and download the Windows installer or the ZIP.
Run the installer, or extract the ZIP into the DM Screen Connector folder inside your Documents folder.
Open chrome://extensions and switch on Developer mode.
Click Load unpacked and choose the DM Screen Connector folder.
Refresh your DM Screen, D&D Beyond and Roll20 tabs.
Check that the DM Screen's top bar reads Bridge and a version number.
Update it to a newer version
Download the latest installer or ZIP from the Connector page and run it, or extract it over the same DM Screen Connector folder.
Open chrome://extensions and click the circular Reload arrow on the extension's card.
Confirm the version on the card. If Chrome says the extension needs new permissions, re-enable it on the card.
Refresh every open D&D Beyond, Roll20 and DM Screen tab.
On the DM Screen, check that the top bar shows the new version.
Check that everything is connected
Open Sync health in the DM Screen sidebar.
Look at Connector: it should show the extension's version followed by responding.
Click Check open sheets with your D&D Beyond character tabs open and read how many it finds.
Click Check Turn Order with your Roll20 game open and the Turn Order window showing.
If you use the Compass, start it and click Check dice relay.
The four lamps in the top bar (Connector, Roll20, D&D Beyond, Compass) show the same thing at a glance; hover one for details.
Reconnect Roll20 after the extension has been updated or reloaded
Refresh the Roll20 tab. An open Roll20 tab stops reading chat when the extension reloads, and only a page refresh brings it back.
Keep the Turn Order window open in the refreshed game.
If the DM Screen says the Roll20 link is lost, click Import on Initiative to relink the game.
If the DM Screen still shows the warning that Roll20 has stopped listening to chat, refresh the Roll20 tab again.
Use it with the Compass desktop app
Start Loremaster's Compass on the same computer and switch it to the campaign you are running.
Open your Roll20 game and keep its chat box on screen.
On the DM Screen, open Sync health and click Check dice relay.
Roll in the Compass. The dice text appears in Roll20 chat and Roll20 rolls it.
Turn it off or remove it
Open chrome://extensions.
Switch the extension's toggle off to pause it, or choose Remove to uninstall it.
Its access to D&D Beyond, Roll20 and the DM Screen pages ends straight away.
The DM Screen will show Bridge offline until you switch it back on or reinstall it.
Known limits
It is not on the Chrome Web Store yet. You install it unpacked with Developer mode on, and the Windows installer is not code-signed.
It is built for Chrome only. No other browser is covered.
It operates the D&D Beyond and Roll20 pages the way you would, so a layout change on either site can break a feature until the extension is updated. This has happened before, for example when D&D Beyond turned the campaign link on a sheet into a button.
Roll20 features need the game open as GM in the same Chrome window with the Turn Order window visible. If several games are open the DM Screen links only one of them.
After the extension reloads, already-open Roll20, D&D Beyond and DM Screen tabs need a refresh. A Roll20 tab that has not been refreshed stops reading chat without any other sign, and the DM Screen shows a banner telling you to refresh it.
Live reads of your sheets run about every 30 seconds, and writes to a sheet are made one sheet at a time through the sheet's own controls, so they are not instant. If a scan sits on Still reloading, click that sheet's tab once so it loads.
The Roll20 selected-token roll, exact timers and synchronized deletion need a separate Initiative Mod in a Pro game and have never been tested at a live table.
The Compass link uses the Compass's local ports 21356 to 21358. Do not run the older standalone Loremaster's Compass Roll20 Bridge extension at the same time, because both would post the same rolls.
Questions
The DM Screen says Bridge offline though I installed it. Why?
The usual causes are that the extension is disabled on chrome://extensions, or the DM Screen tab was open before you installed it and needs a refresh. After an update Chrome may also hold the extension until you re-enable its new permissions on its card. The extension only runs on the DM Screen sites and localhost, so a copy of the page on any other address will not see it.
A DM Screen button is greyed out or missing. Why?
The DM Screen only offers a feature when the connector says it supports it. An older connector lacks newer features, so the control stays off. Update the extension and refresh the tabs. Roll20 features are also greyed until you have linked a game with Import.
Import says no Roll20 game is open, or that the Turn Order is not visible.
Open your game as GM in the same Chrome window, then open the Turn Order window from the toolbar icon in Roll20 and click Import again. If more than one game is open, close the extra ones.
A change I made on D&D Beyond has not shown up yet.
The extension re-reads your campaign's sheets about every 30 seconds while a DM Screen is open, so there is a short delay. It stops reading three minutes after the last DM Screen closes, and you need to be signed in to D&D Beyond in the same Chrome.
Why did Chrome open a tab I did not ask for?
For some reads, such as a sheet scan or the monster catalogue, Chrome may load a D&D Beyond page in a temporary inactive tab so you are not pulled away from your page. The tab closes when the request finishes.
Will it type over what I am writing in Roll20 chat?
No. It posts through Roll20's own chat box but never overwrites a draft you are typing.
Do I need a Roll20 Pro subscription or a Mod script?
Not for the main features. Turn Order, chat, token bars, light, vision and spell templates are driven through the page itself. Only the selected-token roll, exact timers and synchronized deletion need a Mod in a Pro game.
Which of my players' data does it change?
On D&D Beyond it changes HP, temp HP, the max HP modifier, conditions, exhaustion and death saves, and, only when you ask, inventory, coins and notes. In Roll20 it changes tokens, bars, chat and the Turn Order. Untick Write HP back to D&D Beyond on the DM Screen's Party overview to stop the HP and status writes.
Privacy
It reads only the supported D&D Beyond, Roll20 and DM Screen pages, plus D&D Beyond's own character data using your signed-in session: for live reads it asks D&D Beyond for a short-lived access token, keeps it in the extension and uses it only for requests to D&D Beyond. It reads Roll20 chat only for lines the DM Screen acts on (a typed done, roll cards and dice rolls), and it does not collect passwords, cookies or payment details, run analytics or ads, or send your game data to the developer. What it reads goes to the DM Screen tab you have open, where it may be saved in your DM Screen profile, or to the Compass app on the same computer over 127.0.0.1, which cannot leave your machine.
Feedback
The alpha is open and what breaks is the point. Tell us what happened, what you expected, and which tool.