Nested interactive maps
Upload a world map, then drill into regions, towns and individual buildings. Zoom and pan stay smooth no matter how deep the hierarchy goes.
Your campaign, under glass
D20 Atlas turns your maps into a living table. Drop pins, peel back the fog, move the party, and push exactly what you want onto a second screen. Ambience plays in true 3D around the table, and your notes, NPCs and monsters stay one click away.
No sign-up, no subscription. Your campaigns are stored locally on your own device.
d20atlas.com — Dungeon Master view
4 levels
World → building
2 windows
DM + player view
100%
Local storage
$0
To get going
Everything on one canvas
Built for the way you actually run a session
Prep on Saturday, run on Sunday. Every tool lives on top of the map, so you never lose the thread mid-encounter.
Fog of war
Reveal the map as the party explores. What you uncover on your screen appears instantly on theirs — nothing else leaks through.
Locations that hold their lore
Pin cities, dungeons, shops and shrines with custom markers. Each one carries its own Markdown notes and can link straight to a deeper map.
NPCs, monsters & PCs
One unified roster with health, stats, tags and split notes — a public side for the table and a private side just for you.
In-game clock
Advance from morning to midnight and watch NPC schedules follow along. Time finally means something at your table.
3D positional soundboard
Every sound gets a seat at the table. Place ambience and effects front, centre or behind the party and they arrive from that direction — real spatial audio, not a stereo slider.
Handouts & full-screen reveals
Push portraits, letters and set-piece art straight to the player window the moment you need them — and pull them back just as fast.
Two screens, one truth
A player view that only shows what you allow
Pop open a second window, drag it to the TV, and run the table. The player view mirrors your map, your fog, and your party marker in real time — and nothing else.
- Map changes, fog and party movement sync instantly
- Toggle individual locations visible or hidden
- Push an image full-screen for a dramatic reveal
- Your GM notes never cross the line
Prep that pays off
Every NPC, monster and party member in reach
Build your cast once and reuse it across sessions. Track hit points mid-combat, filter by tag when the party wanders somewhere unplanned, and spin up a statblock from a template in seconds.
- Markdown notes with a public and a GM-only side
- Live HP and status tracking during encounters
- Party position and movement history on the map
- Templates and a built-in bestiary to start from
The one nobody else has
Sound that comes from somewhere
The soundboard runs on the Web Audio spatial engine, so every track is positioned in three dimensions rather than panned left and right. Put the waterfall front-centre, the goblin drums back-left, and the storm all around — your players hear the room, not a playlist.
- Five speaker positions: centre, front L/R, back L/R
- Layer several ambiences at once, each in its own place
- A distance control per sound — near and looming, or far off
- Falls back to stereo panning on hardware that can't do 3D
Four steps
From blank map to first session
No install, no configuration. Open the app and start building.
Create a campaign
Name your world. Everything you make from here is scoped to it.
Upload your maps
Drop in images and nest them — continent, kingdom, city, tavern cellar.
Populate the world
Pin locations, write notes, and fill the roster with NPCs and monsters.
Open the player view
Cast the second window to a screen and lift the fog as they explore.
Questions
Good to know
Where is my campaign data stored?
Entirely in your own browser, using IndexedDB. There is no server and no
account — which also means your data lives on the device you created it on.
Back up anything you would hate to lose.
Do my players need accounts or a link?
No. The player view is a second window on your own machine, meant for a TV
or shared screen at the table. Nothing is published online.
Is the 3D audio really 3D?
Yes. The soundboard uses the Web Audio spatial engine, so each track is
placed at a point around the listener — centre, front left or right, back
left or right — instead of being panned across two channels. On hardware
that doesn't support it, sounds fall back to stereo panning automatically.
Does it work offline?
Once the app has loaded, your maps and notes are read from local storage,
so a flaky connection at the game table won't interrupt the session.
Which systems does it support?
D20 Atlas is system-agnostic. It ships with a d20-style bestiary and
statblock fields, but the maps, locations and notes work for any tabletop
game you run.
What does it cost?
Nothing. There is no subscription, no paywalled map slots and no upsell.
The party is waiting
Open D20 Atlas, upload a map, and have something ready before the next session starts.