Open Dungeon Master

AI Dungeon Master · D&D 5e · Runs on your machine

Multiplayer D&D 5e campaigns run by an AI Dungeon Master, or by a human one. Bring a local model, an API key, or the ChatGPT or Grok subscription you already pay for. The app tracks every rule for you, so nobody has to.

Download for Windowsversion 0.21.2 · auto-detected

Get it on Google Playfor Android

Server apphost a group · v0.30.2

Free & open source · MIT licensed · system requirements · watch the trailer

No hosting required

You can run it on your own hosted server, but you don't have to. Play with friends anywhere without hosting a thing, with or without AI features.

See it played

Watch the showcase

Plays from YouTube once you press play.

Three ways to play

Every feature, with or without hosting

Nothing is locked behind a server. Pick the setup that fits your table, and change your mind any time.

FULL EXPERIENCE · AI ON

Hosted server

One machine runs the app; your party joins with an invite code. Real-time multiplayer, voice, and the AI Dungeon Master on a local model, an API key, or a CLI agent signed in on that machine.

HUMAN DM · NO SERVER TO RUN

No-server multiplayer

Host a world from the desktop or Android app and share one room code. Friends join from anywhere, live voice included, and a human runs the table. Nothing to install beyond the app.

AI FEATURES · NO HOST

Bring your own AI

Paste your OpenAI key once, or on desktop let Codex, Grok Build or another agent you already pay for narrate and paint, and the full AI Dungeon Master switches on for every campaign on your device. No server to run and no local model required.

Not sure which fits? The knowledge base walks through all three.

Embers of the Saltglass Coast, round one against two salt-glass husks: the initiative portraits run across the top, the chronicle of the Dungeon Master's narration is on the left, the battle map sits above the hand of cards in the middle, and the quest, combat tracker and party cards are on the right

Embers of the Saltglass Coast on a phone: Dungeon Master narration above the hand of cards, the Do, Say, OOC and Direct input modes and the table navigation bar

A live session

The party's portraits and hit points down the side, initiative across the top, the battle map and quest at hand, and your turn's cards below, all kept by the app.

What's at the table

A whole VTT that runs itself

The multiplayer table

Create a campaign, share an invite code, ready up in the lobby, and play in real time with a party lead who steers settings, rolls and turn order.

Your AI as Dungeon Master

A local model, an API key, or a CLI agent subscription like Codex or Grok Build. The model narrates, asks for rolls, runs combat and plays every NPC, following a secret story arc it regenerates as the campaign moves. It never owns the numbers.

III

Battle maps & scene art

Optional ComfyUI paints character portraits, inline scene art and top-down battle maps with per-character line of sight. Missing? It fails soft to a placeholder.

Live voice chat

An in-process SFU with no third-party service, no account, and no audio leaving your machine. Turn-taking rides the floor, with optional proximity, whispers and side rooms.

Run the table yourself

A human-DM mode where a person narrates and the app keeps sheets, dice, maps and the record straight, with a DM console and an assisted mode that delegates to the AI.

Workshop prep space

Author maps, bosses, NPCs, encounters, roll tables and lore outside any campaign in a graphical editor, then import them into new campaigns. Everything clones.

How it works

The narrator never owns the numbers

The app owns the rules.
Dice, hit points, spell slots, conditions and the death track are computed and clamped by the app. The model touches game state only through validated, audit-logged tools.
The AI drives the table.
It requests rolls, starts and runs combat, plays NPCs and companions, and decides when to spotlight a player, treating messages as intent, never outcome.
It follows a secret story arc.
Every campaign gets a hidden spine, refreshed with a small clamped delta as chapters close, so the plot advances without the model rewriting history.

What each setup gives you.

Capability	Hosted	No server	Own key
Multiplayer table	Yes	Yes	Yes
App-enforced 5e rules	Yes	Yes	Yes
Live voice chat	Yes	Yes	Yes
AI Dungeon Master	Yes	No	Yes
AI scene art & maps	Yes	No	optional
Nothing in the cloud	Yes	Yes	No
No hosting required	No	Yes	Yes

New to AI Dungeon Masters?

The suggested setup

The cheapest way to a full AI Dungeon Master is something you may already have. A ChatGPT or Grok subscription comes with a command-line agent that both tells the story and paints the scene art, and the desktop app can hand it the table. A gaming PC with a 16 GB graphics card can run the storyteller itself, for free.

Story and pictures

ChatGPT Plus

Includes Codex, which narrates and paints portraits, scene art and maps on the same plan. The app runs one test turn and one test picture on your machine first.

Story and pictures

SuperGrok

Includes Grok Build (so does X Premium+), which also narrates and paints. The app tests a turn and a picture on your machine before it plays.

No subscription · free and private

A gaming PC with a 16 GB graphics card

The desktop app downloads gpt-oss-20b and runs it on your card: no account, no usage limits, and nothing leaves your computer. Choose Local AI on this machine and its Story model for 16 GB. Battle maps are drawn either way; scene art needs a picture service on top. What each card runs

Pick one.
One plan is enough, and you do not need an API key. With a 16 GB card you need neither.
Install the desktop app.
Windows, macOS or Linux. On Linux take the AppImage, .deb or .rpm: the Flatpak sandbox cannot start an agent or a local model.
Connect it.
The first launch asks who tells the story; later, Story AI on the home screen. An agent you already have checks that Codex or Grok Build is installed and signed in, and shows the one command to run if it is not.
Host and invite.
Press Share online and send the room code. Friends join from their own app, phones included. Only the host needs the plan or the graphics card.

Download for Windows Bring your own agent, in detail

An agent's turns and pictures count toward the plan's usage limits, and pictures use them faster than text; if a limit runs out mid-session, the lead sends the turn again once it resets. Claude Code and opencode narrate too, but cannot paint.

Before the table sits down

Prep it in the workshop

Storyboards, monsters, NPCs, encounters, roll tables and lore, built outside any campaign and imported when you want them. Battle maps draw themselves from a sentence.