Co-GM

The GMing tool that stays out of your way.

Run games, keep notes, and stay organized using a tool built specifically for GMs.

Co-GM uses Northlight for sign-in. No Northlight account yet? Create one.

Coming from cogm.tech? Import your campaigns, notes, libraries and plan from your old account.

Run your campaign from one page

Keep track of your campaign's sessions, notes, events and characters.

Notes, generators, dice, calendars, rules and lore sit side by side and work together. No more switching between tabs or apps.

“Co-GM strikes the perfect balance—powerful enough for complex campaigns, simple enough to stay out of my way so I can focus on the game.”

— Longtime Co-GM User

Campaign page: Your session, scratch pad, timeline, tools and notes on one screen while you play.
Linked notes: Type @, #, ! or any symbol you set up to link a note. Every note lists where it is mentioned.
Generators: Build random tables and roll them straight into your session.
Calendars: Make your world's calendar, with its own months, leap years and holidays, and see what happened on each day.
Compendia: Paste in your rules or lore and look up any entry mid-game.
Templates: Give each kind of note a template, so a new character or location starts filled in.
Dice: Write dice like 2d6+3 in any note and click to roll.
Combat tracker: Run encounters from a note: a monster list per ruleset, initiative or free order, turns and rounds, and a bestiary you can share.
Workshop: Use generators, compendia, templates and calendars that other GMs have shared, and share your own.
Setup assistant: Answer a few questions about your game, and an assistant sets up your first campaign. Free accounts get a plain setup form instead.
Agent access: Let an AI agent on your Northlight runtime read and write your notes, libraries and sessions with the Co-GM command line (Standard and Legendary).
On your phone: Read and edit your notes at the table.

Type a symbol and a name to link a note. Click a link to a note that doesn't exist yet, and Co-GM creates it.

Rename a note and every link follows. Each note shows where it is mentioned, and the graph shows how everything connects.

Build generators from tables, with weights and tables inside tables.

Roll one during play and insert the result at your cursor in a session or any note, or copy it.

Name your own days and months, set their lengths, and add leap years, eras and recurring events like holidays and moons.

Type /today in a note to mark the in-world date, and the timeline shows it on that day.

Paste a long document, and Co-GM splits it into entries.

Turn a compendium on in any campaign, search it mid-game, and link to its entries from your notes.

Write dice like 2d6+3 or 4d6kh3 in any note, and click to roll.

Recent rolls stay on screen, so you can check what came up.

Browse generators, compendia, templates and calendars that other GMs have published, and choose which campaigns get them.

Publish your own for anyone to use.

Co-GM uses Northlight for sign-in. No Northlight account yet? Create one.