Session Forge is an offline game master toolkit for fantasy tabletop RPGs, made by Donald Stelling of Digital Underground. Instead of another long PDF, it is a single HTML hub that the GM opens in a web browser and uses at the table to prepare and run sessions. It holds 14 tools: encounters, NPCs, loot, initiative, session notes, dungeons, taverns, quests, rumors, villains, weather and travel, settlements, a one-click one-shot outline, and a short GM playbook.
Tools for running the table
- Encounter Forge builds fights on an XP budget set by party level, party size and difficulty (Easy to Deadly). Each encounter comes with a motive and a twist, and the creatures are drawn from 198 original 5e-style stat lines.
- Initiative Tracker handles HP, AC, conditions, group adds and d20 rolls. Rounds and turn order save automatically, so combat survives closing the browser. Fights made in Encounter Forge can be sent straight into the tracker.
- Session Notes saves as the GM types, offers random sparks for quick ideas, and keeps a full archive that can be restored.
- GM Playbook explains how to use the tools live without slowing the game down.
Generators
- Full Session: a one-click one-shot outline with a hook, NPCs, a villain, a journey, two fights, a site, treasure and a twist.
- NPC Generator: 8 naming cultures, plus role, voice, quirk, secret and adventure hook, and a "crowd of six" mode.
- Loot Tables: common to very rare items, plus gems, art objects and 64 curses.
- Taverns & Shops: taverns and shops with priced wares.
- Dungeon Builder: dungeons of 3 to 12 rooms, with a boss scaled to the party.
- Quest Hooks, Villain Forge and Settlements.
- Rumor Mill: rumors with a GM-only truth rating.
- Weather & Travel: 6 climates and 4 seasons.
On every generator, the GM can lock a line and reroll the rest, go back through a saved history of the last 20 rolls, copy results as text or Markdown, download them as .md or .txt, and send them to Session Notes in one click. Seeds are repeatable, so the same seed always gives the same result.
How it works
The GM downloads a ZIP, opens index.html and bookmarks it for game night. After that one download, Session Forge runs fully offline with no account. Data is saved in the browser, and the home page has backup and restore. It works in a browser on desktop and on mobile.
Systems and fit
The stats are
5e 
https://groupfinder.gg/library/dungeons-dragons-5e-2014 -flavored so they feel familiar, and the content is easy to reskin for
OSR https://groupfinder.gg/library/old-school-renaissance-osr-2000 games,
Pathfinder https://groupfinder.gg/library/pathfinder-2nd-edition-2019 or homebrew settings. All generator content is original; it is not a dump of official rulebook text. Session Forge suits GMs running 5e-compatible fantasy, one-shots and west-marches campaigns, and GMs who improvise and need ideas fast. It is not a virtual tabletop plugin: it runs locally in the browser and does not connect to
Foundry VTT https://groupfinder.gg/library/foundry-virtual-tabletop-foundry-vtt or
Roll20 https://groupfinder.gg/library/roll20 .
Price and license
Session Forge is a one-time purchase from CAD$14.99 (pay what you want above that) on Gumroad. The license is personal, single-GM use. Version 2 raised the toolkit from 6 tools to 14, and earlier buyers get v2 free by downloading again; their v1 saves carry over.