Campaign Codex

One engine · many worlds

Choose your world.

Campaign Codex is a deterministic rules engine built to hold more than one tabletop universe. Pathfinder 1st Edition is live today — five more worlds are already on the map.

The Campaign Codex multiverse map: one floating island in space divided into six districts, one per game system — a fantasy castle-city, a space-opera spaceport, a retro-futurist frontier outpost, a neon waterfront metropolis, a gothic Victorian district, and a ruined city built into a crashed spacecraft. Pathfinder 1st Edition* Starfinder 1st Edition* SOON Traveller* SOON Cyberpunk Red* SOON World of Darkness* SOON Solarus Arcanum SOON

Pathfinder 1st Edition is live — click its city to get started. Everything else on the map is coming soon. * Third-party system names are trademarks of their respective owners.

Universe 01 — Pathfinder 1st Edition

Free & open source · Linux, macOS & Windows

The character sheet that shows its work.

Campaign Codex computes your Pathfinder 1st Edition character deterministically — every bonus, save, and prerequisite traces back to the exact rule that produced it. No black box, no eyeballed math, no guessing at the table.

Get started View source on GitHub

  • Source: MIT
  • Game data: per-source license
  • Your characters stay on your disk

Why Campaign Codex

A rules engine first, a character sheet second — built so the numbers are never a mystery.

Rules you can verify

Every computed value traces to the source text that produced it. If the engine can't back a number with a rule, it says so instead of guessing.

Built from the real rulebooks

Codex parses the actual Pathfinder 1e sourcebook data — not a hand-typed approximation — into a structured, queryable corpus. Pathfinder is the first universe; the same engine is built to seat other tabletop systems, sci-fi included.

Free, open, and yours

Source code is MIT-licensed; the game rule data ships under its own license per book (OGL, CC, or ORC) — see the licensing breakdown below. No subscription, no telemetry. Release 1 adds a GM's toolbox and a campaign mode so your table can share content over your own Google Drive.

What you can do

Everything a table actually needs, not an engineering demo.

Build a character

Walk through race, class, feats, and gear against the real Pathfinder 1e ruleset — no flipping between three books to check if a choice is legal.

Save and load

Every character is saved to your own disk. Close the app, come back next session, and pick up exactly where you left off.

Every detail calculated

Attack bonuses, saves, skills, AC — every number on the sheet is computed for you and traces back to the rule that produced it.

Print for the table

Get a clean, ready-to-print character sheet for whenever you'd rather have paper in front of you than a screen.

Share with your table

Campaign mode lets everyone in your group share characters and campaign content with each other over your own Google Drive.

DM Toolkit

Build encounters and keep session notes in the same place you're running the game, instead of a pile of scattered documents.

Early access

Campaign Codex is under active development. Today, the fully reliable path is a single-class Fighter, levels 1–3, any race — every other combination returns an honest "not yet supported" instead of a fabricated number. New classes and levels land every release.

See full project status →

Install & run

Active development happens on Linux — that's the platform every change is proven against first. Every push also auto-publishes alpha builds for Linux, macOS, and Windows, so you don't need a toolchain just to try the app.

Download a build

These are alpha builds, published automatically from the latest code — expect rough edges. Grab the newest alpha-vX.Y.Z release from the releases page.

Platform Linux macOS Windows
Download

Grab the .AppImage (portable, no install) or the .deb (Debian/Ubuntu).

Grab the .dmg.

Apple Silicon (M-series) only for now — Intel Mac builds haven't landed yet.

Grab the .msi or the .exe installer.
Run it 
chmod +x Codex_*.AppImage
./Codex_*.AppImage

Or with the .deb:

sudo apt install ./Codex_*_amd64.deb

Open the .dmg and drag Codex into Applications, same as any Mac app.

Run the .msi or .exe and follow the installer.

Build from source

Only needed if you're developing against Codex, not just running it. Five steps from a clean machine to a locally built binary.

Step Linux Verified macOS Unverified Windows Unverified
1. System dependencies 
sudo apt update
sudo apt install libwebkit2gtk-4.1-dev \
  build-essential curl wget file libxdo-dev \
  libssl-dev libayatana-appindicator3-dev \
  librsvg2-dev pkg-config
 
xcode-select --install

Installs the Xcode Command Line Tools (Clang, make, git) that Tauri's macOS build needs.

Install Visual Studio Build Tools with the "Desktop development with C++" workload.

Windows 11 ships the WebView2 runtime already; on Windows 10, install it from Microsoft's WebView2 page.
2. Rust toolchain 
curl --proto '=https' --tlsv1.2 https://sh.rustup.rs -sSf | sh
. "$HOME/.cargo/env"
cargo --version

Install via rustup.rs, choosing the MSVC toolchain when prompted, then verify in a new terminal:

cargo --version
3. Node.js LTS Install via your normal bootstrap path, then verify with node --version and npm --version.
4. Build the app 
cd apps/desktop
npm ci
npm run build
npx tauri build --debug
5. Launch it 
cd apps/desktop
npx tauri dev

Full onboarding and troubleshooting lives in README.md.

Project

Repository: github.com/electricm0nk/codex

Owner: electricm0nk

License (source code): MIT — see LICENSE.

License (game rules data): Not MIT-licensed. Each dataset carries its own license — Open Game License v1.0a, Creative Commons, or ORC. See LICENSING.md for full attribution obligations.

Trademarks: see the full breakdown below.

For developers

Everything below is engineering detail, not required reading for players.

Third-party trademarks

Campaign Codex is an independent, unofficial project. The systems below are named on the multiverse map above to describe planned support; naming them is not a claim of affiliation or endorsement.

  • Pathfinder and Starfinder are trademarks of Paizo Inc. Campaign Codex is not affiliated with or endorsed by Paizo.
  • Traveller is a trademark of Far Future Enterprises, published under license by Mongoose Publishing. Campaign Codex is not affiliated with or endorsed by Far Future Enterprises or Mongoose Publishing.
  • Cyberpunk RED is a trademark of R. Talsorian Games, Inc. Campaign Codex is not affiliated with or endorsed by R. Talsorian Games.
  • World of Darkness is a trademark of Paradox Interactive AB. Campaign Codex is not affiliated with or endorsed by Paradox Interactive or White Wolf Entertainment.
  • Solarus Arcanum carries no asterisk on the map above — it's an original Campaign Codex setting, not a third-party system.