🧟‍♂️ PZColab — Free Project Zomboid Dedicated Server on Google Colab

Read this in: Español 🇪🇸

Run your own free Project Zomboid dedicated server in the cloud using Google Colab — no VPS, no port forwarding, no credit card. Works with Build 42 (stable) and Build 41 (legacy), installs everything automatically with SteamCMD, persists your world on Google Drive, and exposes the server to your friends through a Playit.gg tunnel.

This is an open-source tool for the community: spin up multiplayer Project Zomboid servers in minutes, free of charge, and stress-test mods, maps and configurations with zero infrastructure cost.

📑 Table of Contents

• ✨ Features
• 🚀 Quick Start
• 🎮 Supported Game Versions
• 📦 Installing Mods (Easy Mode)
• 🛠️ Server Operations
• 🧠 Log Diagnostics
• ❓ FAQ
• ⚠️ Important Notes
• 🤝 Contributing
• 📄 License

✨ Features

• One-click deployment: automatically installs system dependencies, SteamCMD and the Project Zomboid dedicated server.
• Version selector: b42 stable (recommended), b41 legacy and b42 unstable — one synchronized choice shared across all cells via a state file on Drive.
• No port forwarding: built-in Playit.gg tunnel gives your server a public address anyone can join.
• Cloud persistence: saves, configs and player profiles live on your Google Drive (/MyDrive/ZomboidSaves) — nothing is lost when the Colab session ends.
• Configurable memory: choose 4 / 6 / 8 GB of server RAM in Cell 3 — the notebook re-patches -Xms/-Xmx on every start and auto-caps the value to a safe limit based on the runtime's real RAM (never more than 8 GB on Colab).
• Easy Workshop mods + collections: paste a Workshop URL or numeric ID (one per line) — or a whole Steam collection — and the notebook downloads each item via SteamCMD, auto-detects the real Mod ID from its mod.info, classifies them (Libraries / UI / Vehicles / QoL) and writes them to the server .ini without duplicates.
• Crash watchdog: the server auto-restarts on failure (configurable retry count).
• Clean shutdown: sends save then quit so the world is saved safely.
• Live console: a tail cell shows the server console in real time.
• Saves backup: one-click .tar.gz backups on Drive with configurable retention.
• Advanced log diagnostics: scans log files and groups errors per mod — Lua crashes, Steam Workshop failures, out-of-memory problems, server/port errors and save failures — naming the actual culprit and suggesting fixes.
• Anti-idle script: a browser console script that prevents Google Colab from disconnecting your session.

🚀 Quick Start

1. Open PZ_Colab_EN.ipynb in Google Colab (use the badge above or File → Open notebook → GitHub).
2. Run Cell 1 — pick the game version and install the server (mounts Google Drive automatically).
3. Run Cell 2 — claim your persistent Playit.gg tunnel (first time only).
4. Run Cell 3 — the server starts in the background. Share the IP/port that Playit assigns!

💡 Spanish speakers: use the Spanish version PZ_Colab_ES.ipynb — Español 🇪🇸.

🎮 Supported Game Versions

Option	SteamCMD branch	Description
b42 stable	Default (no beta)	Current stable build of Project Zomboid. Recommended.
b41 legacy	-beta legacy41	Legacy 41.x build, for servers with older mods.
b42 unstable	-beta unstable	Unstable Build 42 branch, for testing new features.

The selected version is stored in MyDrive/ZomboidSaves/.pzcolab_state.json and reused by every other cell. Re-running Cell 1 is fast: if the server is already installed with the same version it skips the download; if you switched versions it stops the running server and reinstalls automatically.

📦 Installing Mods (Easy Mode)

In Cell 4, paste one mod per line — the Workshop URL or just the numeric ID:

https://steamcommunity.com/sharedfiles/filedetails/?id=2902678
2861456062
https://steamcommunity.com/sharedfiles/filedetails/?id=2750177123

You can also paste Steam collection URLs — they expand automatically. The cell downloads each item with SteamCMD, reads the real Mod ID from its mod.info (so you never need to know it), classifies them (Libraries → UI → Vehicles → QoL load order) and updates the .ini without duplicates, keeping your previous mods. The final report shows the mods' real names.

If automatic detection fails for a mod, use the advanced format URL|ModIDManual on that line.

The notebook also flags possible build incompatibilities (b41 vs b42) by scanning each mod's Workshop page, and warns about missing required dependencies (require= in mod.info) before you restart the server — the report shows each mod's real name, type and required dependencies.

🛠️ Server Operations

• Cell 3.1 — Live console: watch the server output in real time (stop with the ⏹ button).
• Cell 3.2 — Clean shutdown: saves the world and shuts the server down safely.
• Cell 5 — Backup: creates a .tar.gz of your saves in MyDrive/ZomboidSaves_backups with retention of the last N copies.
• Anti-idle (end of notebook): paste the browser script into the Colab page console (F12) to keep the session alive.

🧠 Log Diagnostics

If the server fails to boot or mods misbehave, run Cell 4.1 — Server Inspector & Advanced Diagnostics. It analyzes your Drive logs and prints:

• Exact number of critical Lua errors.
• The mod/script responsible for the failure.
• Steam Workshop connection alerts.
• Out-of-memory problems (with a hint to raise memory in Cell 3 or reduce players/mods), server/port errors and save failures.

❓ FAQ

Is it really free? Yes — Google Colab's free tier runs the server at no cost (session-limited to ~12 hours). A VPS or dedicated host is not required.

Does it work with Steam Workshop mods? Yes. Cell 4 downloads mods via SteamCMD and writes them to the server configuration automatically, including Steam collections.

Do I need to open ports on my router? No. Playit.gg creates a public tunnel without port forwarding.

How much RAM does the server use? Cell 3 lets you pick 4, 6 or 8 GB. The notebook automatically caps your choice to a safe value based on the runtime's real RAM (8 GB max on Colab's ~12.7 GB machines — the rest is reserved for the system, the tunnel and Colab itself).

Will my world be lost when Colab disconnects? No. The world and configs are stored on your Google Drive and reloaded on the next session.

Can I play with friends on b41 and b42? Yes — pick the version in Cell 1; the notebook installs the matching dedicated server branch (legacy 41 or stable 42).

⚠️ Important Notes

• Playit.gg is pinned to v0.15.26 on purpose (Colab console compatibility). Do not upgrade.
• Colab limits: free sessions last up to 12 hours with an inactivity timeout (~90 min). Use the notebook's anti-idle script and restart the server after reconnecting.
• Port changes: if you change the UDP port in Cell 3, update the matching tunnel in your Playit.gg dashboard.

🤝 Contributing

Pull requests are welcome! This project aims to be a solid base for the community to stress-test mods, maps and configurations in multiplayer environments without local infrastructure costs. Found a bug or have ideas to reduce RAM/CPU usage on Colab? Open an Issue.

📄 License

This project is licensed under the MIT License. Free to use, modify and distribute for your own testing.