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Modding Policy

Last Updated: 04/10/2022

Hello survivor! Here’s the scoop on modding Project Zomboid. By mods, we mean modifications of Project Zomboid (or part of it) and/or new content or tools made for it by you, whether standalone or integrated. Long story short, you can make mods, but must follow the rules below.

This Modding Policy should be read alongside the Project Zomboid Terms and Conditions (which are legally binding on you), Valve’s Mod Content Usage Policy, and Valve’s Steam Subscriber Agreement. We may update this Modding Policy from time to time – so we recommend you check it periodically.

1. Your responsibility

1.1. Modders are solely responsible for:

1.1.1. their mod, including (but not limited to compliance with any hosting platforms such as Steam Workshop).

1.1.2. obtaining the necessary consents or licences for any third-party materials in the mod. (This includes if you want to use assets or materials from another mod – you need their permission to use it yourself).

1.2. Users of mods are responsible for their usage of mods – we don’t check them, and we can’t be responsible for them.

2. Modding restrictions

2.1. If you are a player that uses mods: respect the time, dedication and talent of your favourite modders. Remember that they have lives too and are generally not remunerated for their time or skills. They will update their mods as soon as they can and haranguing them will not speed up the process.

2.2. Mod content. You are allowed to edit Project Zomboid in any way you want, provided that you do not:

2.2.1. edit it in such a way that it is either intentionally damaging to people’s PCs or other devices, removes the login system, or enables people to play Project Zomboid (or parts of it) without purchasing. This clearly also covers all future unreleased content and versions of Project Zomboid.

2.2.2. create nor publish content that is objectionable and inappropriate. This includes but is not limited to content that is intentionally offensive, abusive, obscene, discriminatory, racist, pornographic, aimed to harass someone or a group of people, threatening, hateful, xenophobic, invasive to the privacy of another person or group of people, sexist, and/or defamatory.

2.2.3. call or make your mod appear to be “Official”.

2.3. Donations. Modders are free to receive monetary/gift donations from the players who use their releases, and appreciate the time and effort put into them. However, having mods created exclusively for those who choose to donate (or separate ‘in-mod’ content and bonuses) is not allowed.

2.4. Commercialisation. Unless any arrangements to the contrary have been made with us, mod creators cannot sell access to a mod and/or mod content. Mod creators are permitted to work on commissioned mods provided such mods are not sold. Please see section 4 of the Terms & Conditions for more information on this.

2.5. Political Statements. We reserve the right to remove content that displays any overt political messaging (from any side of any argument, and from any nation) that we reasonably believe could cause disruption within our community or more broadly.

Whether The Indie Stone, or most, would agree with the statements made is not relevant – as it’s a dangerous precedent that modders can add political messaging of any kind that could silently update in the background without it being evident that messaging wasn’t made directly by the developers.

(If you don’t like a mod author’s choice to add anything you do not appreciate to their mod, unsubscribe, perhaps leave a polite comment if that is your wish, and move on. Harassment will not be tolerated.)

2.6. Hidden / Unexpected Content. Any hidden or unexpected content and/or messages made in updates to mods that are not flagged on the Steam Workshop description / pages or isn’t evident in the mod itself must have attribution VISIBLE as to where (and from whom) said content has originated.

2.7. Be Lovely. Following this mantra, we ask mod authors to be respectful to other players, other modders and the time everyone has put into supporting Project Zomboid. Do not say anything that is unlawful, gives rise to civil or criminal liability or could harm the game, its players, or The Indie Stone.

3. Ownership

3.1. You own mods that you create. We own Project Zomboid, our other property and everything in them.

3.2. We need a right to use your mods so that we can distribute them, and so that others can play them through Project Zomboid. In legal terms, you grant us a non-exclusive, permanent, sub-licensable, royalty-free, irrevocable, and worldwide licence to use, modify, reproduce, create derivative works from, distribute, transmit, perform communicate and exploit your mods (or any part of them) in connection with Project Zomboid.

In all circumstances Spiffo’s Workshop abides by the exact same rules as Valve for mods made for Project Zomboid and hosted on the Steam Workshop.

“It’s a sad fact, but in some cases content is [also being] lifted from one mod to another. It’s often a misconception that just because a mod is free to download, its contents are also free for you to take and choose from as you wish.”

“Even if a mod is free or not, the creators of any original work included within it (sounds, materials, models, source code) own the copyright for their work. This is true if you are a high-school kid, a corporation, or just some other modder who puts stuff together for fun. Every author gains these rights by default when they create their work.”

“The authors alone can decide how and who may use their work and have the law behind them should they decide to take issue of anything used without permission. If you see something in another mod that would be of use to you in your own mod or map, your first step should be to contact the mod team and then specifically ask the creator of the item you’re after. They and they alone can give you permission to use their work.”

“If you create contents for mods and don’t mind other people using your content, then it could save a lot of trouble and benefit the community as a whole if you release your works under a Creative Commons license. See the Official Website to select a License for your works.”

4. Third party content

4.1. Modification of other users’ workshop submissions is allowed under personal use, but you are NOT allowed to submit work that is not your own, without permission of the mod owner.

4.2. As mentioned in 1.1.2, if you put any third-party property into your mod, then it’s your responsibility to make sure it’s all done in an appropriate, legal fashion, including offering credit within the Workshop description of your mod.

4.3. Even if permission not to credit a mod owner is obtained, if a mod creator raises an issue with our moderation staff, failing to credit modders for any substantially unique or direct link to their work will potentially result in your own mod being delisted until credit is given.

5. Our use of your mods

5.1. We are, technically, permitted under Steam’s Subscriber Agreement to incorporate any mods submitted to Steam into Project Zomboid.

5.2. However, as a matter of policy, should this ever happen with Project Zomboid (and the relatively infrequent occasions when it has happened in the past) it is after direct communication and signed agreement between all parties. Upon allowing The Indie Stone to use a modification in the game modders cannot claim entitlement to any past, current or future profits from the game unless this is agreed upon at the time.

5.3. Separate from this, we reserve the right to implement any general gameplay ideas or features in Project Zomboid irrespective of whether mods exist that accomplish the same goal. While we will respect people’s personal creations and always ask for permission and offer credit within the game before intentionally including any code, art or dialogue directly from mods with the core game: we do this out of respect to the authors and are not legally obliged.

5.4. We say this primarily to protect ourselves from the potential for mods to beat us to features we already intend to add, and then having the origin of that idea disputed.

5.5. Our plans for Project Zomboid are long and varied, but have always closely aligned with the wants and desires of the community.

6. Representations and Warranties

6.1. You represent and warrant that:

6.1.1. your mod does not violate Valve’s Mod Content Usage Policy, the Steam Subscriber Agreement, or our Project Zomboid Terms and Conditions;

6.1.2. you have sufficient rights and permissions to the content within your mod, which includes – without limitation – any kind of intellectual property rights or other proprietary or personal rights.

6.1.3. the mod was originally created by you and/or that you have the right to distribute the mod and the entirety of its content.

7. Modpack Permissions

7.1. For the use of expansive modpacks, we are going to differentiate between the following three types:

7.1.1. Public. Public modpacks require permission for each and every mod included in the pack from their respective mod authors. If no explicit permission for modpack inclusion was given, this is the equivalent to it being denied. A complete list of included mods must be available in the description.

Using the Workshop’s Collection feature can also be considered instead, which keeps the relevant mods up to date and makes sharing the mod easier.

7.1.2. Semi-Private. These are packs that are usually tailored to a customised server experience, and are posted as “Unlisted” on the Steam Workshop. These modpacks still require permission. Mod authors who find their mods in an Unlisted modpack are still free to ask to have their mod pulled, or for the modpack to be removed from the Workshop until their mod has been taken out.

7.1.3. Private. These are packs solely intended for your personal use, and redistribution is strictly forbidden. Permission is not necessary as long as these types of modpacks are not available for public download. Private/personal-use modpacks are not to be published or made available for others to download under any circumstance. A modpack that is intended to be private but available to the general public is effectively published, and as such will require permissions.

8. Abandoned and Broken Mods

8.1. In some instances the community will step in where mods created by an absent user have become abandoned – or have been broken for a long time. If and when this occurs we ask the following:

8.1.1. That the Project Zomboid Steam moderation team is informed of your plans, and you have asked for their opinion via a private message, or failing that, an email to

8.1.2. That EVERY avenue has been explored in terms of contacting the original mod author to ask permission.

8.1.3. That the original mod author’s wishes are respected should they have left directions prohibiting expansion and/or reupload of their mod.

8.1.4. That should an abandoned mod be reuploaded with a working version, the original author is given FULL credit.

Thank you for your time and attention!

Modding is the lifeblood of the Project Zomboid community, and by adhering to these simple rules we can make Spiffo’s Workshop a better and more enjoyable place in which we can all build, play and survive.

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