Where do the config files go?

Both files live in the Zomboid/Server folder of whatever account runs the server. On Windows that is C:\Users\your-username\Zomboid\Server, on Linux it is ~/Zomboid/Server. Stop the server before you upload them: a running server writes its own copy of both files when it shuts down, which will overwrite anything you replaced while it was live. Some hosts move the folder elsewhere with a cachedir launch argument, so if you cannot find it, search for a file ending in _SandboxVars.lua.

Why are there two files instead of one?

They cover different things and the game reads them at different points. The .ini is the server process: slots, ports, passwords, mods, safehouse rules, backups. The SandboxVars.lua is the world simulation: zombie population and behaviour, loot rates, day length, when utilities shut off. You can edit the .ini between restarts as often as you like, but several sandbox settings are locked in when the world first generates, so it is worth getting those right before anyone starts a character.

Do I have to call my server servertest?

No. Both file names come from the -servername argument the server starts with, and servertest is only the default. If you start the server with -servername myserver, it will look for myserver.ini and myserver_SandboxVars.lua instead. Set the server name field at the top of this page to whatever your server actually uses and the generator will name the downloads to match. Getting this wrong is the single most common reason edited settings appear to do nothing: the server is reading a different pair of files.

How do I add mods to a Project Zomboid server?

Mods need two entries in the .ini and they are not interchangeable. WorkshopItems takes the numeric Workshop IDs from the Steam Workshop URL, which is what the server downloads on boot. Mods takes the mod IDs from each item's description, which is what actually gets loaded, in load order. Separate both lists with semicolons. One Workshop item can contain several mod IDs, so the two lists do not always have the same length. Map mods also need adding to the Map line, before the vanilla entry.

How much RAM does a Project Zomboid server need?

Start at 3 GB for a small friends server and add roughly 1 GB per 8 to 10 players, so a 32 slot server usually wants 6 to 8 GB. The real driver is not the slot count but how spread out players are, because the server keeps map cells loaded around every group. Ten players in one town cost far less than ten players in ten towns. Heavy Workshop mod lists, big built-up bases and a long-lived world with a lot of dropped items all push it higher.

Project Zomboid server tools

Project Zomboid Server Config Generator

Build both files a Project Zomboid dedicated server needs: the SandboxVars.lua that controls zombies, loot and the world, and the .ini that controls slots, PvP, ports, mods and safehouses. Pick a playstyle, adjust anything, then copy or download.

Game build

Build 42 writes schema VERSION 6, uses the float loot multipliers, the MultiplierConfig XP table and the Basement settings.

Server name

Both file names come from this. You will save them as servertest.ini and servertest_SandboxVars.lua. It has to match the -servername your server starts with, which is servertest by default.

Playstyle presets

The game's own playstyles, value for value from the vanilla files. Load one, then change whatever you like.

Checks

32 slots suggests roughly 6 GB of RAM. Project Zomboid loads map cells around each group of players, so spread-out players cost more than the slot count implies.

Save world every is 0, so the world is only written on shutdown. A crash then loses everything since the last clean stop.

Loot never respawns with these settings. That is the vanilla experience, but on a server running for months late joiners will find empty houses.

Save the files as servertest_SandboxVars.lua and servertest.ini in your server's Zomboid/Server folder.

SandboxVars = {
    VERSION = 6,
    Zombies = 4,
    Distribution = 1,
    ZombieRespawn = 4,
    ZombieMigrate = true,
    DayLength = 4,
    StartMonth = 7,
    StartDay = 9,
    StartTime = 2,
    TimeSinceApo = 1,
    NightDarkness = 3,
    NightLength = 3,
    WaterShut = 2,
    ElecShut = 2,
    WaterShutModifier = 14,
    ElecShutModifier = 14,
    Alarm = 4,
    LockedHouses = 6,
    Temperature = 3,
    Rain = 3,
    ErosionSpeed = 4,
    FireSpread = true,
    GeneratorSpawning = 4,
    GeneratorFuelConsumption = 0.1,
    AllowExteriorGenerator = true,
    SurvivorHouseChance = 3,
    VehicleStoryChance = 3,
    ZoneStoryChance = 3,
    AnnotatedMapChance = 4,
    HoursForCorpseRemoval = 216.0,
    BloodSplatLifespanDays = 0,
    AnimalSoundAttractZombies = true,
    AnimalMetaPredator = false,
    AnimalMatingSeason = true,
    FoodLootNew = 0.8,
    CannedFoodLootNew = 0.6,
    LiteratureLootNew = 0.6,
    SkillBookLoot = 0.6,
    RecipeResourceLoot = 0.6,
    MedicalLootNew = 0.6,
    SurvivalGearsLootNew = 0.6,
    WeaponLootNew = 0.6,
    RangedWeaponLootNew = 1.2,
    AmmoLootNew = 0.6,
    MechanicsLootNew = 0.6,
    OtherLootNew = 0.8,
    ClothingLootNew = 0.6,
    ContainerLootNew = 0.6,
    KeyLootNew = 0.4,
    MediaLootNew = 0.6,
    CookwareLootNew = 0.6,
    MaterialLootNew = 0.6,
    FarmingLootNew = 0.6,
    ToolLootNew = 0.6,
    RollsMultiplier = 1.0,
    ZombiePopLootEffect = 0,
    HoursForLootRespawn = 0,
    MaxItemsForLootRespawn = 5,
    ConstructionPreventsLootRespawn = true,
    SeenHoursPreventLootRespawn = 0,
    MaximumLooted = 25,
    DaysUntilMaximumLooted = 90,
    WorldItemRemovalList = "Base.Hat, Base.Glasses, Base.Maggots, Base.Slug, Base.Slug2, Base.Snail, Base.Worm, Base.Dung_Mouse, Base.Dung_Rat",
    HoursForWorldItemRemoval = 24.0,
    DaysForRottenFoodRemoval = -1,
    StatsDecrease = 3,
    EndRegen = 3,
    Nutrition = true,
    StarterKit = false,
    CharacterFreePoints = 0,
    ConstructionBonusPoints = 3,
    InjurySeverity = 2,
    BoneFracture = true,
    ClothingDegradation = 3,
    RearVulnerability = 3,
    MultiHitZombies = false,
    AttackBlockMovements = true,
    AllClothesUnlocked = false,
    MuscleStrainFactor = 0.7,
    DiscomfortFactor = 0.8,
    EasyClimbing = false,
    FoodRotSpeed = 3,
    FridgeFactor = 3,
    Farming = 3,
    FarmingSpeedNew = 1.0,
    FarmingAmountNew = 1.0,
    PlantResilience = 3,
    PlantAbundance = 3,
    NatureAbundance = 3,
    CompostTime = 2,
    MinutesPerPage = 2.0,
    LightBulbLifespan = 2.0,
    EnableVehicles = true,
    VehicleEasyUse = false,
    ZombieAttractionMultiplier = 1.0,
    CarSpawnRate = 3,
    InitialGas = 2,
    ChanceHasGas = 2,
    FuelStationGasMin = 0.0,
    FuelStationGasMax = 0.8,
    FuelStationGasInfinite = false,
    FuelStationGasEmptyChance = 20,
    LockedCar = 4,
    CarGasConsumption = 1.0,
    CarGeneralCondition = 3,
    CarDamageOnImpact = 3,
    DamageToPlayerFromHitByACar = 1,
    CarAlarm = 3,
    TrafficJam = true,
    PlayerDamageFromCrash = true,
    Basement = {
        SpawnFrequency = 4,
    },
    Map = {
        AllowMiniMap = false,
        AllowWorldMap = true,
        MapAllKnown = false,
        MapNeedsLight = true,
    },
    ZombieLore = {
        Speed = 4,
        SprinterPercentage = 0,
        Strength = 2,
        Toughness = 4,
        Transmission = 1,
        Mortality = 5,
        Reanimate = 3,
        Cognition = 3,
        DoorOpeningPercentage = 0,
        CrawlUnderVehicle = 5,
        Memory = 2,
        Sight = 5,
        Hearing = 5,
        ThumpNoChasing = false,
        ThumpOnConstruction = true,
        ActiveOnly = 1,
        TriggerHouseAlarm = true,
        ZombiesDragDown = true,
        ZombiesCrawlersDragDown = false,
        ZombiesFenceLunge = true,
        DisableFakeDead = 1,
    },
    ZombieConfig = {
        PopulationMultiplier = 0.65,
        PopulationStartMultiplier = 1.0,
        PopulationPeakMultiplier = 1.5,
        PopulationPeakDay = 28,
        RespawnHours = 0.0,
        RespawnUnseenHours = 0.0,
        RespawnMultiplier = 0.0,
        RedistributeHours = 12.0,
        FollowSoundDistance = 100,
        RallyGroupSize = 20,
    },
    MultiplierConfig = {
        Global = 1.0,
        GlobalToggle = true,
    },
}

Stop the server, upload both files to Zomboid/Server (on Windows that is C:\Users\your-username\Zomboid\Server), then start it again. A running server rewrites these files on shutdown and would overwrite your changes.

Only the settings this tool manages are written. Anything else keeps the server's own default, so these files are safe to drop in as they are.

How the two files fit together

A Project Zomboid dedicated server reads two files named after your server. The .ini is the server itself: how many slots, whether PvP is on, which ports it binds, which mods it loads, how safehouses work. The SandboxVars.lua is the world: how many zombies, how fast they are, how rare loot is, how long a day lasts, when the power and water cut out.

Changing the .ini is safe at any time. Changing SandboxVars.lua after the world has generated is not always: population, loot rates and infection settings apply straight away, but the start date, months since the apocalypse and anything that shaped the map at generation are already baked into the save. Decide those before your players start building.

Build 42 reworked the file. Loot rarity became a set of float multipliers, XpMultiplier became the MultiplierConfig table, several keys moved out of the .ini into SandboxVars, and the schema version went from 5 to 6. Pick the matching build at the top of the page, because a Build 41 file dropped onto a Build 42 server silently loses those settings.