Entity ownership, handles and network IDs in FiveM

Most “it works for me but not for other players” bugs in FiveM come from one misunderstanding: an entity handle is a local number. The vehicle that is handle 131842 on your client is a different number on the server and on every other client. The shared name for an entity is its network ID, and every networked entity also has an owner — the one client that simulates it.

A client only knows entities near it. If the server sends a network ID for a vehicle across the map, the client cannot resolve it until it is in range — wait with NetworkDoesEntityExistWithNetworkId before converting.

local function waitForNet(netId, timeout)
    local deadline = GetGameTimer() + (timeout or 5000)
    while not NetworkDoesEntityExistWithNetworkId(netId) do
        if GetGameTimer() > deadline then return nil end
        Wait(0)
    end
    return NetworkGetEntityFromNetworkId(netId)
end

With OneSync every networked entity has an owner client that runs its physics and sends its state. NetworkGetEntityOwner(entity) returns the owner — a server ID on the server, a player index on the client. Only the owner’s changes stick; when your client changes an entity it does not own, the owner overwrites it on the next update.

local function requestControl(entity, timeout)
    local deadline = GetGameTimer() + (timeout or 2000)
    NetworkRequestControlOfEntity(entity)
    while not NetworkHasControlOfEntity(entity) do
        if GetGameTimer() > deadline then return false end
        Wait(0)
        NetworkRequestControlOfEntity(entity)
    end
    return true
end

if requestControl(veh) then
    SetVehicleFixed(veh)
end

When the owner leaves the area or disconnects, ownership migrates to another nearby client. If nobody is relevant any more, the server removes the entity by default. SetEntityOrphanMode(entity, mode) on the server changes that:

KeepEntity only stops the server deleting it; a client can still delete it. Use it for things that must survive, like a placed prop, and clean them up yourself.

Instead of keeping tables keyed by network ID, attach data to the entity itself with an entity state bag: Entity(veh).state:set('fuel', 62.0, true). It follows the entity everywhere. See state bags.