A mod has the ability to depend on other mods, either required dependencies or optional dependencies. These are specified as comma separated lists in the mod's `mod.conf` file, `depends` and `optional_depends` respectively.

A mod's dependencies get loaded before the mod, such that API functions get defined and are available for use. If no mods have dependencies, mod loading order goes in reverse alphabetical order ^(undocumented)^.

## Required dependencies
Required dependencies need to be resolved for a mod to be allowed. You can always rely on these depending mods to exist. In recent versions of Minetest, the game will refuse to load if a player attempts to load a mod with unresolved required dependencies. If your mod gets installed from the main menu content browser, it will attempt to also download required dependencies.

## Optional dependencies
Optional dependencies can be used to provide additional functionality if a mod exists. If you want to use API functions of the mod, you will need to check if the mod exists using `minetest.get_modpath` (it will return nil if the mod isn't loaded).

```lua
if minetest.get_modpath('optionally_dependant_mod') then
    -- Code for when optionally_dependant_mod exists
end
```

## Game Support
In order to support several games, you would want to optionally depend on each game's specific mods. For example:

```lua
if minetest.get_modpath("default") then
    -- Code path for Minetest Game
elseif minetest.get_modpath("mcl_core") then
    -- Code path for MineClone 2
end
```