diff --git a/mods/CORE/mcl_worlds/API.md b/mods/CORE/mcl_worlds/API.md
new file mode 100644
index 0000000000..a5509431c2
--- /dev/null
+++ b/mods/CORE/mcl_worlds/API.md
@@ -0,0 +1,80 @@
+# mcl_worlds
+This mod provides utility functions about positions and dimensions.
+
+## mcl_worlds.is_in_void(pos)
+This function returns:
+
+* true, true: if pos is in deep void (deadly)
+* true, false: if the pos is in void (non deadly)
+* false, false: owerwise
+
+Params:
+
+* pos: position
+
+## mcl_worlds.y_to_layer(y)
+This function is used to calculate the minetest y layer and dimension of the given <y> minecraft layer.
+Mainly used for ore generation.
+Takes an Y coordinate as input and returns:
+
+* The corresponding Minecraft layer (can be nil if void)
+* The corresponding Minecraft dimension ("overworld", "nether" or "end") or "void" if <y> is in the void
+If the Y coordinate is not located in any dimension, it will return: nil, "void"
+
+Params:
+
+* y: int
+
+## mcl_worlds.pos_to_dimension(pos)
+This function return the Minecraft dimension of <pos> ("overworld", "nether" or "end") or "void" if <y> is in the void.
+
+* pos: position
+
+## mcl_worlds.layer_to_y(layer, mc_dimension)
+Takes a Minecraft layer and a “dimension” name and returns the corresponding Y coordinate for MineClone 2.
+mc_dimension can be "overworld", "nether", "end" (default: "overworld").
+
+* layer: int
+* mc_dimension: string
+
+## mcl_worlds.has_weather(pos)
+Returns true if <pos> can have weather, false owerwise.
+Weather can be only in the overworld.
+
+* pos: position
+
+## mcl_worlds.has_dust(pos)
+Returns true if <pos> can have nether dust, false owerwise.
+Nether dust can be only in the nether.
+
+* pos: position
+
+## mcl_worlds.compass_works(pos)
+Returns true if compasses are working at <pos>, false owerwise.
+In mc, you cant use compass in the nether and the end.
+
+* pos: position
+
+## mcl_worlds.compass_works(pos)
+Returns true if clock are working at <pos>, false owerwise.
+In mc, you cant use clock in the nether and the end.
+
+* pos: position
+
+## mcl_worlds.register_on_dimension_change(function(player, dimension))
+Register a callback function func(player, dimension).
+It will be called whenever a player changes between dimensions.
+The void counts as dimension.
+
+* player: player, the player who changed the dimension
+* dimension: position, The new dimension of the player ("overworld", "nether", "end", "void").
+
+
+## mcl_worlds.registered_on_dimension_change
+Table containing all function registered with mcl_worlds.register_on_dimension_change()
+
+## mcl_worlds.dimension_change(player, dimension)
+Notify this mod of a dimmension change of <player> to <dimension>
+
+* player: player, player who changed the dimension
+* dimension: string, new dimension ("overworld", "nether", "end", "void")
\ No newline at end of file