Anyone Know How To Save Leaderstats? (i have api thing on)

Let's start over with the Services. We only need 1 Service: DatastoreService. and RunService, if you want to.

DatastoreServices is a Roblox Built-in service designed to save player data, it is advised to have a basic understanding of Roblox Lua before operating with DatastoreService since it could be confusing at times. There are a few alternatives to DatastoreService, of course, if you want to be more advanced with your data saving; like Datastore2, ProfileService, etc.

Let's get onto the code:

local Players = game:GetService("Players")
local DSS = game:GetService("DataStoreService")
local RunService = game:GetService("RunService")

local Data = DSS:GetDataStore("CurrencyData")

Players.PlayerAdded:Connect(function(plr)
	
	local Key = plr.UserId.."Data" -- It is recommended to use the plr.UserId
	
	local leaderstats = Instance.new("Folder")
	leaderstats.Name = "leaderstats"
	leaderstats.Parent = plr
	
	local Clicks = Instance.new("IntValue")
	Clicks.Name = "Clicks"
	Clicks.Value = 0
	Clicks.Parent = leaderstats

	local Rebirths = Instance.new("IntValue")
	Rebirths.Name = "Rebirths"
	Rebirths.Value = 0
	Rebirths.Parent = leaderstats

	local Coins = Instance.new("IntValue")
	Coins.Name = "Coins"
	Coins.Value = 0
	Coins.Parent = leaderstats

	local Gems = Instance.new("IntValue")
	Gems.Name = "Gems"
	Gems.Value = 0
	Gems.Parent = leaderstats
	
	task.wait()
	
	local Loaded, Value, Error = pcall(function() -- // Always use pcall if you're doing an Async
		return Data:GetAsync(Key)
	end)
	
	if Loaded then
		if Value then
			print("Successfully loaded data")
			Clicks.Value = Value[1]
			Rebirths.Value = Value[2]
			Coins.Value = Value[3]
			Gems.Value = Value[4]
		end
	else
		if Error == nil then
			print("System failed to load data due to an unknown reason")
		else
			print("System failed to load data")
			warn(Error)
		end
	end
	
end)

Players.PlayerRemoving:Connect(function(plr)
	
	local Key = plr.UserId.."Data"
	local leaderstats = plr.leaderstats
	
	local Saved, Error = pcall(function()
		Data:SetAsync(Key, {leaderstats.Clicks.Value, leaderstats.Rebirths.Value, leaderstats.Coins.Value, leaderstats.Gems.Value}) -- // Make sure this is in order and consistent with the Data loading part. (If Clicks is set as Value[1], then set it as the first thing in the table.)
	end)
	
	if Saved then
		print("Successfully saved data")
	else
		print("System failed to save data")
		warn(Error)
	end
	
end)

game:BindToClose(function() -- Game is shutting down
	if RunService:IsStudio() then return end
	
	local p = Players:GetPlayers()
	for _, plr in pairs(p) do
		local key = plr.UserId .. "Data" -- Also, make sure the key are consistent with the other keys.
		local leaderstats = plr.leaderstats
		
		local Success, Result = pcall(function()
			Data:SetAsync(key, {leaderstats.Clicks.Value, leaderstats.Rebirths.Value, leaderstats.Coins.Value, leaderstats.Gems.Value})
		end)
		
		if not Success then
			warn(Result)
		end
	end
end)