attempt to call a nil value

What the message means

ServerScriptService.Shop:14: attempt to call a nil value

Other forms of the same message:

• attempt to call missing method 'GiveCoins' of table

When Luau reaches giveCoins(player), it looks up giveCoins, then calls it. If the lookup found nothing, the value is nil, and calling nil is this error. Luau cannot tell you the name you meant, so the message stays short.

Roblox objects are different: calling a method that an Instance does not have, such as part:Destroyy(), fails with Destroyy is not a valid member of Part instead.

Causes and fixes

Four things cause this error in practice. Each one below has the smallest code that triggers it, then the fix.

• The name is misspelt or has different capitals
• The function is defined below the line that calls it
• A ModuleScript does not put the function in its table
• A method is called with a colon but defined with a dot, or is missing

The name is misspelt or has different capitals

Luau names are case-sensitive: givecoins, GiveCoins and giveCoins are three different names. A name that was never defined reads as a global that is nil.

local function giveCoins(player, amount)
	print(player, amount)
end

-- capital G: this name was never defined
GiveCoins("Builderman", 10)

Use the exact name the function was defined with. The Script Editor underlines an unknown name in orange (Unknown global) before you even press Play, so look for that underline.

local function giveCoins(playerName: string, amount: number)
	print(playerName, amount)
end

giveCoins("Builderman", 10)

The function is defined below the line that calls it

A local function exists only from its own line down. Code above it cannot see it, so the name there means a global that is nil. It works in some scripts only because the call happens later, inside an event.

-- runs before the function below exists
setUpShop()

local function setUpShop()
	print("shop ready")
end

Define functions at the top of the script and call them at the bottom. If two functions call each other, declare the name first with local name, then assign it.

local function setUpShop()
	print("shop ready")
end

setUpShop()

A ModuleScript does not put the function in its table

Other scripts only see what a ModuleScript returns. A function made with local function inside the module, and never added to the returned table, is nil to everyone else.

local Shop = {}

local function buy(itemName)
	print("bought", itemName)
end

return Shop
-- in another script: require(Shop).buy("Sword") -> attempt to call a nil value

Add the function to the table the module returns, then call it through that table.

local Shop = {}

function Shop.buy(itemName: string)
	print("bought", itemName)
end

return Shop

Then require(ReplicatedStorage.Shop).buy("Sword") works from any script that can see ReplicatedStorage.

A method is called with a colon but defined with a dot, or is missing

Shop:buy() looks up buy on Shop and passes Shop as the first argument. If the table has no buy, the message is attempt to call missing method 'buy' of table. If it has one defined with a dot, the call works but every argument shifts by one place.

local Shop = {}

function Shop.Buy(itemName)
	print("bought", itemName)
end

-- the table has Buy, not buy: attempt to call missing method 'buy' of table
Shop:buy("Sword")

Match the name exactly, and match how it is defined: a function defined with . is called with ., one defined with : is called with :.

local Shop = {}

function Shop.Buy(itemName: string)
	print("bought", itemName)
end

Shop.Buy("Sword")

How to find the line that causes it

1. Open Output (Window menu, or the Script tab), clear it with Ctrl+K (⌘K on Mac), and press Play.
2. Find the first red line. It starts with the script's place in the Explorer and the line number, such as ServerScriptService.Shop:12:.
3. Click the red line. Studio opens that script with the cursor on the failing line.
4. Read the lines between Stack Begin and Stack End under it: they list the calls that led there, newest first, so you can see which function called the broken one.
5. Still not sure which value is wrong? Add print(typeof(x), x) just above the line, or set a breakpoint on it and read the values in the Watch window.

Questions

Sources and further reading

• Roblox Creator Docs: functions
• Roblox Creator Docs: ModuleScript
• Luau: syntax

How the code was checked: every block marked Fixed passes Luau's strict type checker against Roblox's API definitions (luau-lsp, 23 October 2026), and every block marked Breaks compiles and fails only when it runs. The message wording was checked by running the broken code with the Luau command line tool and against the message strings in Roblox Studio itself on 23 October 2026. A type check catches misspelt APIs and wrong types, not game logic, so playtest in Studio before you publish.