Can only register ProcessReceipt callback on server

What the message means

Players.Builderman.PlayerGui.Shop.BuyCoins.LocalScript:12: Can only register ProcessReceipt callback on server

Other forms of the same message:

• BindReceiptHandler can only be called from the server

Until a receipt is answered with Enum.ProductPurchaseDecision.PurchaseGranted, Roblox treats the purchase as not delivered and tries again later, for example when the player next joins. A receipt handler that never runs, because it was set in a LocalScript, means players pay and get nothing in that session.

The PromptProductPurchaseFinished event on the client only says the purchase window closed. Do not give items from it: the server receipt is the only reliable signal.

Causes and fixes

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

• The shop button's LocalScript handles the receipt
• A shared module in ReplicatedStorage sets it, and a LocalScript requires it

The shop button's LocalScript handles the receipt

It feels natural to keep the prompt and the reward together in the button's script. The prompt part is allowed there; the receipt part is not.

local MarketplaceService = game:GetService("MarketplaceService")
local Players = game:GetService("Players")

local COINS_PRODUCT_ID = 0000000 -- your developer product ID
local button = script.Parent :: TextButton

button.Activated:Connect(function()
	MarketplaceService:PromptProductPurchase(Players.LocalPlayer, COINS_PRODUCT_ID)
end)

-- Can only register ProcessReceipt callback on server
MarketplaceService.ProcessReceipt = function(_receiptInfo)
	return Enum.ProductPurchaseDecision.PurchaseGranted
end

Delete the receipt part from the LocalScript, keep only the prompt, and handle receipts in a server Script like the one below.

local MarketplaceService = game:GetService("MarketplaceService")
local Players = game:GetService("Players")

local COINS_PRODUCT_ID = 0000000 -- your developer product ID

local function grantCoins(player: Player): boolean
	local leaderstats = player:FindFirstChild("leaderstats")
	local coins = leaderstats and leaderstats:FindFirstChild("Coins")
	if coins and coins:IsA("IntValue") then
		coins.Value += 100
		return true
	end
	return false -- not ready yet: Roblox will try this receipt again later
end

MarketplaceService.ProcessReceipt = function(receiptInfo: { [string]: any }): Enum.ProductPurchaseDecision
	local player = Players:GetPlayerByUserId(receiptInfo.PlayerId)
	if player and receiptInfo.ProductId == COINS_PRODUCT_ID then
		local ok, granted = pcall(grantCoins, player)
		if ok and granted == true then
			return Enum.ProductPurchaseDecision.PurchaseGranted
		end
	end
	return Enum.ProductPurchaseDecision.NotProcessedYet
end

This is the smallest working handler. For a real game, record each PurchaseId in a data store together with the grant, so a receipt delivered twice is never granted twice: the developer products guide builds that version step by step.

A shared module in ReplicatedStorage sets it, and a LocalScript requires it

A Shop ModuleScript in ReplicatedStorage that both the client and the server require runs its top-level code on whichever side requires it. If it sets ProcessReceipt at the top, the client's copy fails.

local MarketplaceService = game:GetService("MarketplaceService")

local Shop = {}
Shop.COINS_PRODUCT_ID = 0000000

function Shop.prompt(player: Player)
	MarketplaceService:PromptProductPurchase(player, Shop.COINS_PRODUCT_ID)
end

-- runs on the client too when a LocalScript requires this module:
-- Can only register ProcessReceipt callback on server
MarketplaceService.ProcessReceipt = function(_receiptInfo)
	return Enum.ProductPurchaseDecision.NotProcessedYet
end

return Shop

Keep shared modules free of receipt code. Shared data (product IDs, prices) can stay in ReplicatedStorage; the receipt handler lives in ServerScriptService and is the only code that sets ProcessReceipt.

local MarketplaceService = game:GetService("MarketplaceService")

local Shop = {}
Shop.COINS_PRODUCT_ID = 0000000

function Shop.prompt(player: Player)
	MarketplaceService:PromptProductPurchase(player, Shop.COINS_PRODUCT_ID)
end

return Shop

Only one script should set ProcessReceipt. Setting it again from another server Script silently replaces the first handler, so products handled there stop being granted.

How to find the line that causes it

1. The path in the message names the script. A path through PlayerGui, PlayerScripts or a character means a LocalScript.
2. Search your place for ProcessReceipt and BindReceiptHandler with Ctrl+Shift+F (Find All). There should be exactly one place that sets it, in ServerScriptService.

Questions

Sources and further reading

• Roblox Creator Docs: MarketplaceService.ProcessReceipt. server only, and the decisions it returns
• Roblox Creator Docs: Developer products
• Roblox Creator Docs: MarketplaceService:PromptProductPurchase

How the code was checked: every block marked Fixed passes Luau's strict type checker against Roblox's API definitions (luau-lsp, 5 November 2026), and every block marked Breaks compiles and fails only when it runs. The message wording was checked against the message strings in Roblox Studio itself (macOS build installed 2 November 2026) and the MarketplaceService reference on 5 November 2026. A type check catches misspelt APIs and wrong types, not game logic, so playtest in Studio before you publish.