RemoteEvents — the client asks, the server decides

Two computers are running your game: the player's and the server's. They need to talk. The RemoteEvent is the phone line between them. You've learned why the client must ask the server — now you build the asking.

#The layout

A RemoteEvent lives in a place both sides can see — ReplicatedStorage is the classic home (it exists on both computers, unlike ServerScriptService which the client never sees).

local ReplicatedStorage = game:GetService("ReplicatedStorage")

local coinEvent = Instance.new("RemoteEvent")
coinEvent.Name = "CoinClicked"
coinEvent.Parent = ReplicatedStorage

One object, two directions of phone calls. The client calls the server with :FireServer. The server calls one client with :FireClient or every client with :FireAllClients.

#Client asks (FireServer)

-- LocalScript (on the player's computer)
local ReplicatedStorage = game:GetService("ReplicatedStorage")
local coinEvent = ReplicatedStorage.CoinClicked

coinEvent:FireServer()

That's the whole ask: "hey server, I clicked." No coins here. The client just reports the click. The power to give coins lives entirely on the server.

#Server decides (OnServerEvent)

-- Script (on the server)
local ReplicatedStorage = game:GetService("ReplicatedStorage")
local coinEvent = ReplicatedStorage.CoinClicked

coinEvent.OnServerEvent:Connect(function(player)
    local coins = player.leaderstats.Coins
    if coins then
        coins.Value = coins.Value + 10
    end
end)

OnServerEvent hands you the player who fired — the server never has to guess who's asking. The client reports, the server verifies (the if coins check) and decides.

#Server sends back (FireClient / FireAllClients)

The server needs to tell clients things too — "your UI should update", "the round ended".

-- to a specific player
coinEvent:FireClient(player, newCoins)

-- to everyone
coinEvent:FireAllClients("round over")

And on the client side, you receive:

-- LocalScript
coinEvent.OnClientEvent:Connect(function(message)
    print("The server says: " .. message)
end)

Any values you pass after the target get delivered to the other side. This is the full bridge: client fires up, server fires down.

-- send newCoins to one player

#The full secure coin flow

1. Client: the player clicks the coin → LocalScript fires FireServer().
2. Server: OnServerEvent fires → verifies → adds 10 coins.
3. Leaderboard: the NumberValue updates and everyone sees it.

The client never once told the server "give me coins." It said "I clicked," and the server decided what that click was worth. That's the pattern to copy for every reward in your game.

• Common mistakes
• Putting reward logic in the LocalScript. If the click handler gives coins, it's on the player's machine — exploitable. The LocalScript only reports.
• Parenting the RemoteEvent to ServerScriptService. The client can't see it there, so it can't fire it. ReplicatedStorage is the shared home.
• Trusting values the client sends. "Give me 999 coins" as an argument is a request, not a fact.
• Firing without a handler. Nothing listening on the other end means nothing happens.

Next section: putting all of this to work in a real game — Game Systems.