If you're starting to build your first game, figuring out roblox local script vs server script logic is usually the first major hurdle you'll face. You've probably written a bit of code that works perfectly in your head, but when you hit play, nothing happens—or worse, it only works for you and no one else in the game. It's a frustrating rite of passage for every developer on the platform.
The core of the issue is that Roblox isn't just running on your computer; it's a multiplayer environment where a central computer (the server) has to keep everyone on the same page. If you don't know which script to use for which task, your game is going to feel broken, buggy, or wide open to exploiters. Let's break down how these two script types actually work and how to choose between them without getting a headache.
The Server Script: The Source of Truth
In the Roblox world, the server script (usually just called a "Script" in the Explorer) is the boss. It lives on Roblox's cloud servers, not on the player's phone or laptop. Think of it as the "Source of Truth." If the server says a part is red, then for every single person in that game, that part is red.
Server scripts are responsible for the heavy lifting that affects the whole game world. If you're making a lava part that kills players, you want that to be a server script. Why? Because you don't want the player's computer to decide if they're dead or not; you want the server to make that call so people can't just delete the "kill script" on their end and become immortal.
You'll usually find these scripts sitting inside ServerScriptService or tucked away inside parts in the Workspace. They handle things like: * Saving player data (like levels or gold). * Giving items to players. * Changing the game state (starting a round, ending a match). * Handling leaderboards. * Damaging or healing characters.
The big thing to remember is that server scripts can't see things that only exist on a single player's screen. They don't know where your mouse is pointing, and they don't know if you've clicked a button on your screen's menu.
The Local Script: The Player's Perspective
Now, the LocalScript is a bit different. This script runs on the "Client," which is just a fancy way of saying it runs on the player's specific device. If a LocalScript changes something—like the color of a wall—that change only happens for that one player. Everyone else in the game will still see the original color.
This might sound like a limitation, but it's actually essential. You don't want the entire server to lag every time a player moves their camera or hovers their mouse over a button. Local scripts handle the "feel" of the game. They are responsible for: * User Interface (UI): Opening menus, health bars, and inventory screens. * Input: Detecting when you press the "E" key, click your mouse, or move a joystick. * Camera movements: Any custom camera angles or cutscenes. * Sounds and Visual Effects: Stuff like screen shakes or footprints that only that player needs to see to keep the game running smoothly.
Local scripts usually live in places like StarterPlayerScripts, StarterCharacterScripts, or inside ScreenGuis. If you put a LocalScript in ServerScriptService, it simply won't run. It needs to be somewhere "owned" by the player.
Why the distinction exists (Security 101)
You might wonder why we can't just do everything in one script type. A long time ago, Roblox was a bit more "open," and what happened on the client often happened on the server too. But that made it incredibly easy for hackers to ruin games. A player could run a script on their own computer that said "give everyone 1,000,000 gold," and the server would just believe them.
Nowadays, Roblox uses something called FilteringEnabled. This is a safety wall. It ensures that if a player's local script tries to do something suspicious to the game world, the server ignores it. This is why when you're testing your game and you delete a wall while in "Client" mode, the wall is still there for everyone else.
Understanding the roblox local script vs server script divide is essentially learning how to work with this security wall. You use LocalScripts for the player's personal experience and ServerScripts to make sure the game stays fair and synchronized.
The Bridge: RemoteEvents
So, if LocalScripts can't change the world and ServerScripts can't see your mouse clicks, how do you actually make a game? If I click a "Buy" button on my UI (LocalScript), how does the server know to take my gold (ServerScript)?
This is where RemoteEvents come in. Think of a RemoteEvent as a walkie-talkie. 1. The LocalScript "fires" the event: "Hey Server, this player clicked the buy button!" 2. The ServerScript "listens" for the event: "Oh, someone wants to buy something? Let me check if they have enough gold. If they do, I'll subtract the gold and give them the item."
Without RemoteEvents, the two types of scripts are basically living in different dimensions. You need that bridge to allow them to communicate. But be careful—never trust the client. If your RemoteEvent says "Set my gold to 999," a hacker will find that event and abuse it. Instead, your event should just say "I want to buy this," and the server should do all the math and checking.
Common Scenarios: Which one do I use?
It can still be a little confusing when you're staring at the Explorer window. Here are a few common situations and the "right" script for the job:
1. A Shop System * LocalScript: Detects when the player clicks the "Shop" button on their screen and opens the menu. * RemoteEvent: Sends a message when the player clicks "Purchase." * ServerScript: Receives that message, checks the player's currency, and grants the item.
2. A Proximity Prompt (Door) * ServerScript: Since you want the door to open for everyone, you generally handle the ProximityPrompt's "Triggered" signal in a server script.
3. Footstep Sounds * LocalScript: You don't necessarily need the server to play every single footstep sound for every player (that's a lot of network traffic). You can have a LocalScript play sounds for the player themselves to keep things snappy.
4. A Tool (Sword or Gun) * LocalScript: Detects the mouse click to "fire" or "swing" so there's no delay for the player. * ServerScript: Actually deals the damage to the enemy so players can't cheat and kill people from across the map.
Where to put your scripts
Placement is half the battle. If your script is in the wrong folder, it won't run, and you'll spend three hours debugging nothing.
ServerScripts belong in:
- ServerScriptService: Best place for general game logic.
- Workspace: Only if the script is inside a specific part or model (like a kill brick).
LocalScripts belong in:
- StarterPlayerScripts: For things that run as soon as the player joins.
- StarterCharacterScripts: For things that reset every time the player's character spawns (like movement boosts).
- StarterGui: For anything related to buttons, health bars, or menus.
Final Thoughts on Script Choice
Don't feel bad if you get these mixed up at first. Even experienced developers occasionally write UI logic in a server script and wonder why the button doesn't click. The golden rule is: Local is for the eyes, Server is for the prize.
If it's about what the player sees, feels, or presses, go Local. If it's about points, health, parts moving for everyone, or data being saved, go Server. Once you get the hang of using RemoteEvents to link the two, you'll find that the roblox local script vs server script distinction isn't a hurdle—it's actually the framework that makes your game secure and functional. Keep practicing, and eventually, choosing between them will become second nature.