The Roblox Require Script: How It Actually Works
Require in Roblox is the standard way one script loads another. That's it. The Roblox Require Script pattern just formalizes this process so you don't end up with scripts duplicating the same code across twenty different places in your project. I've watched people overcomplicate it constantly, probably because they've never properly understood what the underlying function actually does. At its core, require() takes a string reference — usually a ModuleScript's ID — and returns whatever the module's Output variable contains. If your ModuleScript sets Output to a table of functions, require() hands you that table. If it sets Output to nil, you get nil. Simple. The trick is knowing the gotchas that come with it. I spent an afternoon debugging an issue where a ModuleScript was being required inside a LocalScript, but the data wasn't persisting between players in the same session. Turns out the module was firing during player join and creating new instances instead of referencing cached ones. The fix wasn't in the require syntax — it was realizing that each require call on a fresh ModuleScript instance returns a fresh copy of the output table unless you're using the shared module cache properly.
How to Set It Up
Create a ModuleScript anywhere under ServerScriptService, ReplicatedStorage, or wherever makes sense for your architecture. Name it something meaningful — "DamageSystem" not "Module5". Inside, define your functions and assign them to an Output variable at the bottom: Then in your other scripts, you load it once and reuse: Important detail: require() caches results by ModuleScript path. Calling require() ten times with the same path returns the exact same table reference on the eleventh call. That's why you don't re-require inside loops or frequently-called functions — you grab it once at the top and move on.
The first time I hit this one, it cost me about forty minutes I'll never get back. When you require a ModuleScript from both the server and the client side, each side gets its own instance of the module. Changes on the server don't reflect on the client because they're operating on separate copies. If you need cross-sided state, you have to either put shared logic in a remote event handler or structure your require calls so both sides reference the exact same source. Another thing nobody warns you about: circular requires. If Script A requires Script B, and Script B requires Script A, your game will throw a runtime error. I've seen this happen in projects where people split features into separate modules without thinking through the dependency graph. The workaround is to pull the shared pieces into a third module and have both scripts require that one instead. Here's another one that's easy to miss. If your ModuleScript's Output isn't a table but a primitive value — a number, a string, a boolean — and you mutate that value expecting other scripts to see the change, you won't. Tables are references. Numbers and strings are copies. So if you need state that persists across multiple requires, always return a table.
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When Require Isn't The Right Answer
For simple projects with just a handful of scripts, adding a Require Script layer might be overkill. You can stick the logic directly in a regular script and be done with it. The overhead of setting up module structures only pays off when your project grows past roughly ten interconnected scripts. Before that point, you're just adding indirection without any real benefit. If you're building something that needs real-time communication between server and client, a RemoteEvent or BindableEvent approach will serve you better than trying to force everything through require. Modules are great for organizing code. They're not a communication protocol.
Roblox Require Script
The pattern is reliable once you understand the caching behavior and the client-server boundary. Most problems people run into aren't bugs in require itself — they're mistakes in how they structured their modules. Set up a single source of truth per module, avoid circular dependencies, return tables for shared state, and the whole thing tends to hold together without drama.
