If you're trying to make your game feel responsive and professional, you really need to get comfortable with the roblox studio run service heartbeat event. It's one of those fundamental tools that separates a clunky, stuttering project from something that actually feels smooth to play. Most new developers start out using while true do wait(), but that's a habit you'll want to break pretty quickly if you care about performance and precision.
The Heartbeat event is part of the RunService, and it fires every single frame after the physics simulation has completed. Because it's tied to the frame rate of the engine, it's much more reliable than a standard wait() loop. Whether you're moving a platform, checking distances between players, or updating a custom UI element, this is often the tool for the job.
What exactly is Heartbeat?
To understand Heartbeat, you first have to visualize the "frame cycle" in Roblox. Every second, the engine is doing a million things: it calculates where parts are moving, checks for collisions, runs your scripts, and finally renders the image to your screen.
RunService.Heartbeat happens right at the end of that cycle, after the physics have already been calculated. This makes it perfect for logic that needs to happen constantly but doesn't necessarily need to interfere with how a part is physically bumping into another part. It's worth noting that Heartbeat runs on both the server and the client, which gives it a lot of versatility compared to other events like RenderStepped.
Why you should stop using wait()
We've all been there—writing a while true do wait() loop because it's the easiest way to make something repeat. But here's the problem: wait() is notoriously imprecise. If the server is lagging or if there's a lot of traffic, that wait() might take longer than you intended. It also has a minimum cap (usually around 0.03 seconds), which means you can't use it for things that need to happen every single frame.
When you use the roblox studio run service heartbeat, you're hooking your code directly into the engine's pulse. It's cleaner, it's faster, and it's much more predictable. If your game is running at 60 frames per second, Heartbeat is firing 60 times a second. If you're on a high-refresh-rate monitor running at 144 FPS, it fires 144 times. It scales with the hardware, which is exactly what you want.
The importance of DeltaTime
One of the coolest things about Heartbeat is that it passes a variable to your function called step or deltaTime. This value represents the exact amount of time that has passed since the last frame.
Why does this matter? Well, imagine you're moving a part 1 stud every frame. If a player has a slow computer running at 30 FPS, the part moves 30 studs in a second. If another player has a beastly PC running at 120 FPS, that same part moves 120 studs in a second! That's a huge problem for game balance.
By multiplying your movement by deltaTime, you make your movement "frame-rate independent." This ensures that the part moves at the same speed regardless of how fast or slow the user's computer is. It's a small detail that makes a massive difference in how professional your game feels.
A quick code example:
```lua local RunService = game:GetService("RunService") local part = script.Parent local speed = 10
RunService.Heartbeat:Connect(function(dt) part.CFrame = part.CFrame * CFrame.new(0, 0, -speed * dt) end) `` In this snippet,dtis our delta time. Multiplying the speed bydt` ensures the part moves 10 studs per second, no matter what the frame rate is.
Heartbeat vs. RenderStepped vs. Stepped
This is where things can get a little confusing for beginners. RunService actually has three main events you'll see people talk about, and picking the right one is important.
- Heartbeat: Fires after physics. Good for almost everything, especially on the server.
- Stepped: Fires before physics. Use this if you're doing something that needs to influence how parts collide or move in the current frame's physics step.
- RenderStepped: Fires before a frame is rendered. This is client-only. You use this for things like custom cameras or UI that needs to look incredibly smooth. However, you shouldn't do heavy math here because it can actually delay the frame from rendering, causing visual lag.
For most general-purpose scripting—like checking if a player is in a certain zone or rotating a coin—roblox studio run service heartbeat is the safest and most efficient choice.
Performance considerations
Just because Heartbeat is powerful doesn't mean you should throw everything into it. Remember, any code inside a Heartbeat connection is running dozens (or hundreds) of times every single second. If you put a heavy for loop or a complex raycast inside a Heartbeat function, you're going to tank your game's performance.
If you have a task that doesn't actually need to happen every frame, don't put it in Heartbeat. For example, if you're checking if a player has enough gold to buy an item, you don't need to check that 60 times a second. A simple event-based system or a slower loop is much better for that. Use Heartbeat for things that require visual smoothness or high-frequency updates.
Managing your connections
A common mistake I see developers make is "firing and forgetting" their connections. Every time you call :Connect() on Heartbeat, you're telling the engine to keep running that function forever. If you delete the script or the object but don't disconnect the event, you might end up with a memory leak.
It's always a good habit to store your connection in a variable so you can shut it down when it's no longer needed.
lua local connection connection = RunService.Heartbeat:Connect(function(dt) -- Do something cool if conditionMet then connection:Disconnect() -- Clean up after yourself! end end)
Real-world use cases
Let's talk about where you'll actually use this in your games. One of the best uses for roblox studio run service heartbeat is for custom character controllers or hovering vehicles. Since these need to feel "snappy" and responsive to player input, updating their forces or positions every frame is essential.
Another great use is for environmental effects. If you want a subtle bobbing motion for a floating island or a spinning animation for a power-up, Heartbeat (combined with delta time) will give you a silky-smooth result that looks much better than an old-school while loop.
I also use it a lot for "soft" constraints. If you want a part to follow a player but with a little bit of a delay or a "smoothing" effect (using Lerp), Heartbeat is the perfect place to put that logic. You can calculate the new position every frame and move the object incrementally, creating a very polished feel.
Final thoughts
Getting the hang of the roblox studio run service heartbeat is a bit of a rite of passage for Roblox devs. It moves you away from "beginner" scripting patterns and into the world of optimized, professional game design. It might feel a bit more complex than a simple wait() at first, especially when you start factoring in delta time, but the results speak for themselves.
Next time you're about to write a loop that needs to be fast, give Heartbeat a try instead. Your players (and their frame rates) will thank you for it. Just remember to keep your code inside the function as light as possible and always use that delta time argument to keep things consistent. Happy scripting!