Setting up a roblox anti cheat script fly speed jump logic is usually the first thing on a developer's to-do list after they realize that, unfortunately, not everyone plays fair. If you've spent any time at all developing on the platform, you've likely seen it happen: a player joins your game, and within thirty seconds, they're zooming across the map like a rocket, jumping over mountains, or just hovering in the air like they've suddenly switched to a creative mode you never built. It's annoying, it ruins the experience for regular players, and if you don't handle it early, it can completely tank your game's retention rates.
The reality of Roblox is that it's an engine where the client (the player's computer) has a lot of say in how their character moves. This is great for responsiveness—nobody wants to wait for a server response just to take a step forward—but it's a massive "kick me" sign for exploiters. Because the client controls their own HumanoidRootPart, they can easily use third-party executors to tell the game, "Hey, I'm actually moving at 500 studs per second now," and the server just sort of nods and goes along with it. That's where your custom script comes in.
Why You Can't Just Trust the Humanoid
You might think, "Can't I just check if their WalkSpeed is higher than 16?" Well, I wish it were that simple. When an exploiter changes their speed or jump power, they're doing it on their local machine. Because of the way Roblox handles physics replication, those changes aren't always visible if you're just checking the property values on the server. The server still thinks their WalkSpeed is 16, even while they're breaking the sound barrier.
This is why a solid roblox anti cheat script fly speed jump needs to rely on server-side position checks rather than just looking at variable numbers. You have to measure what they are actually doing in the 3D space, not what their character sheet says they're doing.
Cracking Down on Speed Hacks
To catch a speed hacker, you need to become a bit of a math nerd, but only for a second. The basic logic is simple: Distance = Speed × Time. If you know how much time has passed since your last check, and you know how far the player moved, you can figure out if they're moving faster than your game's max allowed speed.
In your script, you'll want to run a loop (maybe every second or so) that records the player's position. On the next tick, you compare the new position to the old one. If the distance between those two points is way higher than it should be, you've caught them. However, you've got to be careful with things like teleporters or vehicles. If your game has a "fast travel" button, your anti-cheat is going to think the player is cheating unless you add a way to "whitelist" that specific movement. Usually, a simple boolean (true/false) value on the player can tell the script to ignore them for a second while they're being moved by the game itself.
Dealing with the "Fly" and "Infinite Jump" Issues
Flying is a bit trickier than speed because players are supposed to be in the air sometimes. They jump, they fall, or they might get launched by an explosion. A basic roblox anti cheat script fly speed jump needs to differentiate between a player who is falling gracefully and a player who is just chilling 50 feet in the air.
One of the best ways to handle this is by checking the player's FloorMaterial. If their material is "Air" for more than, say, 5 seconds, and their Y-axis (altitude) isn't decreasing, something fishy is going on. Exploiters often use "BodyVelocity" or "Anchoring" to stay airborne. By tracking how long a player has been "falling" without actually losing height, you can pretty easily identify a fly hack.
For infinite jumping, you can look at the StateChanged event of the Humanoid. If a player triggers a "Jumping" state while they're already mid-air and don't have a double-jump power-up, that's a red flag. Again, don't be too aggressive—Roblox physics can be janky, and sometimes a player might just clip off a ledge and trigger a weird state.
The Nightmare of Latency and False Positives
This is the part that keeps developers up at night. If you make your roblox anti cheat script fly speed jump too strict, you're going to start kicking players who just have bad internet. We've all been there—your ping spikes to 800, you walk forward, and suddenly you're rubber-banding all over the place. To the server, that looks like you just teleported.
To avoid being "that dev" who kicks half their player base, you need to build in a "buffer" or a "strike system." Instead of instantly kicking someone for a single speed violation, give them a "violation point." If they get five points in a minute, then you take action. Also, instead of a flat-out ban, try "rubber-banding" them back to their last known good position. It's much less frustrating for a laggy player to be pulled back a few studs than it is to be kicked from the game entirely and lose their progress.
Server-Side vs. Client-Side: The Golden Rule
If there is one thing you take away from this, let it be this: Never trust the client. You can write the most sophisticated anti-cheat script in the world, but if it's sitting in StarterPlayerScripts, an exploiter can just delete it. It's like putting a lock on a door but giving the burglar the key.
Your primary roblox anti cheat script fly speed jump logic must live in ServerScriptService. The server is the ultimate authority. While you can have a client-side script to catch the "lazy" exploiters who don't know how to disable it, the server-side check is your real line of defense. It's harder for the server to do this because it has to handle multiple players at once, so you have to optimize your code. Don't run checks every single frame; once every 0.5 to 1.0 seconds is usually plenty to catch a cheater without lagging the server into oblivion.
Keeping the Script Updated
The world of Roblox exploits is a bit of a cat-and-mouse game. As soon as developers find a new way to block a fly script, someone figures out a way to bypass it using a new method of physics manipulation. You can't just "set it and forget it."
Check your server logs. If you see your anti-cheat is constantly "tripping" for everyone, it's probably too sensitive. If you see players flying around and the script isn't doing anything, it's time to tighten the screws. Look at how your game's specific mechanics—like pets, tools, or vehicles—interact with the character's physics. Sometimes, a cool new feature you added might accidentally look like a cheat to your own script.
Final Thoughts
At the end of the day, building a roblox anti cheat script fly speed jump system is about balance. You want to protect the integrity of your game without ruining the fun for people with slow computers. It takes a bit of testing and a lot of tweaking, but seeing your game run smoothly without exploiters ruining the vibe is well worth the effort.
Start small. Build a script that just checks for extreme speed first. Once that's working and you've ironed out the bugs, add the height checks for flying. Before you know it, you'll have a solid defense system that lets you focus on the fun stuff—like actually building your game—instead of constantly playing moderator. Happy developing, and keep those hackers at bay!