If you're tired of seeing players zip around your map, setting up a solid roblox anti cheat script fly detection system is probably your top priority right now. There is honestly nothing more frustrating than spending hundreds of hours polishing a game, balancing the mechanics, and building a community, only to have a random exploiter join and start hovering over everyone like some kind of glitchy god. It ruins the immersion, breaks the gameplay loop, and usually makes other players quit out of sheer annoyance.
The thing about Roblox is that it gives the client—the player's computer—a lot of say in how their character moves. This is great for making the game feel responsive even if someone has a bit of lag, but it's a massive open door for people using third-party software. To stop them, we have to get a bit creative with how we track movement on the server side.
Why basic checks often fail
A lot of developers start out by trying to check things on the client side. They'll write a local script that looks for fly hacks and deletes the player if it finds anything. Here's the problem: exploiters can see your local scripts. They can disable them, delete them, or just modify them so they don't do anything. If your roblox anti cheat script fly detection relies on the player's own computer to "report" that they are cheating, you've already lost the battle.
To actually catch someone, the logic has to live on the server. The server is the "source of truth." It doesn't matter what the exploiter's screen says; if the server sees them floating thirty feet in the air for ten seconds straight without a floor under them, it knows something is up. But even on the server, you have to be careful. If you're too strict, you'll end up kicking players who just have a bad internet connection or those who happened to trip over a weird piece of geometry.
The logic behind catching a flyer
When you're building a roblox anti cheat script fly detection setup, you're basically looking for two main things: vertical position and state. Most fly exploits work by overriding the character's velocity or "anchoring" them in the air while allowing them to move horizontally.
A simple way to start is by checking the player's FloorMaterial. If a player is in the air, their FloorMaterial usually switches to Air. Now, jumping is a normal part of the game, so you can't just kick someone the second they aren't touching the ground. You have to track how long they stay in that state. If a player is "falling" or in the "air" state for more than, say, three or four seconds without their altitude decreasing, that's a massive red flag.
Using Raycasting for accuracy
One of the most reliable ways to see if someone is actually flying is through raycasting. You can cast a "ray" (basically an invisible line) from the player's RootPart straight down toward the ground. If that ray travels 50 studs and doesn't hit anything, but the player isn't actively falling downward at a high speed, they are likely hovering.
The reason raycasting is so much better than just checking the player's state is that it's harder to spoof. You can tell the script, "Hey, if the distance to the ground is more than 15 studs, and their vertical velocity is near zero, start a timer." If that timer hits a certain threshold, you trigger a lag-back or a kick.
Handling the "False Positive" nightmare
This is where things get tricky. If you've ever played a game with a "bad" anti-cheat, you know how annoying it is to get teleported back to the ground just because you jumped off a ledge or stepped on a physics-enabled part. High-ping players are the biggest challenge here. Their character might appear to be floating to the server because their movement data is reaching the server in chunks rather than a smooth stream.
To avoid ruining the experience for legitimate players, your roblox anti cheat script fly detection shouldn't be an instant "judge, jury, and executioner." Instead of kicking them immediately, try a "violation level" system.
Every time the script thinks a player is flying, it adds a point to their "suspicion" score. If they land on the ground, that score slowly ticks back down to zero. If the score hits a limit (let's say 5 violations in 10 seconds), then you take action. You could start by just teleporting them back to their last known "safe" position on the ground. If they keep triggering it, then you go for the kick or the ban. This approach is much more forgiving for people with laggy Wi-Fi.
Dealing with legit gameplay mechanics
Think about your game's specific mechanics before you finalize your script. Do you have vehicles? Do you have knockback weapons? Do you have trampolines or gravity coils? All of these things will look like "flying" to a basic script.
If your game has a double-jump mechanic, your roblox anti cheat script fly detection needs to be aware of that. You might need to add a "grace period" whenever a player uses a legitimate movement ability. For instance, if a player hits a jump pad, you can tag that player with an attribute like IsJumping = true for two seconds. The anti-cheat script should check for that attribute and ignore the player while it's active.
The importance of server-side velocity checks
Another trick exploiters use is modifying their AssemblyLinearVelocity. They might not be "flying" in the traditional sense, but they might be gliding or moving upwards slowly. By monitoring the Y axis of their velocity, you can catch people who are clearly defying gravity.
A normal player falling should have a negative Y velocity that increases (getting more negative) until they hit terminal velocity or the ground. A flyer will often have a Y velocity of exactly 0 or a very small positive number while they are high in the air. Checking for this "gravity-defying" velocity is a great way to bolster your detection.
Putting it all together
When you actually sit down to write the code, keep it efficient. You don't want to run a complex raycast and velocity check on every single player 60 times a second. That's a fast track to server lag. Instead, run your checks in a loop every 0.5 or 1 second. That's more than enough time to catch a flyer before they do too much damage, and it keeps your server's heart rate down.
You should also keep a "last safe position" variable for every player. Every time the server confirms a player is touching the ground, update this variable. If your roblox anti cheat script fly detection catches them in the air, you don't have to kick them—you can just set their character's CFrame back to that last safe position. It's a very effective way to stop exploiters in their tracks without making a permanent mistake against a laggy player.
Keep it updated
The battle against exploiters is never really over. People who make cheats are always looking for ways around the latest scripts. They might find a way to fake their velocity or trick the server into thinking they are constantly "tripping" so the fly check doesn't trigger.
The best thing you can do is keep your roblox anti cheat script fly detection flexible. Don't just set it and forget it. Watch your server logs. If you see a bunch of players getting kicked at the same spot in your map, go check it out—there might be a hole in the floor or a weird invisible part that's triggering the anti-cheat.
At the end of the day, no anti-cheat is perfect. Your goal isn't to make an impenetrable fortress (though that would be nice), it's to make it so difficult and annoying to cheat in your game that the exploiters just give up and go somewhere else. By focusing on server-side logic, using raycasts wisely, and accounting for lag, you'll be miles ahead of most developers and well on your way to a cleaner, fairer game environment.