Why most FiveM anticheats fail
The single most important idea in FiveM security is this: the client is hostile. Anyone connecting to your server can read, modify, and inject code into the game client running on their own machine. A cheater can dump your client scripts, spoof natives, fake events, and lie about their position, health, and inventory.
This is why a huge share of FiveM anticheats fail. They run detection logic on the client and then trust the client to report cheating honestly. That is like asking a thief to fill out a form confirming they did not steal anything. A determined cheater simply patches out the detection routine, blocks the report event, or feeds it fake data.
Real protection comes from the only place the cheater does not control: your server. The server is the single source of truth. If your server validates state instead of trusting the client, most cheats become useless because the game state the cheater wants to change is never actually owned by the client in the first place.
The principle: server-side authority
Server-side authority means the server decides what is real. The client can request things, but the server confirms or rejects them. Money, inventory, position, and ownership all live server-side, and the client only renders what the server allows.
Concretely, this looks like:
- A player triggers an event to buy a vehicle. The server checks the player actually has the money, deducts it server-side, then grants the car. It never trusts a client message that says "I have $1,000,000."
- A player reports a new position. The server checks the distance moved since the last update. A jump of 500 meters in one frame is physically impossible and gets rejected or flagged.
- A player tries to give themselves an item. The server checks whether the item exists, whether the player is allowed to have it, and whether the source makes sense.
If you build with server authority from the start, you remove entire categories of cheating. Money dupes, item spawning, and god mode all depend on the client being trusted. Take that trust away and the cheat has nowhere to land.
Layer 1: server-side validation
Server-side validation is the foundation. Every state change that matters should be validated on the server before it is committed.
The classic mistake is a client event like TriggerServerEvent('bank:addMoney', amount) where the server blindly adds whatever amount the client sends. A cheater calls that event with a billion. The fix is to never let the client name the amount for a privileged action. The server computes the amount from the action: it knows the job paycheck, the sale price, or the reward, and it applies that value itself.
For positions, the server should sanity check movement. If a player teleports across the map between two updates, that is a flag. For health and armor, the server should track damage events and reject impossible swings. For inventory, the server owns the inventory table and the client only sends intents like "use item slot 3," which the server validates against what that slot actually contains.
Validation does not need to be perfect to be valuable. Even simple bounds checks (no negative money, no item quantities above a cap, no teleport-speed movement) catch the majority of low-effort cheaters.
Layer 2: OneSync entity lockdown
OneSync is the server-side networking model that replaced the old peer-to-peer state. It moves entity ownership and routing to the server, which is what makes meaningful entity protection possible.
OneSync is enabled in your server config with set onesync on, and it unlocks entity lockdown. Entity lockdown is configured with the sv_entityLockdown convar (and can be set per routing bucket at runtime via the SET_ROUTING_BUCKET_ENTITY_LOCKDOWN_MODE native). It controls whether clients are allowed to create entities (vehicles, peds, objects) directly, or whether only the server can. The modes are inactive, relaxed, and strict.
With strict entity lockdown, clients cannot spawn networked entities on their own. A cheater who tries to spam a thousand vehicles to crash your server, or spawn a tank to grief, finds the server refuses to register those entities. Legitimate spawning still works because your resources create entities server-side and the server is allowed to.
This is a powerful layer because it shuts down a large family of griefing and crashing exploits at the networking level, not at the script level. You do not have to detect the cheat. The action is simply not permitted.
Layer 3: event security
Events are the bridge between client and server, and they are the most abused surface in FiveM. A cheater who finds an unprotected server event can trigger admin actions, give themselves money, or kick other players.
Three practices harden events:
- Treat every server event as a public endpoint. Assume any client can call any event with any arguments. Validate the source and the arguments every time.
- Never put privileged logic behind a client-triggerable event without a permission check. An event like
admin:revivePlayermust verify the calling player is actually an admin, server-side, using your ACE permissions or framework roles. - Use event source checking. The
sourcevalue in a server event handler is set by the server, not the client, so it is trustworthy for identifying who fired the event. Use it. Do not pass a player ID as an argument and trust it, because the client can lie about that argument.
Many framework exploits over the years have been unprotected events. Auditing your events, and the events in every third-party resource you install, is one of the highest-value security tasks you can do.
Layer 4: detection tooling and anticheats
The layers above are about prevention. The detection layer is about catching what slips through and reacting fast.
txAdmin ships with the FiveM server and is your baseline operations tool. It is not an anticheat in the cheat-detection sense, but it gives you live player management, action logging, ban management with identifier tracking, and the ability to kick or ban quickly. Good logging through txAdmin and your own scripts is what lets you spot patterns: the same player triggering thousands of events, sudden money spikes, or repeated kicks.
Client-detection anticheats are resources that look for known injectors, modified resources, and common cheat signatures from the client side. These add value as an extra net, but remember the core limitation: anything running client-side can in principle be defeated by a sophisticated cheater. Treat client detection as a deterrent against casual cheaters, not a wall against determined ones.
Paid anticheats in the FiveM ecosystem combine client-side detection, obfuscation, screenshot capture for staff review, and server-side helpers. They raise the cost of cheating and handle a lot of the busy work. They are worth considering for large servers, but they are a complement to server-side authority, not a replacement. A paid anticheat bolted onto a server that trusts the client for money will still get duped.
Putting the layers together
Think of it as defense in depth. Server-side validation removes the value of cheating. OneSync entity lockdown blocks unauthorized entity creation. Event security closes the client-to-server attack surface. Detection tooling catches and punishes what remains.
No layer is sufficient alone, and the order matters. Spend your first effort on validation and event security, because those are free, permanent, and defeat whole cheat categories. Add OneSync lockdown next. Layer detection on top once the foundation is solid. A server built this way is dramatically harder to ruin than one relying on a single anticheat resource.