If you want your FiveM server to hold more than a handful of players, you need to understand OneSync. It’s the system that controls how many players your server supports and how the world stays synchronised between them. This guide explains OneSync, player slots, and how to set them correctly.
What is OneSync?
OneSync is FiveM’s server-side state synchronisation system. The original GTA networking model topped out at 32 players; OneSync raised that ceiling dramatically and improved how entities (vehicles, peds, objects) sync across everyone on the server. Without OneSync you’re capped at 32; with it, you can run the large roleplay servers FiveM is known for.
Legacy OneSync vs OneSync Infinity
- Legacy OneSync — supports up to 64 slots with improved entity sync.
- OneSync Infinity — the modern evolution, supporting 128+ concurrent players with advanced entity synchronisation and better performance at scale. Enable it with
onesync_enableInfinity 1for 64+ player servers.
Setting your player slots (sv_maxclients)
Player count is set with sv_maxclients in your server.cfg. Two rules to know:
- It should be a power of 2 — recommended values are 32, 64, 128 or 256.
- For 64+ players, enable OneSync Infinity (
onesync_enableInfinity 1).
The 48-slot subscription requirement
This trips up a lot of new server owners: running more than 48 slots requires a Cfx.re Element Club (Argentum or higher) subscription tied to your license key. Without it, setting sv_maxclients above 48 will cause your server to fail its heartbeat check and not list properly. If you plan a 64+ player server, budget for the Cfx.re membership alongside your hosting.
Performance: more slots means more load
OneSync — especially Infinity at high player counts — increases CPU and resource usage. A 128-player server does far more simulation work than a 32-player one, and since FiveM is single-thread-bound, that lands on one core. If you scale up slots, scale up your hardware too, and keep your scripts optimised (see our server optimization guide). Managed FiveM hosting on high-clock AMD Ryzen 9 cores gives big servers the single-thread headroom they need.
How to enable OneSync
On managed hosting, OneSync is usually a toggle in your panel or txAdmin. Manually, it’s set in your server.cfg:
set onesync on
set onesync_enableInfinity 1
sv_maxclients 128Set sv_maxclients to your target (a power of 2), enable Infinity for 64+, and restart. Confirm in the console that OneSync started without errors.
OneSync and your scripts
Most modern roleplay frameworks and scripts — ESX, QBCore, QBox and the ox stack — require OneSync and won’t function correctly without it. If you’re following any current RP setup guide, OneSync is assumed to be on. Older, abandoned scripts written for the pre-OneSync era may misbehave, which is another reason to use actively-maintained resources. OneSync also unlocks routing buckets, the feature that powers instanced apartments, interiors and separate sessions — essential for serious RP servers.
Frequently asked questions
How many players can a FiveM server have?
32 without OneSync, up to 64 on legacy OneSync, and 128+ with OneSync Infinity. The hard cap is high (up to 2048), but real capacity depends on your CPU and scripts.
Do I need OneSync for more than 32 players?
Yes — OneSync is required to exceed 32, and OneSync Infinity (onesync_enableInfinity 1) for 64+.
Why won’t my FiveM server go above 48 slots?
Slots above 48 require a Cfx.re Element Club (Argentum+) subscription linked to your license key. Without it the server fails its heartbeat check.
What should sv_maxclients be set to?
A power of 2 — 32, 64, 128 or 256 — matched to your hardware and OneSync setting.
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