How do I prevent desync in my multiplayer game?

Establish a single source of truth and keep clients reconciled to it despite the unreliable network. Make the server or host authoritative over important state, with clients reconciling to it rather than computing state independently and drifting apart, since desync at its root is clients diverging without a single source of truth, authoritative state prevents that divergence. Handle the network's unreliability robustly, since even with authoritative state, late, lost, and out-of-order messages can cause clients to drift from the truth, so account for late and missing updates, reconcile clients back to the authoritative state when they diverge, and don't assume updates arrive cleanly. And capture desync issues and related errors from the field, since desync depends on network conditions and timing you can't fully reproduce locally, so seeing when and where clients diverge under real conditions helps you find and fix the causes. Desync comes from client divergence under unreliable networks, so authoritative state plus robust network handling, verified with field data, are the core preventions.

What causes desync in multiplayer games?

Clients ending up with different versions of the game state, which happens when they diverge without a single authoritative source of truth, compounded by the network's unreliability. If clients each compute important state independently, small differences, in timing, in floating-point results, in the order events are processed, accumulate until they have meaningfully different game states, that's desync. The unreliable network makes it worse: messages arriving late, out of order, or lost mean clients receive updates at different times or miss them, causing them to drift apart even if they'd otherwise stay aligned. Without a mechanism to reconcile clients back to a correct state, these divergences persist and grow, producing the confusing bugs where players see different things. This is why preventing desync centers on a single source of truth, making the server or host authoritative so there's one correct state that clients align to rather than multiple independent ones, and on handling the network robustly so late and missing messages don't cause drift, with clients reconciling to the authoritative state when they do diverge. Desync is hard precisely because it arises from the interaction of distributed state and unreliable networks, so it requires deliberate architectural defenses rather than emerging on its own.

Should I use an authoritative server to prevent desync?

An authoritative server (or host) is the most reliable way to prevent desync, because it establishes a single source of truth that clients reconcile to, rather than letting clients diverge on independently-computed state. With an authoritative model, the server holds the canonical game state, clients send their inputs to it, and the server's view is the truth that clients align to, so even when clients temporarily drift (due to latency or missed messages), they reconcile back to the authoritative state rather than persisting in divergence. This directly addresses desync's root cause, clients having different versions of the state, by ensuring there's one correct version everyone converges on. The alternative, fully peer-to-peer or lockstep deterministic models, can work but are harder to keep in sync (lockstep requires strict determinism and is sensitive to any divergence, including subtle floating-point differences) and offer less protection against a misbehaving client. For most games, especially from indie teams, an authoritative server or host is the more robust and forgiving choice for preventing desync, and it has the added benefit of preventing cheating and one client crashing others, since the authority validates and controls the shared state. You still need to handle the network's unreliability and reconcile clients well, but authoritative state gives you the single source of truth that makes desync prevention tractable.

How to Prevent Desync in Multiplayer

Quick answer: Make the server or host authoritative so there's one source of truth, handle the network's unreliability so late or lost messages don't cause divergence, and capture desync issues from the field. Desync comes from clients diverging without a single source of truth.

Desync, clients having different versions of the game state, is one of the hardest multiplayer problems, producing confusing bugs where players see different things. Preventing it takes a clear source of truth and robust network handling. Here's how to prevent desync in multiplayer.

Make the Server or Host Authoritative

Desync happens when clients compute state independently and drift apart, so the core prevention is a single source of truth, make the server or host authoritative over important state, with clients reconciling to it rather than diverging on their own. Authoritative state prevents the divergence that is desync at its root.

Bugnet captures crashes and errors from clients and server, so desync-related issues surface. Making the server or host authoritative prevents desync by ensuring there's one correct version of the state that clients align to, rather than multiple independent versions that drift apart.

Handle the Network's Unreliability

Even with authoritative state, the network's unreliability, late, lost, out-of-order messages, can cause clients to diverge from the truth. So handle the network robustly: account for late and missing updates, reconcile clients back to the authoritative state when they drift, and don't assume updates arrive cleanly, since network unreliability is a major desync driver.

Bugnet captures errors with breadcrumbs, so network-related desync issues are identifiable. Handling the network's unreliability prevents the desync that comes from messages not arriving as expected, by keeping clients reconciled to the truth despite imperfect delivery.

Capture Desync Issues From the Field

Desync depends on network conditions and timing you can't fully reproduce, so capture desync issues and related errors from the field. Seeing when and where clients diverge under real conditions helps you find the causes and prevent the recurring desync that local testing wouldn't reveal.

Bugnet captures crashes and errors from clients and server with context, so real-condition desync surfaces. So prevent desync in multiplayer by making the server or host authoritative, handling the network's unreliability, and capturing desync issues from the field, addressing the client divergence under unreliable networks that causes desync.

Make the server or host authoritative so there's one source of truth, handle the network's unreliability so late or lost messages don't cause divergence, and capture desync issues from the field. Desync comes from clients diverging under unreliable networks.