Is P2P Safe for Multiplayer? P2P vs Relay vs Dedicated Server, Honestly (2026)

Every few weeks someone posts "is P2P safe?" and gets fifty replies that contradict each other, because the question is underspecified. P2P is not one thing you can bless or condemn - it is a networking topology with a specific set of tradeoffs, and whether those tradeoffs are acceptable depends entirely on your game. A cozy 4-player co-op farming game and a ranked competitive shooter get opposite answers, and both are correct.

So instead of a verdict, here is the honest decomposition: what P2P actually exposes you to, what a relay fixes and what it does not, and when you have to bite the bullet on a dedicated authoritative server. Then a genre-by-genre call so you can find your own case.

What "safe" actually means (three separate questions)

"Safe" bundles three concerns that people argue past each other about. Separate them and the P2P question gets answerable:

• Privacy. In raw P2P, peers connect directly, which means every player learns every other player's IP address. That is a doxxing risk and, more commonly, a griefing vector: a salty opponent DDoSes the player who is beating them and drops them from the match. This is not theoretical - it is a routine complaint in competitive P2P games.
• Integrity (cheating). In P2P, one machine is usually the host and runs the authoritative simulation. That host is a player's PC. A cheating host owns the truth of the match - it can hand itself resources, rewind, or lie about outcomes - and no client-side anti-cheat can stop the machine that is the referee. This is the failure mode most people underrate.
• Stability. If the host is a player and the host quits, crashes, or rage-disconnects, the match either dies or has to perform host migration - freezing everyone while a new host takes over and hoping the state transfers cleanly. Host migration is doable and often janky, and it is a permanent tax you pay for not having a stable server.

Raw P2P is weak on all three. Every architecture above it is a way of buying back one or more of these, and the cost rises with how many you buy.

The middle rung: a relay fixes privacy, not authority

The most common upgrade from raw P2P is a relay, and it is where a lot of the "is EOS too good to be true?" confusion comes from. A relay routes peer traffic through a middleman server - Steam Datagram Relay, the relay inside Epic Online Services, or a custom UDP relay - so peers never see each other's IPs and NAT traversal mostly stops being your problem. Relays are genuinely great value, often free, and they solve the privacy question cleanly. This is why services that offer relay-based networking feel like a free lunch.

The part the free-lunch framing hides: a relay is a transport, not an authority. It moves packets privately and reliably; it does not decide what is true. If your host was authoritative before the relay, it is still authoritative after. The cheating-host and host-migration problems are exactly where you left them. So "we added EOS relay, are we safe now?" is answered: safer on privacy, unchanged on integrity and stability. That is often the right trade for a co-op or casual game and the wrong one for anything competitive.

The top rung: dedicated authoritative servers

When integrity actually matters - ranked play, a shared economy, a leaderboard worth cheating for - you move authority off the players entirely, onto a dedicated authoritative server. Now no player owns the truth, so a cheating client can lie all it wants and the server rejects the impossible; no player quitting can end the match; and IPs are never shared because everyone talks to the server, not to each other. You solve all three questions at once.

The cost is real and worth stating plainly: you are now running servers, which is money and operational work - orchestration, scaling with player count, and the netcode discipline of client-side prediction so authority does not feel laggy (the same reconciliation work covered in rollback netcode). This is the tradeoff people are dodging when they "just use P2P", and dodging it is fine right up until your game has something worth cheating for.

The decision, by genre

• Co-op PvE, cozy, sandbox with friends (Valheim-like, farming, small survival): P2P or listen-server with a relay is usually fine. Cheating mostly hurts the cheater's own friends, IP leaks are the main real risk, and a relay handles that. Add an authoritative host option for players who want a persistent world that survives the host logging off.
• Competitive PvP, ranked, anything with an economy or leaderboard: dedicated authoritative server, not negotiable. The host-can-cheat problem is fatal to competitive integrity, and no relay or client anti-cheat fixes it. If you cannot afford dedicated servers, you cannot afford competitive integrity - scope the game accordingly.
• Party games, social spaces, async: relay-backed P2P is usually the sweet spot - low stakes, cost-sensitive, and privacy is the only real threat. Reach for authority only if a specific feature (persistent scores, trading) needs it.
• Large concurrency, persistent world, MMO-lite: authoritative servers from day one; P2P does not have a coherent story for hundreds of players sharing state.

The meta-point: pick topology from your threat model, not from wiring difficulty. Raw P2P is easiest to stand up and hardest to fix later, because ripping authority out of the client after launch is a rewrite. If there is any chance your game becomes competitive, plan for authority early even if you ship P2P first.

FAQ

Is P2P safe if I use Epic Online Services or Steam relay?
Safer, specifically on privacy - the relay hides player IPs and handles NAT, which removes the DDoS/doxxing vector. It does not make the host non-authoritative, so it does not stop a cheating host or fix a host quitting mid-match. Good enough for co-op and casual; not enough for competitive.

Can a cheating host be stopped in P2P?
Not really. The host runs the authoritative simulation, so it defines truth, and client-side anti-cheat cannot police the referee. The only real fix is to move authority off the players onto a dedicated or hosted authoritative server. If cheating would hurt your game, that migration is the whole point.

Does P2P leak my players' IP addresses?
Raw P2P does - peers connect directly, so they see each other's IPs. A relay hides them by routing through a middleman. If you ship raw P2P with no relay, assume competitive players will eventually weaponize the IP exposure against each other.

Where Crux fits

Crux is a managed game backend for teams that need authority without standing up and operating their own server fleet. When your game outgrows raw P2P - because it added a leaderboard, an economy, ranked play, or a world that should outlive the host - Crux gives you the authoritative primitives (server-owned state, validated mutations, player auth, a server registry) so the truth lives off the players, with flat pricing instead of a surprise hosting bill. You can keep P2P or relay for the cheap, low-stakes paths and put authority only where your threat model demands it. See the full picture in the Crux overview, or read what an authoritative game server actually is for the foundation.

The honest one-liner: P2P is not unsafe, it is un-authoritative - and whether that is a problem is entirely a question of what your game is protecting.

Cost decides this as often as trust does. The hosting-cost ladder runs from player-hosted through relay to on-demand allocation.