Iron Gate Studio's official dedicated server documentation, published in April 2024 and still the reference operators work from, explains how to run a Valheim server. It is written for operators, not engineers. Put it next to the patch notes and FAQ from Valheim's 1.0 release on September 9, 2026, though, and the architecture behind the instructions comes into focus: two server configurations, a hard player cap, and a hosting model that leans on the community by design.

Indirectly, Valheim's approach shows what happens when a small studio makes infrastructure decisions that scale far beyond what their team could have managed alone.

The 10-Player Cap

Valheim's object synchronization system uses a structure called a ZDO (Zone Data Object). Every entity in the world (players, creatures, building pieces, tamed animals) is represented as a ZDO. When a ZDO changes state, the full object is re-sent rather than just the changed fields. Simpler to implement and more mod-friendly, but bandwidth-heavy. As player count grows, so does the volume of active ZDOs in a given area, and the total state data per tick scales with it.

Community analysis of the game's networking assembly, documented in detail on James A. Chambers' blog, found hard-coded send and receive rate limits in the ZDO manager. Mods can lift those limits, but community testing found performance degrading noticeably approaching 5-6 simultaneous players. The 10-player ceiling is the visible surface of a deeper bandwidth budget. Large player-built structures and tamed animal populations draw on that same budget independently of player count.

The cap is also the number 1.0 left alone. Iron Gate shipped on four additional platforms, upgraded the engine, and rewrote how worlds are saved, and the limit sits exactly where it always has. "Just like it is now, Valheim 1.0 will be a game for 1-10 players," reads the 1.0 FAQ. A limit that holds through a release of that size is not a placeholder waiting on tuning. It is the shape of the synchronization model itself, and moving it would mean rewriting how state replicates rather than raising a number in a config.

That is the part worth sitting with. Player caps set early in development tend to calcify, because by the time the cap starts to chafe, the architecture underneath it has years of content built on top.

A Free Binary, A Thriving Ecosystem

One of Iron Gate's most consequential infrastructure decisions wasn't technical. It was economic.

The dedicated server binary is free to anyone through Steam Tools, listed in the user's library as a tool, with no game purchase required. Iron Gate publishes the full setup guide on their official site, including Docker instructions, launch parameters, admin commands, and backup configuration. They hand operators everything they need and step back.

The effect is that server costs and operations sit with the community and with commercial hosting providers. Companies like G-Portal, BisectHosting, and Nitrado host thousands of Valheim servers, handle DDoS protection, provide control panels, and run customer support, none of which Iron Gate pays for. What might have been a cost center is instead a distributed hosting supply chain funded by players willing to pay a monthly rental rather than run their own hardware.

For studios thinking about community servers, this model is worth examining. The free binary strategy works because it creates a market that serves players without requiring the developer to operate it. Studios that want more direct involvement, including the ability to offer server rental from within the game itself with provisioning handled automatically and revenue flowing back to the studio, can explore orchestration platforms built for exactly that.

Portable Worlds

A Valheim world is a folder. Each one sits in its own directory named after the world, and a save writes only the areas that changed. The 1.0 patch notes describe a "new save system" that "splits world data across chunks to reduce how much data is serialized and written to improve performance, and is designed to be resilient against mid-write failures."

The design answers two problems at once. Rewriting an entire world on every autosave is cheap on a fresh map and punishing on one buried in player structures, and a crash mid-write can take the whole file with it. Chunked writes bound both.

What matters for operators is that the world is a folder on disk, held by whoever runs the server. A group that self-hosts can migrate to a rented server by copying it. A group renting from one provider can switch to another by downloading a backup and re-uploading it. There is no cloud lock-in, and Iron Gate's documentation treats moving worlds as routine.

For players, that means genuine ownership of their world. For developers, it is a reminder that persistence architecture shapes player trust. Worlds that can be held, moved, and backed up are worlds players invest in long-term. Locking world state to a proprietary service might simplify development, but it creates exactly the kind of dependency players notice when things go wrong.

Two Server Configurations, One Game

Most games ship one networking backend and live with its limitations. Valheim ships two.

The Steam backend connects players directly over Valve's networking layer. It is clean, low-overhead, and requires no intermediaries. It also reaches only Steam users on PC.

The crossplay backend routes traffic through Microsoft Azure PlayFab Party relay servers, and it is what puts Steam, Microsoft Store, Mac App Store, Humble, Xbox, PlayStation 5 and Nintendo Switch 2 players in the same world. Iron Gate's 1.0 FAQ is unambiguous: "Valheim will support crossplay between all platforms."

One argument picks between them. The -crossplay flag comes enabled in the example launch scripts that ship with the dedicated server, which makes reaching every platform the path of least resistance and running Steam-direct the deliberate act. For a game whose audience largely sits outside Steam, that default is the strategy in a single flag.

Azure's Relay

PlayFab Party is Microsoft's relay network for game multiplayer. A Valheim server in crossplay mode connects to one of Azure's regional relay nodes rather than accepting player connections directly. Players connect to that relay, not the server itself. The relay handles routing between them, along with public server advertising and cross-platform player identity.

The documentation is candid about what this costs. Crossplay players are more likely to experience lag, timeouts and disconnects than players on the direct Steam backend. The relay adds a network hop, and its location is chosen automatically based on proximity to one of roughly 17 Azure regions. Operators have no input on which relay their players land on. A server in one region can end up routing traffic through a relay far from part of its player group, with no recourse.

This is a trade-off common to relay-based architectures, and it is worth understanding before choosing one. For a breakdown of how relays compare to authoritative servers and peer-to-peer, read Edgegap's explainer on networking types.

One alternative is replacing a general-purpose relay with a small dedicated server instance deployed close to the player group. A sub-0.25 vCPU game server at an edge location provides server authority without the extra relay hop. Platforms like Edgegap's orchestration network make fractional deployments viable across 615+ global locations, which combines the accessibility of relay-style setups with the latency profile of a direct connection.

Crossplay or Mods: Pick One

The dual configuration comes with one consequence operators need to plan around: crossplay and mods do not run together.

The widely-used mod loader BepInEx hooks into Valheim's Steam networking layer. Enabling crossplay replaces that layer with the PlayFab stack, and BepInEx does not load. The two networking stacks share no common abstraction layer, so there is no hybrid option.

Iron Gate is direct about where mods stand. Because they offer no official mod support, they "cannot guarantee that any mods will be functional," and the console versions ship with none at all. The 1.0 engine upgrade made that concrete for operators who spent launch week rebuilding mod lists against a moving target.

The decision maps cleanly to who is in your player group. A group on Steam can run a modded server on the Steam backend. A group that includes console players needs crossplay, and with it, a vanilla server. It is a practical constraint, not a failure of design.

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[Editor's note] Unlike other entries in this series, this article draws from Iron Gate Studio's official dedicated server documentation, the Valheim 1.0 FAQ and patch notes, and the Valheim community wiki, rather than a developer conference talk or postmortem. The architectural facts are documented and verifiable. The interpretation of why those decisions were made is our own, and is not stated directly by Iron Gate.

This article is based on and cites the original documentation and patch notes by Iron Gate Studio, published on valheimgame.com, with supporting networking analysis by James A. Chambers. All rights in the original content are owned by their respective owners.