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How to host a Valheim dedicated server (and find your seed)

A dedicated server lets your Valheim world live on without you online, so friends can build while you sleep. Whether you host it on your own machine or rent one, the seed is the one string you'll want to keep handy — and you can pull it straight out of the world file.

Self-host vs rent

Self-hosting is free: run the Valheim dedicated server tool on a spare PC and your world idles there. The cost is your machine staying on, your home IP being the address, and you handling uptime and updates. Renting a hosted server flips that — someone else keeps it online 24/7, you get a stable address, and patches are their problem. Pick self-host for a casual group, rent if you want zero fuss and friends in different time zones.

Port forwarding

If you self-host, the server listens on UDP ports 2456–2458 by default. Forward those in your router to the host machine, or your friends will time out at the menu. Use a static LAN IP for the host so the forward doesn't drift after a reboot. Renting skips this entirely — the provider opens the ports for you and hands you a connect string.

Finding your seed in the .fwl file

Every world ships as two files: a .db (the live save) and a .fwl (the world metadata). The .fwl stores the world name, the seed string, and the generation parameters the game used to build the terrain. On Windows you'll find them under AppData/LocalLow/IronGate/Valheim/worlds (or worlds_local for single-player exports). The seed sits in that .fwl, and it's the exact string you'd type into a viewer. Copy it — that's your world's identity, independent of its display name.

Showing the map to friends

Once you have the seed, paste it into our free seed viewer and you can hand the link to your group: they'll see biomes, boss altars, Haldor and dungeons without owning the file. It's the fastest way to answer "where's the swamp?" in voice chat. For the theory behind seed versus world identity, read our map seed vs world seed explainer.

Server config basics

The server reads a small start script or config file where you set the world name, a public password, and whether the server appears in the community list. Match the world name exactly to the .fwl you uploaded, or the server spins up a brand-new empty world and your seed is ignored. Set a password for private groups; leave it blank only for open communities. Most rented hosts expose these as a web panel, so you rarely edit the file by hand — but the world-name-to-seed link is the one setting worth double-checking before every launch.

Backing up and sharing

Back up both the .db and .fwl together — the .db alone is useless without its metadata. Zip them before any update, and keep a copy off the machine. To move a world to a rented server, upload the pair and point the server config at the world name. For a full walkthrough on getting the string to your friends, see our seed-sharing guide, and browse the blog index for more server tips.

Measured case: pick the seed before the hardware

Server guides start at ports and RAM, but the decision that shapes every hour afterward is the seed — because on a shared world, geography is a group expense. On HHcLC5acQt, the real 1.0 generator puts the first altar 440 meters from spawn and the nearest trader 1,644, so every player's errands stay short and the group's portals all reach far biomes early. On tyeDWcN7cp the nearest trader measures 3,441 meters out — on a five-person server, that distance is paid by every single player unless someone builds a shopping spoke early. Compact seeds do not just start faster; they keep five separate schedules from drifting apart. Pick the map together in the seed viewer before anyone rents anything.

Hardware and bandwidth reality check

Valheim's dedicated server is modest by modern standards: a spare PC with a few gigabytes of free RAM handles a full group, and the engine itself is rarely the bottleneck. The bottleneck is your home internet's upload speed, because every player's world state streams through it. Four friends exploring four different corners of the map quadruple the traffic compared to everyone staying together. If your upload is thin, either keep the group compact or rent — a hosted server also survives the landlord of the household deciding to reboot the router mid-raid. Whatever you choose, run the server tool once before inviting anyone, because the first launch does housekeeping you do not want an audience for.

Version pinning: the hidden uptime killer

The quiet failure mode of long-running servers is version drift. A world generated on one major version stays on that generation even as the game updates around it, and clients on the wrong version simply cannot connect. After big patches, coordinate the upgrade: host patches first, everyone else follows, and nobody connects in between. This is also why the seed conversation from the section above matters long-term — a world born on 1.0 stays coherent precisely because the server pins the version, which is the same determinism our seed generator explainer describes. Pin the version, back up the file pair before each update, and your server survives years.

Network doors that must actually be open

Most "my friends can't connect" reports are not Valheim problems — they are port problems. A self-hosted dedicated server needs UDP 2456-2457 forwarded to the host machine, plus 2458 for the Valheim companion port; if you self-host behind a router you did not configure yourself, this is the first place to look. Hosted rental servers handle this for you, which is a real part of what the monthly fee buys beyond the hardware.

FAQ

Can I move my single-player world to a dedicated server?

Yes. Copy the .db and .fwl pair into the server's worlds folder and point the config at the exact world name. The seed travels inside the .fwl, so the world regenerates identically — buildings, explored map and all, because those live in the .db.

Do all players need the same game version?

Yes. The server and every client must run the same version or connections get refused. After a major update, expect a waiting period while the host patches — that is the price of version-pinned worlds.

How many players can a Valheim server hold?

Valheim is designed around small groups — up to ten works comfortably. On a self-hosted box your home upload bandwidth is usually the real limit, not the game engine.

Does the seed affect server performance?

Barely. The world is computed on demand from the seed, not held in memory in advance, so a seed that generates dramatic terrain costs the same to run as a flat one.

Sources & further reading