A Valheim seed is a short text string that decides the whole map: where every biome sits, where the bosses are, where the traders stand and how much land surrounds the spawn. The dedicated server has no seed argument, so a seed only reaches a server one way - you create the world on your own PC with that seed, enter it once, and upload the two world files. Picking the seed is the part people rush. Five minutes with a map viewer and a short checklist decides whether your group spends its first week building or rowing.
What a seed is, and what it decides#
When you create a world, the game fills in a random seed of ten characters - letters and digits - and you can overwrite it with anything up to ten characters long. The string is turned into a number and that number drives the terrain generator. Two worlds with the same seed, made on the same game version, have the same land, the same biomes and the same boss and trader locations.
Seeds are case-sensitive. Midgard123 and midgard123 are different worlds, which is the usual reason a seed copied from a forum produces a map that looks nothing like the screenshots. Copy it exactly.
What the seed fixes:
- Land and water: the shape of every continent and island, every river and the ocean between them.
- Biome layout: which biome covers which area. Biomes are laid out roughly in rings by distance from the centre of the map, so Meadows dominate near the spawn and the harder biomes are further out, with Ashlands at the southern edge and the Deep North at the northern edge.
- Locations: boss altars, the Vegvisir runestones that point to them, the traders (Haldor in the Black Forest, Hildir in the Meadows, the Bog Witch in the Swamp), crypts, villages and dungeons.
- Starting point: every world starts at the sacrificial stones near the centre. The seed decides what surrounds them.
What the seed does not fix: world modifiers (combat difficulty, resource rate, portal rules), which are separate settings, and anything players do. Two servers on the same seed diverge from the first tree felled.
Seeds and game versions
A seed is only reproducible within the same world generation rules. The large biome updates changed generation for biomes that had been placeholders - Mistlands, then Ashlands - so a seed recommended before one of those updates now has different terrain in those regions. Older worlds keep the terrain that was already generated in zones somebody visited; unexplored zones generate with the rules of the version that first loads them. When you read a seed recommendation, check its date against the last big update. A list from years ago is still reliable for the Meadows and Black Forest around spawn, which have barely changed, and much less reliable for anything far out.
Why there is no seed setting on the server#
Every option a Valheim server has is a launch argument - -name, -world, -password, -port and the rest, all listed in the launch arguments reference. None of them takes a seed. When the server starts with -world "Midgard", it looks for Midgard.fwl and Midgard.db in its worlds_local folder. If they exist it loads them. If they do not, it creates a world of that name with a random seed and tells you nothing about it beyond the log line.
The seed lives in the .fwl file, a few hundred bytes of metadata. The .db holds what has changed in the world - every building, every dug hole, every dropped item. The terrain itself is not stored: it is regenerated from the seed whenever a zone is loaded. That is why the two files must always travel together. Upload a .db without its own .fwl and the server generates fresh terrain from whatever seed it has, then lays the stored buildings over it, which is how people end up with a longhouse half inside a mountain.
It also means you cannot change the seed of a world that exists. The map is derived from it, so a new seed is a new world. If that is what you want, starting a new world without losing your characters covers the switch.
Finding a seed#
There are three routes, and most groups use them in this order.
Map viewer sites
Community map viewers run Valheim's generation code in the browser: type a seed and you get the whole map, with biomes coloured and markers for bosses, traders and many dungeon types. The best-known is valheim-map.world. They are unofficial and they lag behind patches - after a generation change it can take a while before a viewer matches the game - so treat the map as a strong guide rather than a promise, and check the viewer says which game version it models.
A map viewer is a spoiler machine. It shows every boss and every trader before anyone has left the spawn. Some groups want exactly that so they can plan portals and base sites; others would rather discover the world. Settle it before somebody posts the full map in your group chat.
Seed lists and recommendations
Forum threads and subreddit posts collect "good seeds", usually ones with a large, safe starting island, every trader within reach, or a striking landmark. They save time, but remember the two traps from above: copy the seed with exact capitals, and check whether it was posted before the last generation change.
Rolling your own
Create a world with a random seed, walk around, and if you dislike the start, delete it and roll again. This is slower but needs no external site and spoils nothing beyond the starting area. The checks in the next section tell you what to look for.
What to check around the start#
A good seed for a group server is mostly about the first two or three hours: can people find what the early game needs without a boat, and is there room for everyone to build? These are the checks that matter, roughly in the order they bite.
| Check | Why it matters | What good looks like |
|---|---|---|
| Black Forest near spawn | Copper, tin, Greydwarf eyes, the Elder | A Black Forest edge within a few hundred metres |
| Eikthyr's altar | First boss, unlocks the antler pickaxe | On the starting landmass, ideally walkable |
| A Swamp reachable | Iron, the next big step | Reachable by a short sail or on foot |
| A Mountain on the same land | Silver, Moder, the frost resistance problem | Nearby mountains save a long sea trip |
| Meadows size | Room for several bases and farms | Large, flat Meadows rather than a thin strip |
| Coastline | Boats, fish, later sailing | A sheltered bay near spawn for the first karve |
| Haldor's location | Belt, fishing rod, yule hat | Within a reasonable trip of spawn |
A few of these deserve a sentence more.
The starting landmass. The spawn is always in Meadows, but sometimes the Meadows are a small island with nothing else on it, and the first copper means building a raft before anyone has the materials for anything better. Some groups enjoy that. Most groups with new players do not.
Haldor. The Black Forest trader sells the Megingjord belt, which raises carry weight, and the fishing rod. On some seeds he is a short walk from spawn; on others he is on a different continent. A map viewer marks him. Hildir, the second trader, is in the Meadows and her quests reach later biomes, so her position matters less early.
Room to build. On a shared server, the area around spawn fills up first, and everyone ends up living in the same few zones. That costs performance as well as tempers - base placement on shared servers explains why bases close together share the cost of whoever owns the zone. A seed with broad Meadows and several good harbours gives each player their own spot without a long walk.
What you do not need to check. Late-game biomes are far out on every seed. Do not reject a seed because the Mistlands look far away - they are far away everywhere, and by then your group will have portals and a longship.
Scouting a seed in single player
If you would rather not use a map viewer, you can preview a seed yourself. Create the world locally, enter it with a throwaway character, and use the developer console. In single player, the console is opened with F5 once the game has been started with -console in its Steam launch options:
devcommandsexploremapexploremap reveals the whole map for that character in that world. When you have seen enough, hide it again so your real characters do not inherit a spoiled map:
resetmapdevcommandsMap exploration is stored on the character, per world, so using a throwaway character keeps your main character's map clean whatever you do. The devcommands guide covers what else the console can do; for scouting, exploremap is the only command you need.
Making the world locally with a seed#
Once you have chosen a seed, the world has to be created on a PC that runs the game. This is the only part of the process that needs the client.
- Start Valheim, pick any character and click Start.
- Choose New World. Type the world name you want the server to use - short, no spaces, and you will need to type it exactly again later.
- Clear the random seed and type yours, with the exact capitals.
- If the dialog offers cloud saving, leave it off so the files are written to
worlds_local. A cloud world has to be moved to local with Manage Saves before it can be uploaded. - Leave world modifiers at default unless you know you want them; you will set them on the server anyway (see below).
- Enter the world, wait until the terrain has loaded, then quit to the main menu. Quitting is what writes both files.
The files are now in the local worlds folder:
Windows: %USERPROFILE%\AppData\LocalLow\IronGate\Valheim\worlds_local\Linux: ~/.config/unity3d/IronGate/Valheim/worlds_local/You will find Midgard.fwl and Midgard.db, possibly with .old copies beside them. You only need the two without a suffix.
Uploading the seeded world to the server#
The upload itself is the same as moving any single-player world, and uploading a local Valheim world walks through every way it can fail. The short version for a fresh, seeded world:
- Stop the server and wait for it to exit.
- Upload
Midgard.fwlandMidgard.dbinto the server'sworlds_localfolder. - Set
-world(or the World field on the Startup tab) toMidgard- no extension, same capitals. - Start the server and read the log.
Load world: Midgard (Midgard)If the log shows the server generating a new world instead, the name did not match a file. The server will have created a new pair under the name it was given, with a random seed. Stop it, delete that new pair, fix the name and start again. On a fresh world nothing is lost; the danger is only in doing this on a world people have already played.
On a RE:NODE server, the file manager takes both files by drag-in and the world name is a field on the Startup tab, so the whole swap is a stop, two uploads, one field and a start. Take a backup from the panel first if a world already exists on the server, so the old one can be brought back with a button.
World modifiers on an uploaded world
If you set modifiers in the local world creation dialog, they are stored in the world, but a dedicated server is configured by its launch arguments, and that is where you should set them: -preset, -modifier and -setkey on the server, so there is one place to look when somebody asks why portals take ore. World modifiers and presets lists every value. After the first start, join and open the world's settings to confirm the server applied what you intended.
Seeds on an existing server#
You may inherit a server whose seed nobody wrote down. The seed is in the .fwl, so download the pair, put them in your local worlds_local, and select the world in the game's world list - the seed is displayed there. Do not play it locally unless you mean to; a single-player session writes to the copy on your PC, not the server, but it is easy to confuse the two later.
Writing the seed down is worth the ten seconds. If the world is ever lost and the only backup is days old, knowing the seed means you can at least see the terrain again and plan where the rebuilt bases go. It does not bring the buildings back - those were in the .db - which is why real backups matter more than any seed.
Troubleshooting#
The map does not match the map viewer. Check the capitals, then the date. A viewer that models an older generation version will be wrong in regions a later update changed. The area around spawn usually still matches.
The server ignored the uploaded world and made a new one. The -world value and the file name differ, often by a capital letter or a trailing space. The log line with the world name tells you what the server actually looked for.
The terrain looks right but buildings are buried or floating. The .db and .fwl came from different worlds. Upload them as a matched pair from the same folder at the same time.
The starting area is right but a distant biome differs from the screenshots. That region was generated by a different game version from the one in the screenshots. Nothing is wrong with your files.
Players see a blank map on the new world. Expected. Exploration is stored on each character per world, so a new world starts unexplored for everyone, including the person who scouted it with a different character.
FAQ#
Can I change the seed of my server's world?
No. The terrain is generated from the seed every time a zone loads, so changing it would move every hill under every building. A different seed means a new world, made locally and uploaded.
Can the server generate a world from a seed on its own?
Not in vanilla. The dedicated server has no seed argument; without world files it generates a random seed. Create the world in single player and upload the pair.
Is the same seed the same world on Xbox and PC?
The seed drives the same generator on every platform, so on the same game version the map is the same. Crossplay players join the server's world anyway, so they see whatever the uploaded files contain.
Do I lose anything by scouting a seed with exploremap?
Not if you use a throwaway character. The revealed map belongs to that character in that world only, and resetmap hides it again. Your real characters arrive on the server with nothing revealed.
What makes a seed good for a big group rather than a solo player?
Space. A group wants large Meadows, several sheltered harbours and early biomes on the same landmass, so that ten people can each build without stacking into the same few zones around the spawn.
