ValheimWebMap

Valheim Web Map

A server-side BepInEx plugin for Valheim 1.0 that serves a live, interactive web map of your world. Players install nothing.

• Default world only. The map is rendered from the game's world generator: biomes, terrain,

rivers, forests and water, exactly as a fresh world looks. Buildings and terraforming are not shown.

• Fog of war. Only ground that players have actually walked is visible. Exploration is tracked

on the server and saved between restarts; unexplored terrain never leaves the server.

• Live players. Players who turned on Visible to other players on their in-game map are drawn

with their name, facing direction and biome, and updated every second. Everyone else is listed as online with their position hidden.

• Familiar controls. Scroll or pinch to zoom, drag to pan, double-click to zoom in, click a

player to follow them. Works on phones. The URL keeps the view (#x,z,zoom) so it can be shared.

• Cartography tables. Markers that players share on an in-world cartography table appear on

the web map, grouped by the player who placed them so each player's markers can be switched on and off. The explored area shared on the table lifts the fog as well. Deaths of players who were sharing their position are marked where they happened. Markers close together on screen are grouped into a numbered bubble until you zoom in far enough to tell them apart.

• Play history. Every connection is recorded as a session with its length and the deaths

that happened in it, so the History tab shows how often, how long and how deadly each player's time on the server has been. Quick reconnects are shown as one session and very short ones are left out of the list. Nothing is needed from the clients.

• Existing worlds work. Zones in the save file are only generated near players, so on first start

the plugin reveals everything anyone had already visited before the mod was installed.

• No authentication. Meant to sit behind your own reverse proxy. The web server only starts

when the process is the game server, so the plugin is inert if it ends up on a client.

Built and tested against Valheim 1.0.16 (dedicated server, Linux) with BepInExPack Valheim 5.4.2351.

Screenshots

Fog of war over a world where a few areas have been visited, with two players sharing their position and one who is not:

Zoomed in: terrain, rivers, forests and mountains come from the world generator at 5 m per pixel. Players show their facing direction, biome, time online and deaths:

The History tab, with one player's recent sessions expanded:

On a phone the player panel folds away behind a button:

Install

With a mod manager (r2modman, Gale or the Thunderstore app), pick the Valheim Dedicated Server profile and install ValheimWebMap; BepInExPack Valheim comes along as a dependency. Then skip to step 3.

By hand:

1. Install BepInExPack Valheim

on the server.

1. Download the release zip and copy plugins/ValheimWebMap/ValheimWebMap.dll to

<server>/BepInEx/plugins/ValheimWebMap/ValheimWebMap.dll.

1. Start the server once. The config is written to BepInEx/config/com.valheimwebmap.cfg.
2. Open http://<server-ip>:3000/.

Startup log lines to expect:

[Info   :Valheim Web Map] Web map listening on http://*:3000/
[Info   :Valheim Web Map] Revealed 412 previously visited zones (3.1% of the world explored)
[Info   :Valheim Web Map] Tracking world 'Midgard'
[Info   :Valheim Web Map] Rendered preview world map (1024 px) in 0.4s; rendering 4096 px map with 4 thread(s)
[Info   :Valheim Web Map] Rendered world map (4096 px) in 25.3s

The map is usable right away at preview quality; the full-resolution render takes from a few seconds to a couple of minutes depending on the CPU and is then cached on disk, so later starts are instant. Map data lives in BepInEx/config/ValheimWebMap/<world name>/:

| File | Purpose | | --- | --- | | basemap_<resolution>.bin | Cached world render. Redone automatically after a game update. | | explored.bin | Fog-of-war state. Delete it to start over with a black map. | | history.json | Play sessions, deaths (with position when shared) and character ids per player (keyed by Steam or PlayFab id). Human readable. |

Docker (lloesche/valheim-server)

With BEPINEX=true, BepInEx lives at /opt/valheim/bepinex/BepInEx on the data volume. Put the plugin in /opt/valheim/bepinex/BepInEx/plugins/ValheimWebMap/ and publish the port (-p 3000:3000/tcp). The config and map data end up under /config/bepinex/.

Reverse proxy

The page uses relative URLs, so it can be served from a sub-path as long as the path ends in a slash (https://example.com/valheim/ → http://server:3000/). Example for nginx:

location /valheim/ {
    proxy_pass http://127.0.0.1:3000/;
    proxy_set_header Host $host;
}

Add whatever authentication you want at the proxy; the plugin has none.

Configuration

BepInEx/config/com.valheimwebmap.cfg, read at startup.