How do I set up a BlueMap live 3D map for my Minecraft server?

BlueMap is a live 3D web map of your Minecraft world that players open in a browser. It works on Paper and Spigot as a plugin, and on Forge and Fabric as a mod.

Install it: on Paper or Spigot, open the Plugin Manager page, search for BlueMap, and install it. The panel places the JAR in plugins/ for you. On Forge or Fabric, use the Mod Manager page instead. Start the server once so BlueMap generates its config files, then stop it.

Let BlueMap download its resources: in File Manager, open plugins/BlueMap/core.conf and set accept-download: true. BlueMap needs this to fetch the block and texture resources it renders with. Save the file.

Give the map a port: BlueMap serves the map from its own webserver. Add a second port to your server on the Network page (New Allocation), then open plugins/BlueMap/webserver.conf and set port to THAT new allocation port and ip: "0.0.0.0" so it is reachable. Do not leave it on the default 8100: a server can only be reached on the ports allocated to it. Save. If the New Allocation button is unavailable, your plan needs its allocation limit raised; contact support and we will enable it.

Apply the new port with a full restart: Stop the server, then Start it (a plain Restart may not be enough). A server only exposes the ports it was allocated at the moment its container starts, so a port you just added goes live only after a fresh Start. BlueMap then renders your world in the background; the first render of a large world is CPU and disk heavy and can take a while. Open the map in a browser at your server IP and the allocation port you set, for example http://123.45.67.89:25581 (use your own IP and port, not 8100).

Resource note: rendering a big world uses a lot of CPU and memory, so give the server headroom. On a small plan a full first render can slow the game while it works. You can limit which worlds appear under plugins/BlueMap/maps/ if you only want certain worlds on the map.