BlueMap Marker Tool

A NeoForge server-side mod that adds a click-to-draw marker editor directly inside the BlueMap web interface.

Draw area polygons and text labels on the live map. Markers are saved to the server and visible to every viewer — no client mod required.

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Requirements

• Minecraft 1.21.1
• NeoForge 21.1.x
• BlueMap NeoForge mod installed on the same server
• An open port for the marker API (separate from BlueMap's web port)

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Installation

1. Drop BlueMapMarkerTool-1.0.jar into your server's mods/ folder alongside BlueMap.
2. Start the server. The mod auto-generates its config and deploys the editor script into BlueMap's webroot — no manual file copying needed.
3. Open config/bluemap-marker-tool.toml and set api_port to a port that is open and reachable on your server (see below).
4. Restart the server.
5. Open the BlueMap web interface in your browser.

Port note: The marker editor saves changes to the server via a small REST API that runs on its own port, separate from BlueMap's web port. BlueMap's built-in web server is static-only and cannot receive saves, so this mod opens a second listener to catch marker edits. You must allocate an open port on your host — it must NOT be the same port BlueMap's web server uses, or neither will start. On managed hosts (e.g. PebbleHost) this is done via the "Additional Ports" panel. The default is 8034. Change it to whatever port your host has assigned you if 8034 is unavailable.

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Controls

Action	How
Open / close editor	Hold Space, then press Tab
New area marker	Click ▰ New Area in the panel, then click the map to place corners
New text label	Click T New Text in the panel, then click the map to place it
Finish drawing	Click ✓ Done
Edit / move vertices	Select a marker, click ✎ Edit, then drag vertices on the map
Insert a vertex	In Edit mode, click on the outline between two existing vertices
Delete a vertex	In Edit mode, double-click a vertex
Delete a marker	Click ✕ next to it in the marker list
Set text zoom threshold	Use Min dist / Max dist fields (camera distance in blocks at which the label appears/disappears)
Copy BlueMap HOCON config	Click 📋 Copy BlueMap config to copy a static marker-sets block for overworld.conf

Markers are saved to the server automatically after every edit and are immediately visible to all viewers.

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Config (config/bluemap-marker-tool.toml)

# Port for the marker REST API. Must be open/reachable on your server,
# and MUST be different from BlueMap's web-server port.
api_port = 8034

# BlueMap map ID to push area markers to (matches the folder name under bluemap/maps/).
map_id = "overworld"

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How it works

On startup the mod:

• Extracts area-draw.js from the jar into BlueMap's webroot
• Registers it with BlueMap's webapp API so it loads automatically in every browser
• Writes xyn-config.json to the webroot so the editor knows which port to talk to
• Starts a lightweight HTTP server on api_port

Marker data is stored in config/xynovia/markers.json and pushed to BlueMap's live marker API on every save so viewers see updates without a page refresh.

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Credits

Built on top of BlueMap by BlueColored.