Unified Xaero Worldmap

Unified Xaero Worldmap is a mod that syncs Xaero's World Map between players on a multiplayer server. Everything one player explores shows up on every other player's map, live, in every dimension and cave layer, so the server gets one shared map. It runs on Fabric, Forge and NeoForge, Minecraft 1.16.5 to 26.3.

Last updated: October 2026

Real game, two clients, default settings, played at 2x speed: the player on the left explores, and the map of another player on the right fills in a few seconds later (about 7 seconds in real time).

Xaero's World Map keeps each player's explored map to themselves. With Unified Xaero Worldmap, whatever any player explores is added to a shared map that every player sees, so a group stops mapping the same spawn area over and over.

A newly explored area reaches another player's map about 7 seconds after it was mapped. That was measured in the real game with two clients. The live save interval is 5 seconds by default, and no command or menu is involved.

Real game, two clients, default settings, played at real speed: the player on the right joins with an empty map, and the shared map fills in on its own.

A player who joins with an empty map gets the shared map filled in automatically. In a test, an 840-block route was on a new player's map 6 to 10 seconds after joining. A server map of 1000 regions took about 7 minutes at the default download rate.

Nether, End and modded dimensions sync, and so do cave layers. A dimension you are not in still receives discoveries and holds them until you arrive. A map you had before installing the mod is shared in the background, and there is no web map, file copying or command to set up.

The mod comes as 38 builds: Fabric and Forge for 14 Minecraft version families, and NeoForge for 10 of them (1.20.4 and newer). The server and every player use the same file.

Merging only adds or updates 16x16-block tiles, so nobody can wipe the shared map, and old data only fills gaps. Each player has upload and work limits, the whole map has a 4 GiB size cap by default, and sync switches itself off with one chat line if a World Map update changes something the mod needs.

Install Xaero's World Map and the mod on the server (plus Fabric API on Fabric, or xaerolib on Forge and NeoForge), give players the same mods, and syncing starts when they join. Xaero's World Map 1.46.0 or newer is required on the server and on every client.

What is Unified Xaero Worldmap?

Unified Xaero Worldmap is an unofficial add-on for Xaero's World Map that turns the explored map into one map shared by the whole server. You install it on the server and on each player's game, and nothing else needs to be set up.

Xaero's World Map normally keeps each player's explored map private. You only see the chunks you walked through yourself, so on a server with friends everyone maps the same spawn area and nobody knows what the others found. This mod changes that:

• You explore, everyone sees it. A new area appears on your friends' maps within seconds, with no reload, no menu and no command.
• Log off for a week, log back in. Your map is already filled in with everything the group discovered while you were away.
• Caves and dimensions included. Cave layers sync like the surface does, and so do the Nether, the End and any other dimension the server has. Discoveries in a dimension you are not in right now still arrive and wait for you there.
• Your existing map counts too. A map you already had before the mod was installed is shared with the server in the background, so the group map starts with everything everyone explored earlier.
• Nothing to set up. There is no web map, no file copying and no command. Install the mod on the server and on each player's game.

How does the shared map work?

Players explore as usual, and the mod passes the explored map tiles through the server to everyone else. Newly explored areas travel live. Maps that players already had travel in the background on a timer.

• Live updates. While at least one other synced player is online, Xaero's World Map is asked to save map regions every 5 seconds instead of every 60. The new tiles go to the server, which merges them into the shared map and sends them on to the other online players.
• Catch-up on join. When a player joins, the server sends the shared map in passes. By default that is 2 map regions per second, roughly 200 to 600 KB/s, until the player's map is complete.
• Existing maps. Map data a player had before joining is uploaded in the background. Every client also compares its map with the server every 120 seconds by default. That check is how a joining player's existing map reaches players who are already online.
• Merging. The shared map is merged one 16x16-block tile at a time. Tiles are added or updated and never deleted.
• What is shared. Only the explored map. Waypoints are never shared and stay private to each player.
• Where it is stored. The shared map and its config live in the world save under <world>/unified_xaero_worldmap/, so they are backed up together with your world.

Which Minecraft versions and mod loaders are supported?

Unified Xaero Worldmap supports Fabric, Forge and NeoForge on Minecraft 1.16.5 to 26.3. Fabric and Forge are available for 14 Minecraft version families, NeoForge for 10 of them (1.20.4 and newer), which makes 38 builds in total. It covers every Minecraft version that Xaero's World Map 1.46 supports.

Pick the file that matches your Minecraft version and your mod loader. The server and every player need the same file, with the same Minecraft version and the same loader. The Java column shows the Java version for that Minecraft version.

File names look like unified-xaero-worldmap-<version>+1.21.1-neoforge.jar: the mod version, then the Minecraft version, then the loader.

These Minecraft versions in between are not supported, because Xaero's World Map 1.46 does not exist for them: 1.17, 1.19.3 and 1.19.4, 1.20.2, 1.20.5 and 1.20.6, 1.21.2 and 1.21.3, 1.21.6 and 1.21.7, and 1.21.9.

What do I need to install?

On the server and on every player's game you need Xaero's World Map 1.46.0 or newer, this mod, and one support library: Fabric API on Fabric, xaerolib on Forge and NeoForge. Xaero's Minimap is optional.

Xaero's Minimap works alongside the mod and is needed on the client only. If you use it, pick a Minimap version that works with World Map 1.46: 26.4.0 or newer, tested with 26.5.x.

How do I install it on a server?

Install your loader, put Xaero's World Map, this mod and the support library into the server's mods folder, and start the server. Players put the same mods into their own game.

On the server:

1. Install your loader (Fabric, Forge or NeoForge) for your Minecraft version.
2. Put these into the server's mods folder: Xaero's World Map, this mod, and Fabric API (on Fabric) or xaerolib (on Forge and NeoForge).
3. Start the server. The shared map and its config are created automatically in <world>/unified_xaero_worldmap/.

On every player's game: the same mods as on the server, in the game's mods folder. Xaero's Minimap is optional.

That is all. When a player joins, the mod checks that both sides match, syncing starts on its own, and nothing else needs doing.

Who can join a server that uses it?

Everyone can join. The mod is optional on both sides, so it never locks a player out.

• A player without the mod joins the server normally and plays with their own, unshared Xaero map.
• A player with the mod on a server without it plays normally too. There is just nothing to sync with.
• A player on an incompatible version of this mod stays connected. Sync is off for them, and they get one chat message that says which version each side runs.
• A player on a different Minecraft version, joining through a version-bridging proxy such as ViaVersion: Xaero's World Map stores maps differently on some Minecraft versions. If the formats differ, sync turns off for that player with a clear chat message. Players on the server's own version keep syncing normally.

Is the shared map safe on a public server?

Yes. The shared map in Unified Xaero Worldmap only ever grows: merging adds or updates tiles and never deletes them, and the server limits what each player can send.

• Nobody can wipe the shared map. Merging is additive and works on one 16x16-block tile at a time. Nothing a player sends can erase or blank out what someone else explored, by accident or on purpose.
• Fresh beats stale, old never beats new. A tile you just explored updates the shared map. Old map data from before you joined only fills gaps and never overwrites something another player mapped more recently.
• Your own map files are protected. Incoming map data is merged into your map carefully, following Xaero's own save cycle. Files the mod cannot read safely, such as map files from an older Minecraft version, are left untouched and are never overwritten or deleted.
• Built for public servers. The server only accepts map data for its own dimensions and for cave layers that can exist there, and it rejects malformed data before it reaches anyone. Every player has an upload rate limit and a capped share of the server's background work. The whole shared map has a size cap on disk, 4 GiB by default. Live updates from places a player has never been near are never broadcast to others.
• It fails safe when Xaero updates. At startup the mod checks that everything it needs from Xaero's World Map is still there. If a future World Map update changes something, sync switches itself off with one chat line and one log line. Your game and your map keep working, and the mod does not crash.
• Singleplayer is untouched. Singleplayer worlds are never synced. Uninstalling the mod at any time leaves Xaero's World Map exactly as it was.

Server configuration

The server writes <world>/unified_xaero_worldmap/config.json with defaults on first start. Changes take effect after a restart. Values outside the allowed range are corrected automatically, and a broken config file is backed up and replaced with defaults instead of crashing the server. The defaults suit a survival server with 5 to 20 players.

Most servers never need to change anything. The settings people actually tune are liveSaveIntervalMillis, maxRegionsPerTick and maxStoreBytes. To switch the mod off without uninstalling it, set syncEnabled to false and restart.

Performance

Unified Xaero Worldmap adds very little to the frame time, and the heavy work runs on background threads.

• Playing alone on a server: the mod changes nothing about Xaero's own behaviour or timing.
• Own code: about 0.01 ms per client tick. All map parsing, merging and disk work runs on background threads at the lowest priority.
• Playing together: while at least one other synced player is online, Xaero is asked to save map regions every 5 seconds instead of every 60, so discoveries reach friends quickly. In an uncapped-FPS test this cost about 10% at around 2000 FPS. At normal framerates you will not notice it. Server owners can raise liveSaveIntervalMillis to trade freshness for even less work.
• How fast areas arrive: measured in the real game with two clients and default settings, a newly explored area reached another player's map about 7 seconds after it was mapped. A player who joined with an empty map had an 840-block route on their map 6 to 10 seconds after joining.
• Catching up a big map: with 1000 map regions on the server, a newly joined player was fully caught up in about 7 minutes at the default download rate. The server never fell behind ("Can't keep up") while sending it.

Known limitations

• LAN worlds: the host's own map does not sync, because Xaero already maps the host's world straight from the save. Guests who join do sync, with the host acting as the server.
• Existing maps travel on a timer, not live: map data a player already had before joining is uploaded in the background and reaches other online players at their next periodic check (every 120 seconds by default). Newly explored areas are live.
• Upgrading Minecraft: Xaero's World Map stores maps differently on some Minecraft versions (1.16.5, 1.18.2 to 1.21.4, 1.21.5 to 26.2, and 26.3 each use their own format). If your server moves to a version with a different format, the shared map starts over and rebuilds from what players upload. Nothing is deleted: the old server map is kept aside on disk. Each player's own old map syncs again once Xaero's World Map rewrites it in the new format, which happens when they revisit that area.
• Xaero's "full" cave mode is not synced. The regular cave layers are.
• Map regions you are looking at reload briefly when other players' tiles arrive for them.
• Mixed loaders on one server, such as Fabric players on a NeoForge server, have not been tested.
• Heavy artificial load, like scripted teleporting of several players into ungenerated terrain every second, can overwhelm vanilla world generation. That is a vanilla limit. The mod itself never blocks the server thread.

Frequently asked questions

How do I share my Xaero's World Map with friends on a server?

Install Unified Xaero Worldmap on the server and on each friend's game, together with Xaero's World Map 1.46.0 or newer, using the file for your Minecraft version and loader. After that, joining the server is all it takes: syncing starts on its own, with no command or menu. Everything anyone explores then appears on everyone's map, while waypoints stay private.

Does it work with Xaero's Minimap?

Yes, Unified Xaero Worldmap works alongside Xaero's Minimap, which is optional and only needed on the client. Pick a Minimap version that works with World Map 1.46, which means 26.4.0 or newer, tested with 26.5.x. The mod itself requires Xaero's World Map, not the Minimap.

Does it work on Fabric, Forge and NeoForge?

Yes, Unified Xaero Worldmap has Fabric and Forge builds for 14 Minecraft version families and NeoForge builds for 10 of them (1.20.4 and newer). The server and every player need the same file, with the same Minecraft version and the same loader. Servers that mix loaders, such as Fabric players on a NeoForge server, have not been tested.

Is this a web map like Dynmap or BlueMap?

No, Unified Xaero Worldmap is not a web map. Web map mods such as Dynmap or BlueMap show a server map in a browser. This mod fills the in-game Xaero's World Map of every player instead, and it needs no web server or open port.

Does Xaero's World Map share explored areas between players by itself?

No, Xaero's World Map on its own keeps each player's explored map private to that player and has no built-in sharing of explored areas. Unified Xaero Worldmap adds that sharing on a multiplayer server, so every player's map fills in from what the whole group explored.

How fast do new areas show up for other players?

In a test in the real game with two clients and default settings, Unified Xaero Worldmap showed a newly explored area on another player's map about 7 seconds after it was mapped. The live save interval is 5 seconds by default, and a server owner can change it with liveSaveIntervalMillis. A player who joined with an empty map had an 840-block route on their map 6 to 10 seconds after joining. Maps that players already had before joining arrive on a 120-second check by default.

Does the server need Xaero's World Map?

Yes, the server as well as every player. That's what lets new areas land on your map immediately, even for dimensions you haven't visited yet.

Can other players see my base?

Yes, if you explored it: every area anyone maps becomes part of the shared map. That's the point of the mod, so keep it in mind on servers with secret bases. Waypoints are never shared; they stay private to each player.

Do waypoints sync?

No. Only the explored map itself syncs.

Can a griefer wipe or mess up the shared map?

No. Merging only ever adds or updates tiles, nothing a player sends can delete what others explored, and data for places a player has never been near is never broadcast.

Does it sync my singleplayer maps?

No. Singleplayer worlds are never touched. A world opened to LAN syncs for the guests who join, not for the host.

What happens to players who don't have the mod?

They join and play normally, with their own personal Xaero map.

What if Xaero's World Map updates?

The mod checks itself at startup. If something it needs has changed, it turns sync off with one chat message and carries on. Nothing crashes and your map keeps working.

Can I turn it off without uninstalling?

Yes: set syncEnabled to false in the server config and restart.

Where is the shared map stored?

In the world save, under <world>/unified_xaero_worldmap/. It's backed up together with your world.

Is this made by Xaero?

No. It's an independent, unofficial add-on. See Credits.

Credits

This project is an unofficial add-on for Xaero's World Map by Xaero96 (CurseForge Project ID: 317780).

It extends Xaero's World Map with server-wide shared map synchronization, allowing explored map tiles to be shared between players while continuing to use Xaero's World Map as the underlying map system.

Xaero's World Map is a required dependency, and this add-on does not function without it. Xaero's Minimap is optionally supported but not required.

All credit for the original map system, map rendering, map storage, exploration tracking and related functionality belongs to Xaero96 and the original Xaero's World Map project.

This project is independent, unofficial, and not affiliated with or endorsed by Xaero96. It does not include or redistribute Xaero's World Map or Xaero's Minimap.

• Author of this add-on: Obscura (CurseForge user Navrelis)
• Licence: CC0-1.0
• Original project: https://www.curseforge.com/minecraft/mc-mods/xaeros-world-map
• Original author: Xaero96
• CurseForge Project ID: 317780