Rust custom maps, world size and seeds

A Rust server gets its map one of two ways. A procedural map is generated from server.seed and server.worldsize: the same seed, size and game build always produce the same terrain, so you can preview a map before wipe day and choose it on purpose. A custom map is a .map file made in an editor, usually RustEdit, and served to players from a public URL that you set in server.levelurl. Size is the decision that matters most either way - it sets how far apart players live, how many monuments spawn and how much memory the server needs. This guide covers choosing both, hosting a custom map so downloads do not fail, and what changes when the monthly update lands.

Procedural maps: seed, size and level#

Three launch-line convars define a procedural world:

+server.level "Procedural Map" +server.seed 1234567 +server.worldsize 3500

Barren is the procedural generator with far fewer trees and decorative objects; it is used for lighter, more open maps and arena-style play, and how much it saves depends on what players build on it. The fixed built-in maps such as Hapis Island are hand-made and ignore seed and size.

Put these on the launch line, not in server.cfg, so the command that started the server records the map. If you omit the seed, the server chooses one and uses it for that save. Change seed or size later and you get a new map on the next start; the old save does not load onto new terrain.

The server writes the generated terrain to a file named after its inputs, for example proceduralmap.3500.1234567.<version>.map in the identity folder. That file name is the quickest way to answer "what seed are we on" without opening the startup settings. Rust wipes without losing your players covers the save files that sit beside it.

Choosing a world size for your population#

Size is a population decision first and a performance decision second. Too big and players spend the wipe walking; too small and every group lives in someone else's line of sight. The area grows with the square of the edge, so 4500 is not 50% bigger than 3000 - it is about 2.25 times the land.

Size into your realistic peak, not your hopes. A new server with twenty regulars on a 4500 map feels dead; the same twenty on 3000 have a lively wipe. You can always grow the map at the next wipe.

Bigger maps cost resources in three ways: more terrain held in memory, more monuments and their NPCs, and room for more bases and therefore more entities. Generation itself is the peak - the first start after a wipe briefly needs more memory than the finished map does. Server performance and entity count has the detail, and the planned how much RAM a Rust server needs covers sizing.

Previewing and picking a seed#

Picking a seed blind means you discover on wipe night that the map has no water near the outpost, or that a large monument fell into the sea. Preview first.

1. Shortlist seeds at your chosen size using a map preview site. RustMaps is the widely used one: enter size and seed and it shows terrain, monuments and roads for the current game version.
2. Check the things your players care about: a mix of large monuments, a road and rail network that connects them, enough inland area for building, and no monument your community counts on missing.
3. Confirm on a test server after the monthly update. Generation can change between versions, and a preview made against last month's build is not guaranteed for this month's.
4. Note the seed in your wipe plan so the person running wipe day does not improvise.

Previewing sites need time to process new versions after an update, and a brand-new seed may take a few minutes to generate on their side. Have two or three candidates ready.

What makes a good procedural map

Previews make it easy to reject bad seeds, but it helps to know what you are looking for. The features that change how a wipe plays out:

• Monument spread. Large monuments such as Launch Site, the Military Tunnels and the Airfield are where high-tier loot and fights happen. Clustered on one side, they hand that side of the map to whoever builds there first. Spread out, they give every region something worth fighting over.
• Safe zones. Outpost and Bandit Camp are where players trade and recycle without being shot. A map where both are tucked into one corner forces long trips for half the server.
• Roads and rail. A connected road and railway network makes vehicles and the train useful. A map where the rail line is broken into pieces wastes one of the game's systems.
• Coastline and water. Long coastlines mean more boat play and more fishing villages; inland lakes and rivers give builders defensible spots. Islands just off the coast are favourite base spots for large groups.
• Building space. Some seeds bury most of the land in steep mountains or snow. Players want flat ground near resources in every biome.

No seed is perfect, and players will build where they build. The point of previewing is to avoid the obviously lopsided maps that make a wipe feel decided on day one.

Custom maps: what they are and where they come from#

A custom map is a complete world saved as a .map file - terrain, monuments, prefabs, spawn points - made in RustEdit, the third-party editor most map makers use. They exist for servers that want something the generator cannot make: themed islands, arena maps, hand-placed custom monuments, roleplay towns, or a deliberately balanced competitive layout.

There are three ways to get one:

• Free maps shared by their makers, usually older or simpler.
• Paid maps from marketplaces such as Lone.Design and Codefling, typically with updates after game changes. Read the licence: most allow use on your servers but not redistribution.
• Commissions from map makers, for a map nobody else has.

Some custom maps need a server-side extension to work fully. The RustEdit extension provides features map makers place in the editor - things like custom NPC spawns, IO logic and other map-defined behaviour. On Oxide it is a .dll that goes into RustDedicated_Data/Managed; Carbon handles extensions its own way. The map's documentation will say what it needs. Carbon vs Oxide has the compatibility detail.

Hosting the map file with server.levelurl#

A custom map replaces the procedural trio with one convar pointing at a URL. The server downloads the file at start, and so does every player's client the first time they join.

+server.levelurl "https://maps.example.com/rust/longship-v3.map"

The URL has to be a direct download - a request for it returns the file itself, not a web page about the file. That rules out several obvious choices or means you have to use their special forms.

Three rules prevent most wipe-night failures:

1. Change the file name every time the map changes. Clients cache maps by name. If you replace longship.map with an updated version under the same name, players with the old copy load the old terrain and fail to join or see glitches. longship-v3.map then longship-v4.map avoids it.
2. Use HTTPS on a host that will be up at wipe hour. Every player who has not downloaded the map hits the URL in the first minutes after the wipe. A personal link with a bandwidth cap will fail exactly then.
3. Test the URL from outside. Paste it into a browser on a different network. If you see a web page, a login prompt or a warning, so will the game.

Custom map files are larger than people expect, often tens of megabytes and sometimes more for detailed maps. Every new player downloads it once per version, and on wipe night that is most of your population within a few minutes. Multiply file size by your peak player count to see what the host has to serve in that burst, and choose a host that does not throttle or cap it. On the player's side, a slow download looks like the game hanging on a loading screen; tell people in your announcement that the first join takes longer, so they wait instead of assuming the server is broken.

If you already run a site, hosting the map beside it is simplest. A static file on a web plan with a domain and an automatically issued certificate is a perfectly good map host; on RE:NODE, web hosting plans include a reverse-proxy slot that issues and renews the certificate once your A record points at the address shown. Static site hosting covers serving plain files.

Custom maps and the monthly update#

Custom maps are fixed files, so procedural changes in the monthly update do not move their terrain. They are still affected in two ways.

• Prefabs change. If Facepunch modifies or removes an object the map uses, the map can fail to load or lose pieces. Map makers publish updated files after updates; paid maps usually include them.
• Extensions change. The extension a map depends on may need its own update before map features work again.

Treat a custom map like a plugin on wipe day: update the game, check for a new map version and a new extension build, upload with a new file name, change server.levelurl, start, and walk the map before announcing. The monthly force wipe schedule puts that in a calendar.

A worked example: switching a server to a custom map#

A 60-player community server on a procedural 3500 map wants a themed custom map for the next wipe.

1. A week before, buy or obtain the map and read its requirements: size, extension, plugins.
2. Upload harbour-v1.map to the web host and test the URL from a phone on mobile data.
3. On a test copy of the server, replace the three procedural convars with +server.levelurl and install the extension. Start, join, check monuments and spawns.
4. On wipe day, update Rust, update the extension, re-download the map if the maker released a fix and rename it harbour-v2.map.
5. Delete the old .sav and .map files, set server.levelurl on the live server, start.
6. Announce that the first join downloads the map so players are not surprised by a longer load.

Keep the old procedural settings written down. If the custom map fails at the last moment, switching back to a seed you previewed is a two-minute change.

Troubleshooting maps#

Players stuck on "Downloading map" or failing with a download error. The URL is not a direct download, has expired, or is rate-limited. Test it in a browser from outside your network.

Some players see old terrain. The file was replaced under the same name and their cached copy won. Rename and update server.levelurl.

The server fails to start after an update with a custom map. A prefab or extension changed. Check for a new map version and extension build; switch to a procedural map to get the server up while you wait.

Monuments with no NPCs or broken IO. The required extension is not loaded. Check the console at startup for the extension's load line.

The map looks different from the preview. The preview was made on a different game version or a different size. Confirm both match your server.

The first start after a wipe runs out of memory. Generation on a large world size. Reduce server.worldsize or give the generation run more memory.

FAQ#

What is the best world size for a Rust server?

The one that matches your peak population. 3000-3500 suits most community servers of 30-100 players; 4000 and above only pays off with more players than that.

Can I keep the same map between wipes?

Between forced wipes, yes: keep the .map, delete the .sav, and players start fresh on familiar terrain. After a forced update, a procedural seed usually generates a different map, while a custom map stays the same if its maker updates it.

What is the largest map Rust allows?

Procedural maps go up to a world size of 6000. Larger worlds are rarely a good idea: they spread players thin and cost far more memory and performance than they return.

Where do I get custom maps for a Rust server?

From map makers directly, or from marketplaces such as Lone.Design and Codefling, where paid maps usually include updates after game changes. Most are made in RustEdit.

Why can players not download my custom map?

Almost always the URL. It must return the file directly over HTTP or HTTPS, without a preview page, login or expiry. Host it somewhere you control and test it from another network.