Best Factorio Mods for Multiplayer Servers in 2026

The mods that matter on a Factorio server are the ones that do not cost UPS. Factorio runs its whole simulation on one thread at 60 UPS, and that number, not RAM, is what decides whether a multiplayer game feels smooth. A mod that scans every entity each tick is cheap in an hour-old base and expensive in a 200-hour one.

That is the filter for everything below: what does it cost per tick, and does every player need it installed too.

Before the list: what actually breaks a Factorio server

UPS is the bottleneck, not memory. A fresh vanilla save uses roughly 300 to 500 MB. Most real factories run inside 2 GB. Megabases and heavy overhauls reach 4 GB, and Space Age with several active planets reaches 6 to 8 GB, because every surface being simulated carries its own entity and chunk memory.

Player count matters less than factory age. A two-player server running for 200 hours will usually need more than a fresh ten-player one. Valheim behaves the same way, and for the same reason: one thread doing the simulation.

Every player needs the same mods at the same versions. Factorio checks this at join and refuses a mismatch, which is a feature: it prevents desyncs. It also means a 200 MB modpack is a 200 MB download for anyone new, so the size of your list is a real barrier to people joining.

Quality of life, effectively free

These change how the game feels without touching the per-tick cost in a way you can measure.

• Squeak Through. Walk between buildings instead of around them. Costs nothing at runtime and removes the single most common irritation in a shared base.
• Even Distribution. Split items evenly across a row of machines by dragging. Purely client-side convenience.
• Bottleneck Lite. Coloured indicators on machines that are starved or blocked. Diagnostic, and the "Lite" version exists precisely because the original was heavier.
• Text Plates. Label things. On a multiplayer server, where somebody else built the thing you are trying to understand, labelling is worth more than it sounds.

Logistics and blueprints, cheap enough

• Blueprint Sandboxes. Design in a separate editor surface rather than cluttering the main map. Note that an extra surface has its own memory cost.
• Factory Planner or Helmod. Ratio calculators. Interface work, effectively no tick cost.

The ones to think twice about

Not bad mods. Mods with a cost worth knowing before a server of six people commits to them.

• Overhaul packs such as Space Exploration or Krastorio 2. They are the reason to run a server, and they multiply entity counts, memory and UPS load. Budget 6 to 8 GB and expect a modpack download in the hundreds of megabytes.
• Train logistics mods. Many scan every train or every station on an interval. That is invisible at ten trains and noticeable at three hundred.
• Anything that scans all entities on a tick. The description rarely says so. The signal is a mod that reacts to things happening anywhere on the map rather than where a player is standing.

Choosing a list for a server, not for yourself

• Agree the list before the map is generated. Adding an overhaul to a running save is where things break; removing one is worse.
• Keep the download small enough that people actually join. Every megabyte is friction for a new player.
• Add mods in small batches so that when UPS drops you know what caused it.
• Back up before every change. Ours run automatically and restore from the panel. The same batching discipline keeps Garry's Mod servers diagnosable.

Our Factorio server hosting installs mods from the panel and keeps automatic backups, so trying a pack and rolling it back is a two-minute job rather than an evening.

When not to bother with a server

If two of you play at the same time and neither minds the game only running while the host is online, Factorio's built-in multiplayer is enough and free. A dedicated server earns its cost when the factory should keep running while you sleep, or when the save has become something you would genuinely mourn.