Blueprint Share

Send blueprints, blueprint books, deconstruction planners, and upgrade planners between two Factorio instances on the same machine, over localhost UDP. Handy when running a regular save and a map editor side-by-side.

Requires Factorio 2.0 or newer.

Quickstart

Two-way sharing between a Steam copy and a second standalone copy:

Get a second copy. Steam runs only one instance at a time. Download a standalone build of the same version from https://www.factorio.com/download (free for anyone who owns Factorio) and extract it outside the Steam install.

Windows: grab the ZIP package, not the installer. The installer shares %APPDATA%\Factorio with the Steam copy, so only one can run at a time.
Use port 25001 for the Steam copy and 25002 for the standalone. Change them only if another app is already using those ports.
Set the launch flag on each copy so it listens on its own port:
- Steam copy - right-click Factorio -> Properties -> Launch Options, enter --enable-lua-udp=25001.
- Standalone (Linux) - launch from a terminal as ./factorio --enable-lua-udp=25002.
- Standalone (Windows) - create a shortcut to bin\x64\factorio.exe and append --enable-lua-udp=25002 to the Target field. Or launch from a terminal: factorio.exe --enable-lua-udp=25002.
- Standalone (macOS):
  - Put factorio.app in its own folder, e.g. ~/Applications/Factorio-Standalone/.
  - Create a config.cfg next to it with the contents below, or download the ready-made macos/config.cfg from this repo:
    ; version=13
    [path]
    read-data=__PATH__executable__/../data
    write-data=__PATH__executable__/../../../factorio-data
  - From that folder, run open ./factorio.app --args -c "$PWD/config.cfg" --enable-lua-udp=25002 (the -c path must be absolute). Factorio will create factorio-data/ alongside factorio.app for saves, mods, and config.
On the standalone, set Mod settings -> Per player -> Blueprint Share -> Destination port to 25001. The Steam copy needs no change - its default already points at 25002.

One-way only: Only the receiver needs the launch flag. The sender just needs Destination port pointing at the receiver's listening port.

Usage

Ctrl + B - Send the blueprint, book, or planner currently in your cursor (or picked up from the blueprint library).
Ctrl + R - Manually receive. With Auto-receive on (default) incoming blueprints land in your cursor automatically. Use the hotkey in the Map Editor or when Auto-receive is off.

Settings

Settings live under Mod settings -> Per player -> Blueprint Share.

Setting	Default	Description
Destination port	`25002`	UDP port to send to. Must match the other instance's `--enable-lua-udp=<port>`.
Auto-receive blueprints	`on`	Automatically place incoming blueprints in the cursor. Disable if you prefer to trigger imports with the hotkey.
Log level	`Info`	In-game message verbosity. `Quiet` hides all messages. `Debug` shows full diagnostics. The mod log file always records full output.

Limitations

Localhost only. No LAN or internet sharing - Factorio binds UDP to 127.0.0.1.
Packet size ≈ 65 KB. Very large blueprint books can exceed the UDP limit and fail to send. Split the book or trim unused blueprints.
Map Editor. Auto-receive needs the simulation running. The editor is paused by default, so either unpause (Tools -> Time -> Speed -> Play) or use Ctrl + R to receive manually.
Headless servers. Receiving is disabled when no players are connected.

Troubleshooting

Invalid payload. - The other instance sent a packet the mod couldn't decode. Usually means a different, unrelated process is sending UDP to your port. Change the port.
Blueprint is too large. - The serialised blueprint exceeds the UDP limit. Send a smaller book.
Could not send... - The OS rejected the send. Check that the destination port is valid and that no firewall rule is blocking localhost UDP.
Version mismatch warning - The other instance is on a different Factorio version. Minor differences usually import fine, major versions may fail with Import failed.
Import failed. - The payload arrived but couldn't be imported into the cursor. Usually a Factorio version mismatch between sender and receiver.
Blueprint is in preview. - The library blueprint hasn't finished syncing with the server. Wait for the sync and resend.
Nothing happens on receive - Confirm the destination instance was launched with --enable-lua-udp=<port>.
Two copies fighting over the same saves/mods/config - Both installs share the same user data directory. You may see Couldn't create lock file Factorio\.lock: 32 Is another instance already running? when starting the second copy. See the Factorio Wiki for per-platform write paths and how to make a copy portable.

License

MIT