Installation
GRBL Server runs as a Windows desktop application that hosts a small web server on your local network. You install it on one computer per workshop — the host. There it opens in its own window, like any other desktop program. Other computers and laptops on the same network reach the same interface through a browser.
This page walks you through getting from the download link to a running server that other computers can reach.
Requirements
- Host computer: Windows 10 or 11, 64-bit. At least 2 GB of free RAM.
- Network: the host must be on the same Wi-Fi (or wired LAN) as any computer you want to control it from.
- Hardware: USB ports for serial controllers, or network reach for Wi-Fi (ESP32) and TCP controllers.
- Browser (only on the other computers): a modern browser. Chrome, Edge, Firefox, and Safari are all fine. The host doesn't need one — the app draws its own window.
Install steps
- Download the latest installer from the download page.
- Run the installer. It's digitally signed, so the Windows User Account Control prompt shows the verified publisher SISTEMAS TECNICOS CATALUNYA S.L — confirm to continue. On a brand-new build, SmartScreen may still show a "Windows protected your PC" notice while the fresh signature builds reputation; if it does, click More info, then Run anyway.
- Choose an install location (the default is fine). The installer creates a Start menu entry and a desktop shortcut.
- After install, launch GRBL Server from the Start menu.
- GRBL Server opens with the workspace ready to use. Nothing to type, no browser to open — the interface is right there in the app window.
- To use it from another computer as well, open Software Settings → Server inside the app. That page shows the address to type over there — the host's IP (for example
http://192.168.1.42) and agrblserver.localshortcut.
First launch checklist
The first time you start GRBL Server, three things should happen in order:
- You land on the Sign in page. Use the account you created on the GRBL Server website. See Login & accounts for the full flow.
- After signing in, the sidebar loads with Working, File Loaders, Configuration, Storage and Software Settings groups.
- Closing the window doesn't stop the server. The app keeps running in the notification area (next to the clock) so machines and any connected computers stay online. Right-click that icon and choose Quit when you really want to stop it.
Firewall & private network
On first launch, Windows usually shows a firewall prompt asking whether to allow GRBL Server to communicate.
- ✅ Allow it on Private networks so other computers on your Wi-Fi can reach the UI.
- ❌ You don't need to allow Public networks. GRBL Server is meant to be reached only from inside your local network.
If you missed the prompt or answered No, you don't have to hunt through Windows settings: open Software Settings → Server on the host and click Allow GRBL Server through the firewall. Windows asks for administrator permission once and the rule covers every network profile.
GRBL Server also tries to add a small firewall rule for the grblserver.local shortcut (mDNS, UDP 5353). Creating that rule needs administrator rights — running GRBL Server as administrator once lets it add the rule for every network profile. This is optional: the IP address works whether or not the rule exists.
Accessing the UI from other computers
Open Software Settings → Server on the host. That page shows the two ways to reach the server, and lists the computers currently using it — the surest sign that network access works. Open either address in a browser on any computer on the same Wi-Fi.
By IP address — recommended
Type the host's address exactly as the Server page shows it:
http://192.168.1.42Replace 192.168.1.42 with your host's IP. Most of the time that's the whole address — but if the Server page shows a port after the IP, include it too (see Port selection below). The IP address works on every computer, so this is the method to rely on.
By name — grblserver.local
So you don't have to memorise an IP, the server also answers to a fixed name:
http://grblserver.localAs with the IP, that's usually the whole address — add a port only if the Server page shows one after it.
It's the same interface whether you're looking at the app window on the host or at a browser tab on another computer — you're not running anything on the other computer, and it can set up and run jobs just the same.
Port selection
You normally never have to think about the port. By default GRBL Server picks one itself at startup, so it works out of the box even when other software on the host already occupies common ports. It tries these in order and takes the first that is free:
80— the standard web port; when this one is used, the address needs no:portsuffix at all.- then
5000,8080,8000,8888. - if every one of those is busy, a random free port chosen by Windows.
Whichever it lands on, the Server page shows the full address, and the grblserver.local shortcut always points at the same port.
Pinning a fixed port
If you need the server on a predictable port — for a bookmark, a firewall rule, or a router port-forward — you can pin one:
- Open Software Settings → Settings in the GRBL Server UI and select the APP section.
- On the port row, switch the toggle from Automatic to Manual and type the port you want.
- Save, then restart GRBL Server. The Server page shows the new port.
Updating to a new build
Updates aren't automatic yet. To update:
- Quit GRBL Server on the host: right-click its icon in the notification area and choose Quit. Closing the window on its own only hides it — the server keeps running.
- Download the new installer from the download page.
- Run the installer. It upgrades the existing installation in place — your machines, presets, workflows, and jobs are preserved.
Uninstalling
Remove GRBL Server through Windows Settings → Apps → Installed apps → GRBL Server → Uninstall. The uninstaller removes the application but keeps your data folder so you don't lose your setup if you reinstall later.