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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.
  • Machines: laser engravers and cutters running GRBL (connected by USB) or GRBL-ESP32 / FluidNC (connected over Wi-Fi or Ethernet). See Connections & firmware.
  • Network: the host must be on the same network (Wi-Fi or wired) as the computers you want to use it from, and as any Wi-Fi controllers.
  • Browser (only on the other computers): a modern browser — Chrome, Edge, Firefox or Safari. The host doesn't need one; the app draws its own window.

Install steps

  1. Download the latest installer from the download page.
  2. 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.
  3. Choose an install location (the default is fine). The installer creates a Start menu entry and a desktop shortcut.
  4. After install, launch GRBL Server from the Start menu.
  5. GRBL Server opens straight into its interface, in its own window. Nothing to type, no browser to open.
  6. To use it from another computer as well, open Network access in the sidebar (next to About). It shows the address to type over there — the host's IP (for example http://192.168.1.42) and a grblserver.local shortcut.

First launch checklist

The first time you start GRBL Server:

  1. GRBL Server opens on Home — it's free, so there's no account to create and nothing to activate. Until your first job has run, three steps across the top walk you through it — add your machine, create a job, run it — with a button for the next one.
  2. The sidebar holds Home, Library, Activity and Jobs, then a Setup group (Machines, Engraving profiles with Start & end G-code and Macros, Job templates) and an Automation group (Workflows). Settings, Network access and About sit at the bottom. The New job button at the top is available from every page.

Starting GRBL Server a second time brings the existing window back instead of starting a second copy.

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 network can reach the interface.
  • ❌ 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 Network access on the host and click Allow GRBL Server through the firewall. Windows asks for administrator permission once and the rule covers every network type. The page tells you whether the rule is in place.

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.

Network access: using it from other computers

Open Network access on the host. That page shows the address to type into a browser on another computer on the same network, and lists the computers connected — every computer that has loaded a page in the last few minutes, which is the surest sign that network access works.

By IP address — recommended

Type the host's address exactly as the Network access page shows it:

http://192.168.1.42

Replace 192.168.1.42 with your host's IP. Most of the time that's the whole address — but if the 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. If the host has more than one network address, use the one on the same network as the computer you're connecting from.

By name — grblserver.local

So you don't have to memorise an IP, the server also announces a fixed name:

http://grblserver.local

As with the IP, that's usually the whole address — add a port only if the page shows one. The name always points at the port the server actually started on.

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:

  1. 80 — the standard web port; when this one is used, the address needs no :port suffix at all.
  2. then 5000, 8080, 8000, 8888.
  3. if every one of those is busy, a random free port chosen by Windows.

Whichever it lands on, the Network access page shows the full address. Because the automatic port can differ after a restart, the page warns you when a saved bookmark might break.

Pinning a fixed port

If you need the server on a predictable port — for a bookmark or a firewall rule — you can pin one:

  1. Open Settings → General.
  2. On the port row, switch from Automatic to Manual and type the port you want.
  3. Save, then restart GRBL Server. Network access shows the new port.

Updating to a new build

Updates aren't automatic yet. To update:

  1. 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.
  2. Download the new installer from the download page.
  3. Run the installer. It upgrades the existing installation in place — your machines, engraving profiles, job templates, workflows, Library 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 so you don't lose your setup if you reinstall later.

What's next

Something unclear or wrong on this page? Contact support — these docs improve fastest from real questions.