gSender: connect to and control grbl-based CNCs

gSender is a feature-packed CNC interface software designed to be clean and easy to learn while retaining a depth of capabilities for advanced users. Its development was begun in 2019 out of a passion for hobby CNC machines: an interface reimagined to suit the needs of the at-home CNC user.

• Totally free
• Accepts standard, grbl-compliant g-code from all the common CAM programs
• Designed to be generic so any standard grbl or grblHAL CNC will work
• Expands its UI to the needs of your CNC by recognizing what features it's capable of
• Works on as wide a range in computing systems as possible (low-end PC to RasPi, leveraging Electron)
• Used to be based on the popular CNCjs controller interface but has since been mostly re-written

Our core principals during development have been to:

1. Make any CNC feel easy to use no matter your previous experience
2. Substitute CNC jargon with simple language when possible
3. Keep the interface flexible to accommodate any common CNC machine
4. Maintain 'power tools' and customizability for advanced users
5. Prioritize interface reliability over new features
6. Otherwise continue pushing forward in any way possible to advance the CNC experience

💻 Download

gSender is available for the systems below and does not yet support headless Pi operation

| <br>Windows (x64) | <br>Mac (Universal) | <br>Linux (Intel) | <br>Linux (ARM) | <br>Pi (64 bit) | |-----------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------| | | | | | | | Available EXE | Available DMG | Available DEB | Available DEB | Available DEB |

Check out the latest releases here.

📦 Feature Highlights

• Grbl and grblHAL controllers supported with full imperial/metric compatibility
• Smart machine connection
• 4-axis digital readout (DRO) with manual value entry
• All-directional jogging with XY diagonals, jog presets, and incremental/continuous single-button handling
• Zero-setting and Go Tos (with safe height)
• 3D toolpath visualization (no machine connection required)
• Probing in any direction plus safe continuity detection ensures no broken cutting tools
• Built-in gadgets for stock flattening, stock rounding, XY squaring, axis movement tuning, firmware flashing, and more
• Responsive screen design and workspace customizations including light and dark themes
• File insight on load (feed range, spindle range, tools used, estimated cutting time, and overall, max, and min dimensions)
• Feed override and active job status indicators
• Fully exposed keyboard shortcuts for external keyboard/keypad control
• Gamepad support built-in for a variety of controllers
• Safe height movements - accommodates machines with or without endstops
• Homing cycle and quick-movement locations available for machines with homing hardware
• Full spindle/laser support via manual control widgets, active alerting, and live overrides
• Full mist/flood coolant support via manual control widgets and active alerting
• Macros buttons (rearrangeable) with enhanced macro variables and individually assignable keyboard shortcuts
• Lightweight mode reduces processing intensity on less powerful hardware or when running larger files
• Easy workspace swapping for more advanced jigging or alignment work
• Supports 4th and rotary axes, even on vanilla grbl devices by hijacking Y-axis movements
• Built-in wizards to handle tool changing even on vanilla grbl CNCs
• Start-from-line functionality to resume jobs part-way through in case of failure of abort
• Job outlining to see the rough bounds of your file before cutting
• Customizable g-code injection events
• Tooltips for data entry points
• Alarm warning explanations to better contextualize CNC errors
• Sleep management to keep PC awake during g-code sending
• Pre-built machine profiles, including:
  • LongMill
  • AltMill
  • Mill One
• Generic support for other machines, including:
  • Shapeoko
  • X-Carve
  • SainSmart/Genmitsu
  • FoxAlien
  • 3018 CNC & PROVer
  • OpenBuilds CNCs
  • Ooznest WorkBee
  • Nomad
  • Carvey
  • RatRig
  • Bulk-Man 3D
  • YoraHome
  • Two Trees
  • BobsCNC
  • CNC4Newbie
  • MillRight
  • Onefinity (running grbl-based controller), and more...

🎓 Documentation

All up-to-date documentation can be found here: https://sienci.com/gsender-documentation/

If you run into issues or have ideas on how to improve gSender, let us know on GitHub or on our User Forum.

📃 Example Files

If you'd like to test gSender's capabilities, there are several gcode files in the examples directory that can be downloaded and run locally.

💼 License

gSender is free software, provided as-is and available under the GNU GPLv3 license.

🥽 Compiling Yourself

You can both run gSender locally using the public code-base as well as compile it for use on other systems which aren't listed in the downloads. This can come in handy whether you're aiming to customize the application for your specific needs, test experimental features, or contribute to open source development of the gSender project. Read more on the process here: https://resources.sienci.com/view/gs-compile/.

Note: This guide is intended for users with some familiarity with command-line interfaces and software development environments. If you are looking to simply install gSender, please refer to the gSender Installation Guide.

🕣 Development History

<details> <summary>Expand to see all version notes</summary>

1.5.7 (January 8th, 2026)

• Fixed issue with start job shortcut not firing in some situations.
• Park shortcut now persists between sessions.
• Unlock button now has same logic as large Alarm unlock button for Alarm 10 and 17 where it will reset and unlock for you.
• Corner selection hidden for Z-only probe type.
• Squaring tool calculations for custom distances are now correct.
• Added support for Teensy boards in recognized devices.
• Error line reporting mismatch fixed.
• Stopping on start event codes should now correctly clear the planner and reset the board.
• Added cut depth validation to Surfacing tool.
• Auto-reconnect should work for Ethernet again.
• Added import/export functionality for gamepad profiles.
• Homing location now shows correctly on stats page.
• Fixed issue with terminal history order.
• Added new config option to run check on a file when it's loaded in.
• Fixed issue with rapid position shortcuts not memoizing positions.
• GRBL spindle max/min again correctly updates the eeprom on change.
• Config search behaviour updates to be more consistent with modified flag enabled.
• Probe shortcut no longer causes an erro