# Privacy Policy — GRBLworks

**Last updated: 14 September 2026**

GRBLworks is a controller for GRBL-based CNC machines. This policy describes

exactly what the app does with data. It was written by going through the app's

permissions and code rather than adapted from a template, so the specifics

below are checkable against the app itself.

## The short version

GRBLworks does not collect, transmit, or sell any personal information. There

are no user accounts, no analytics, no advertising, no crash reporting, and no

third-party SDKs of any kind. The app makes no connection to any server we

operate, because there isn't one.

Everything the app stores stays on your device.

## What the app stores on your device

The following is kept in the app's own private storage and never leaves your

device unless you move it yourself:

- **G-code files**: any file you open, upload wirelessly, or edit and save

  inside the app, in the app's private files directory. A file picked

  through the system file picker is copied into this same storage too, so

  it's still there — in the same Files list — the next time you open the

  app, not just for the session in which you picked it.

- **Machine settings you save**: machine profiles, macros you write, height

  maps from auto-levelling, surfacing wizard parameters, touch-plate

  thickness and tool diameter, which axes you've confirmed have a limit

  switch and whether each is Normally Open or Closed, and interface

  preferences (streaming mode, swipe-to-change-tab, start-with-the-computer).

- **Job recovery data**: the name and line number of a job that was

  interrupted, so it can be resumed. Cleared when the job finishes.

Uninstalling the app removes all of it. There is no cloud backup and nothing

to delete from a server.

## The wireless file server — please read this part

The app includes an optional file server so you can drop G-code onto the

device from a computer's browser over your local network.

**It is switched off when the app starts** and stays off until you turn it on.

Nothing is listening on your network unless you choose it.

**This server has no password.** Anyone on the same network who reaches the

address can list, upload, download, and delete files in the app's G-code

folder. That is the whole point of the feature, but it means you should

only run it on a network you trust — your home or workshop Wi-Fi, not a

café or a shared public network.

The server is limited to the app's own G-code folder and cannot reach other

files on your device. It is reachable only from your local network, never from

the internet, and nothing it holds is sent anywhere else.

The **SERVER** button on the Run tab turns it on and off. While it is off, no

port is open and the device is not announced on the network at all.

## Permissions and why each one is needed

| Permission | Why |

| --- | --- |

| USB host | To talk to your CNC controller over a USB OTG cable. This is the app's core function. |

| Internet, network state | For the local file server: opening a socket for it and finding the device's own address on your Wi-Fi network. The app makes no outbound internet connections of its own. |

| Change Wi-Fi state | Not used to change your Wi-Fi directly — it's one of a handful of permissions Android itself requires at least one of before the app's background-job service is allowed to start on newer Android versions. Declared for that reason alone. |

| Foreground service (connected device) | So a cutting job keeps running when the screen turns off, another app is opened, or a call comes in. Interrupting a job partway through ruins the workpiece. |

| Wake lock | Same reason: to stop the device sleeping mid-job. |

| Notifications | To show job progress and to tell you when a job finishes or stops. |

| Display over other apps | For the optional floating progress window, so you can watch a job while using another app. This is optional and off until you enable it. |

The app requests no access to contacts, location, camera, microphone, photos,

or any other personal data, because it has no use for any of it.

## Children

GRBLworks is a CNC tool.

It collects no data from anyone, including children.

## Changes to this policy

If this policy changes, the updated version will be published at the same

address with a new date at the top. Since the app collects nothing, any change

is likely to be a clarification rather than a change in practice.

## Contact

Questions about this policy or about how the app handles data:

**droidforks@gmail.com**

*(Replace this with the contact address you register with Google Play. Google

requires a working address here.)*