---
title: "Device"
description: "A device is a printer, or a Printer Group, that a job can go to, as the PreForm API lists it."
url: https://developer.formlabs.com/core-concepts/device/
---

# Device

A *device* is a printer, or a Printer Group, that a print job can go to. Each printer
is identified by its *serial name*, such as `Form4-ExampleDevice`, in every Formlabs API.
PreForm lists both the printers on its local network and Dashboard printers/Printer
Groups (if logged in to a Formlabs account).

## How printers connect

PreForm and PreForm Server reach printers on the local network. Printers reach
Formlabs servers over the internet for Dashboard, remote printing, and firmware updates:

![Diagram of the connections between PreForm, Formlabs printers, and formlabs.com. PreForm sends print jobs and firmware updates to printers on port 35 over the local network. PreForm and printers reach api.formlabs.com, updates.formlabs.com, and gateway.formlabs.com on port 443 over the internet.](https://developer.formlabs.com/assets/images/support/connectivity-and-security-diagram.jpg)

*Connections between PreForm, printers, and Formlabs servers.*

A printer connects over USB, over a local network with no internet access, or over an
internet-connected local network. Remote printing and Dashboard need the printer on the
internet. For more information, see
[Connectivity and security](https://formlabs.com/support/Connectivity-and-Security/).

## List devices with the PreForm API

The `list_devices` method returns the same printers and Printer Groups that the
printer list on the PreForm **Job Setup** screen shows:

**SDK:**

```python
# Disconnected devices aren't listed.
for device in preform.list_devices().devices:
    print(device.id, device.product_name, device.status, device.ready_to_print_now)
```

**curl:**

**macOS:**

```bash
curl http://localhost:44388/v1/device/list/
```

**Windows:**

```powershell
curl.exe http://localhost:44388/v1/device/list/
```

Each record carries the device's `id`, its `product_name`, its `status`, and its
`ready_to_print_now` flag. A printer record also carries the `tank_material_code` of
the loaded resin tank, so code that routes orders across a fleet can pick a printer
that already has the right material. Disconnected devices aren't listed.

To search the network first, call the `discover_devices` method. For more information, see
[Manually adding a printer to PreForm](https://formlabs.com/support/Manually-adding-a-printer-to-PreForm/).

## What's next

- [Group](https://developer.formlabs.com/core-concepts/group.md)
- [Connectivity and security](https://formlabs.com/support/Connectivity-and-Security/)