Manage your fleet

Artemis is a fleet management system for ESP32 devices running the Toit platform. It connects your devices to the cloud and makes it possible to seamlessly update the firmware, containers, and configurations that run on your devices. It is free for up to ten devices and built to scale.

Artemis is the combination of an on-device service that communicates with a broker in the cloud and the developer tooling to help orchestrate the devices. It is possible to host your own broker, so all your data and code remains under your control.


On your development machine, Artemis is a single command line tool (artemis). You can download it from here:

If you download an archive, you should unpack it and put the embedded artemis or artemis.exe binary somewhere on your PATH. The same applies when you extract the artemis binary from the macOS artemis.dmg file.

The Artemis command line tool is a standalone executable written in Toit. Use artemis help for usage help.


Artemis needs git to be installed on your system. On most macOS and Linux systems, git is already installed. On Windows, you can download and install git from

Signing up and logging in

All users must be authenticated. For OAuth-based authentication you can just sign up and log into Artemis as follows:

artemis auth login --provider=github


artemis auth login --provider=google

Alternatively, for email-based authentication, sign up with:

artemis auth signup --password=PASSWORD

Then, after having confirmed the email address, log in with:

artemis auth login --password=PASSWORD

Usually, signing up by OAuth is more convenient, but email-based authentication can be useful if you want to have multiple accounts. For example, with Google domains anything after the "+" is discarded. So is an alias for

Creating an organization

Every device must belong to an organization. You can create as many organizations as you want (and there will eventually also be a way to remove them again). You can add an organization using artemis org add like this:

artemis org add "My Organization"
artemis org show
artemis org members list

The artemis org show command shows you your organization ID, which is a UUID.

Once you create a new organization it is automatically set as default. You can switch to a different organization with artemis org default YOUR-ORG-ID, or by passing the organization id to the commands that need one.

You can add other users to your organization with artemis org members add THEIR-USER-ID. The user you want to add can find THEIR-USER-ID with artemis profile show.

If you want to, you can also change the name in your profile with:

artemis profile update --name "My full name"

Getting started

Once you've downloaded the command line tool (artemis), signed up, and created an organization, you're ready to put Artemis on a device and manage it via the cloud.

First steps

Artemis manages fleets of devices. To get started, first you must create an empty fleet in a suitable directory. Go to the directory and run:

artemis fleet init

This creates three files: fleet.json, devices.json, and my-pod.yaml. The fleet.json file holds some metadata and the list of devices in devices.json is empty. The my-pod.yaml file is the most interesting to get started.

Artemis lets you describe the functionality and configuration of your devices in pods, which is a set of containers and the configuration of the environment they need to run in. Pods can be specified through version control friendly specification files, so let's start with the simplest possible specification by putting the following content into the my-pod.yaml file:

# yaml-language-server: $schema=

name: my-pod
sdk-version: v2.0.0-alpha.158
artemis-version: v0.20.1
max-offline: 0s
  - type: wifi
    ssid: YOUR WIFI SSID
    password: YOUR WIFI PASSWORD
containers: {}

The first line is a comment and not required. It helps vscode to find the correct schema for the file. If the yaml extension is installed, you will get code completion and diagnostics this way.

If you fill in your WiFi credentials, you have a working specification for a pod named my-pod. To make the pod available to your fleet, you will need to upload it to your broker:

artemis pod upload my-pod.yaml

This uploads my-pod and gives is a few useful tags, so we can find it later. The fleet has a default group of devices and in the fleet.json file, we can specify that the group uses my-pod@latest as its pod. Whenever we upload a pod, its latest tag is automatically updated, so it can be convenient to just refer to that from the group:

  "groups": {
    "default": {
      "pod": "my-pod@latest"

Instead of using the convenient latest tag, it is often preferable to use tags that do not change in the fleet.json file. This makes it possible to reproduce and reason about the fleet state at any revision of the fleet.json file. So instead of using my-pod@latest, you can use a stable tag like my-pod@v1.0.2 or my-pod@20230515175710-broad-method.

To get your functionality onto your device, you flash a device with firmware my-pod@latest by running:

artemis serial flash --port /dev/ttyUSB0

This flashes the device over the USB serial port and puts both the Toit platform and the Artemis service onto the device. Once flashed, you can follow the behavior of your device by monitoring the serial port using something like jag monitor (included with Jaguar). It shows something like this:

configsip: 0, SPIWP:0xee
mode:DIO, clock div:2
ho 0 tail 12 room 4
entry 0x400805c4
[toit] INFO: starting <v2.0.0-alpha.69>
[toit] INFO: using SPIRAM for heap metadata.
[artemis] INFO: starting {device: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}
[artemis.scheduler] INFO: job started {job: synchronize}
[artemis.synchronize] INFO: connecting
[wifi] DEBUG: connecting
[wifi] DEBUG: connected
[wifi] INFO: network address dynamically assigned through dhcp {ip:}
[wifi] INFO: dns server address dynamically assigned through dhcp {ip: []}
[network] INFO: opened
[artemis.synchronize] INFO: connected to network
[artemis.synchronize] INFO: connected to broker
[artemis.synchronize] INFO: synchronized

Once you see that the device succesfully connect to the cloud, you should be ready to check its state:

artemis device show

Artemis also added your device to your fleet as part of running artemis serial flash, so you can now check the status of your entire fleet by running:

artemis fleet status

Great! With a little help from the Artemis service and developer tooling, you have a cloud-managed device capable of running high-level code.

Tinkering with your device

Artemis allows you to change and tinker with the current state of a device without requiring a full firmware update. This makes it possible to change the behavior of a device by adding new functionality (drivers or applications) or by changing configurations.

Such incremental changes are great for development; especially as they are faster to get onto the device and do not even require restarting the device. However, these changes are lost at the next firmware upgrade.

Controlling synchronization

Devices managed by Artemis need to connect to the cloud to receive updated information. The frequency at which they synchronize can be configured by the user.

Devices that connect frequently or all the time are easy to interact with and manage, but they spend a lot of power on staying connected all the time. The pod specification in the example my-pod.yaml does not specify how often to connect, so Artemis assumes that you want an interactive device.

If you don't need your device to stay connected all the time, you can give it a 'max-offline' setting. This tells the Artemis service that it is okay to be offline for 5m, 1h30m, or 24h without necessarily connecting to the Internet.

You can set this through:

artemis device set-max-offline 1m19s

If you monitor the output of your device, you'll see that the device goes to sleep between its cloud synchronizations.

You can go back to the original setting, where the device tries to stay online all the time by giving it a 'max-offline' setting of 0s:

artemis device set-max-offline 0s

Installing code

Artemis makes it easy to install and uninstall new code on your devices. The code that you install runs in containers, so they are isolated from the rest of the system and can be started and stopped independently of the other parts of the system.

To install new code on your device, you can install a new named container based on a Toit source file:

artemis device container install hello hello.toit

The container name hello does not have to match the source file name hello.toit and you will use the container name to refer to the installed container later. There can only be one container with a given name on a device, so installing another one will replace the original.

By default containers will run when installed and whenever the device boots, but you can control this behavior by specifying the triggers on the command line. If you only want to run when booting, you can do:

artemis device container install --trigger boot hello hello.toit

You can also get Artemis to run your containers on a schedule by triggering them at a specified interval. As an example, you can install the hello container and get it to run every 10s like this:

artemis device container install --trigger interval:10s hello hello.toit

Any arguments you pass to artemis device container install after the source file will be passed as string arguments to main. If you put this in args.toit:

main args:
  print "arguments = $args"

and run:

artemis device container install args args.toit foo bar

you should see arguments = [foo, bar] printed.

Finally, you can always uninstall a container again using:

artemis device container uninstall hello
artemis device container uninstall args

Updating a single device

If you want to update to a new version of the Toit SDK or benefit from the latest Artemis release, you can do an over-the-air firmware update. Such updates are pushed to the broker in a compressed form and picked up by the device.

Similar to artemis serial flash, the over-the-air update command also uses pods, so the common workflow is to change your pod specification file to reflect the state you want your device in, and then update it to that through:

artemis pod upload my-pod.yaml
artemis device update my-pod@latest

You can specify which device to update using a device-id flag (-d), but most of the time you just use the default ID that was either set during flashing, or that can be set with artemis device default.

Rolling out changes to a fleet

If you've modified the my-pod.yaml file and you want to make the changes available to your fleet of devices, you can upload the latest version of your pod using:

artemis pod upload my-pod.yaml

If your fleet.json uses my-pod@latest, you can ask the fleet to roll out the changes to your devices using:

artemis fleet roll-out

If you changed the pod reference in fleet.json to use a stable tag, then you need to update that before you run artemis fleet roll-out:

artemis fleet group update --tag v1.0.3

Because your pods encapsulate the fully configured firmware, this makes it easy to upgrade your containers, the Artemis service, and even the Toit SDK and its associated virtual machine.