Get your base_url and auth_key from https://control.shelly.cloud/#/settings/user
Get devices IDs from each device, in Settings/Device informations.
$ cargo run -- --devices "temperature:<device_id1>" --devices "door:<device_id2>[:<name2>]" --auth-key <auth_key> --base-url https://shelly-001-eu.shelly.cloud [--format long,short,icons] [--unit C,F]
$ ~/.config/waybar/config
{
"custom/shelly": {
"exec": "shelly-waybar [--interval 30] --devices temperature:12345:Balcony --devices plug:67890 --auth-key <YOUR_AUTH_KEY> --base-url https://shelly-001-eu.shelly.cloud",
"return-type": "json",
"tooltip": true
}
}