In account panel, you can find your droplets list. Click in the link to open droplet page and then check it URL. It should be something like this: https://cloud.digitalocean.com/droplets/XXXXX Where XXXXX is your droplet ID.

If you want to find the droplet ID programmatically, you can get a list of all active droplets with:

curl -X GET "https://api.digitalocean.com/v1/droplets/?client_id=$DO_CLIENT_ID&api_key=$DO_API_KEY"

The results will look like:

{
  "status": "OK",
  "droplets": [
    {
      "id": 100823,
      "name": "test222",
      "image_id": 420,
      "size_id":33,
      "region_id": 1,
      "backups_active": false,
      "ip_address": "127.0.0.1",
      "private_ip_address": null,
      "locked": false,
      "status": "active",
      "created_at": "2013-01-01T09:30:00Z"
    }
  ]
}

The "id" value is the droplet's id. If you just want to get the id, you need to parse the returned json. Our community has written a number of API wrappers in different programing languages that could be helpful here. Search GitHub for "DigitalOcean" and you'll see that there are hundreds of open source integrations using our API. Just about every language is covered. If you just want to parse it on the command line, take a look at the "jq" tool. On Ubuntu, you can install it with:

sudo apt-get install jq

You can use it parse json directly on the command line. To get just a list of droplet ids, run:

curl -X GET "https://api.digitalocean.com/v1/droplets/?client_id=$DO_CLIENT_ID&api_key=$DO_API_KEY" | jq ".droplets[] | .id"