Check if channel is live [C#, Discord]

You need to use C# to load (GET) a web URL - https://api.twitch.tv/helix/streams?user_login=lightstreak Replace lightstreak with the user you are interested in.
You need to set a Header with your Client-ID.

Then, when you load the URL, you will get a response in JSON format - this is why you need to parse JSON.

If the user is not online, you will get a response like this:

{
  "data": [],
  "pagination": {}
}

If the user is online, you will get a response like this:

{
  "data": [
    {
      "id": "28110269104",
      "user_id": "26490481",
      "game_id": "497078",
      "community_ids": [],
      "type": "live",
      "title": "FC5 PC First Playthrough - [ Follow @summit1g ]",
      "viewer_count": 25871,
      "started_at": "2018-03-28T19:29:14Z",
      "language": "en",
      "thumbnail_url": "https://static-cdn.jtvnw.net/previews-ttv/live_user_summit1g-{width}x{height}.jpg"
    }
  ],
  "pagination": {
    "cursor": "eyJiIjpudWxsLCJhIjp7Ik9mZnNldCI6MX19"
  }
}

Note that type is “live”