ControllerClient.cs

using System;
using BestHTTP.WebSocket;
using UnityEngine;

public class ControllerClient : MonoBehaviour
{
    private WebSocket webSocket;

    public class Query
    {
        public int id;
        public string type;
        public string query;
    }

    void Start()
    {
        // webSocket = new WebSocket(new Uri("ws://127.0.0.1:4000/"), "", "-H Sec-Websocket-Protocol: graphql-ws");
        // This one works ^

        webSocket = new WebSocket(new Uri("wss://us1.prisma.sh/andres-v/hello-world/dev"), "", "-H Sec-Websocket-Protocol: graphql-ws");
        // This doesn't work, the websocket doesn't even open

        webSocket.OnOpen += OnWebSocketOpen;
        webSocket.OnError += OnWebSocketError;
        webSocket.OnMessage += OnWebSocketMessage;

        webSocket.Open();
        Debug.Log($"Socket Open() at {Time.time}");
    }

    private void OnWebSocketOpen(WebSocket webSocket)
    {
        Debug.Log($"WebSocket Open! {webSocket.State}");

        var query = new Query();
        query.type = "init";

        var jsonData = JsonUtility.ToJson(query);
        Debug.Log($"{jsonData} at {Time.time}");
        webSocket.Send(jsonData);
    }

    private void OnWebSocketError(WebSocket webSocket, Exception ex)
    {
        Debug.Log("WebSocket Error!");

        error += ex.TargetSite;
        // Debug.Log($"{ex.Message} at {Time.time}");

    }

    private void OnWebSocketMessage(WebSocket webSocket, string message)
    {
        Debug.Log($"WebSocket message: {message} at {Time.time}");
        var response = JsonUtility.FromJson<Query>(message);

        if (response.type == "init_success")
        {
            var subQuery = new Query();
            subQuery.id = 1;
            subQuery.type = "subscription_start";
            subQuery.query = "subscription { messages { id content created } }";

            var jsonData = JsonUtility.ToJson(subQuery);
            Debug.Log($"{jsonData} at {Time.time}");
            webSocket.Send(jsonData);
        }
    }
}