code: private void doDeployVerticle(final Message<JsonObject> message) {
      String main = message.body().getString("main");
      if (main == null) {
        message.reply(new JsonObject().putString("status", "error").putString("message", "No verticle main specified."));
        return;
      }
  
      JsonObject config = message.body().getObject("config");
      if (config == null) {
        config = new JsonObject();
      }
      int instances = message.body().getInteger("instances", 1);
      boolean worker = message.body().getBoolean("worker", false);
      if (worker) {
        boolean multiThreaded = message.body().getBoolean("multi-threaded", false);
        platform.deployWorkerVerticle(main, config, instances, multiThreaded, createDeploymentHandler(message));
      } else {
        platform.deployVerticle(main, config, instances, createDeploymentHandler(message));
      }
    }
docs: Deploys a verticle.