katoikia-app/servicio-notificaciones/src/main.ts

import { NestFactory } from "@nestjs/core";
import { Transport } from "@nestjs/microservices";
import { AppModule } from "./app.module";
import { Logger } from "@nestjs/common";

const logger = new Logger();

async function bootstrap() {
  const app = await NestFactory.createMicroservice(AppModule, {
    transport: Transport.TCP,
    options: {
      host: "127.0.0.1",
      port: 3009
    }
  });
  app.listen().then(() => logger.log("Microservice Notificaciones is listening" ));
}
bootstrap();