There 2 good alternatives that you can pick
1- Kafka
2- RabbitMQ
Also There are a lot of options for asynchronous integration. Some of the widely used ones are:
Kafka
RabbitMQ
Google Pub/Sub
Amazon Services
ActiveMQ
Azure Services
Also there is other good options for cloud options like Azure Service Bus or Amazon Kinesis for event streaming.
Ok, finally we finished to Async Microservices communications. But I would like to elaborate how message broker systems work and how they applied distributed pub/sub pattern with their topic structure.
So we should evolve our architecture with applying Async communication or Service Aggregator Pattern in microservices patterns in order to accommodate business adaptations faster time-to-market and handle larger requests.