How can you choose the best communication style for your microservices?

1 Synchronous communication

Synchronous communication means that the sender and the receiver of a message are both online and waiting for a response. For example, when you make a HTTP request to a microservice, you expect a HTTP response within a certain time frame. Synchronous communication is simple, easy to implement, and suitable for scenarios where you need immediate feedback or consistency. However, it also has some drawbacks, such as coupling the microservices, creating dependencies, increasing latency, and reducing availability. If one microservice fails or becomes slow, it can affect the whole system.

2 Asynchronous communication

Asynchronous communication means that the sender and the receiver of a message are not online at the same time, and the sender does not wait for a response. For example, when you publish a message to a message broker, such as Kafka or RabbitMQ, you do not expect a reply from the subscribers. Asynchronous communication is more complex, but also more flexible, scalable, and resilient. It decouples the microservices, reduces dependencies, improves performance, and allows for event-driven and reactive architectures. However, it also has some challenges, such as handling errors, retries, timeouts, ordering, and consistency.

3 Hybrid communication

Hybrid communication means that you use a combination of synchronous and asynchronous communication styles, depending on the context and the requirements of your microservices. For example, you can use synchronous communication for user-facing requests that need immediate feedback, and asynchronous communication for background tasks that can be processed later. Hybrid communication allows you to leverage the benefits of both styles, while mitigating the risks. However, it also adds more complexity and requires more coordination and testing.

4 Best practices

When selecting the most suitable communication style for your microservices, you must take into account the trade-offs between simplicity, performance, reliability, scalability, and consistency. To help make better decisions, it is advised to design your microservices with clear boundaries and contracts, favoring asynchronous communication over synchronous communication whenever possible. However, synchronous communication should be used when immediate feedback or strong consistency is required. Hybrid communication can also be used to balance different requirements and scenarios. Additionally, suitable tools and protocols should be employed for the chosen communication style, such as HTTP, gRPC, or GraphQL for synchronous communication and message brokers, event buses, or streams for asynchronous communication. Error handling, retry, timeout, and fallback mechanisms should also be implemented to increase reliability and availability of your microservices. Lastly, monitoring and tracing your communication will assist in identifying and troubleshooting issues as well as measuring performance and optimizing your communication. In conclusion, by understanding the advantages and disadvantages of different communication styles and applying best practices, you can create more resilient, efficient, and maintainable microservices architectures.

5 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?