How Microservices Communicate with Each Other

Ways that Microservices Communicate

The scalability and modularity of microservices make them a great architecture for platforms and apps with many moving parts. However, these separate parts do need to communicate with each other for the platform or app to be functional. It’s a unique challenge that can be solved with several different communication protocols. But what are these communication methods, and how do they work?

In this blog, we’ll explore the various ways microservices can interact with each other. We’ll go over some of the most common microservices communication protocols and give you some tips for testing and debugging those protocols. By the end of this blog, you’ll have a better understanding of how to integrate your microservices effectively.

Common Protocols Microservices Use in Communication

Some of the most common protocols microservices use in communication are API calls, Google remote procedure calls, and message brokers. Let’s get more familiar with each of these protocols so you can determine which should be used in your microservices architecture.


REST API calls are common methods of microservices to communicate. REST API calls enable microservices to share data and functionality, which allows microservices to work together seamlessly. In order to make a call, a microservice will need to know the endpoint of the called REST API and have the authentication to access this data or information. After the calling service sends the request, the called service will process it and provide a response.

If developers need to test REST API calls functionality and debug them, they can utilize tools like Postman, Cucumber, and k6. Microservices testing tools like Signadot can also integrate seamlessly with these tools, allowing you to easily test these protocols in isolation.


gRPC, or Google Remote Procedure Call, is another high-performance protocol that enables microservices to effectively and efficiently communicate. It typically works with protocol buffers to define the interface and serialization format. A key benefit of using gRPC is that it supports bi-directional streaming. In other words, it allows both the client and the server to send multiple messages asynchronously. This is ideal for situations where real-time data processing or frequent updates are required for an app or platform’s functionality. 

gRPC is also a highly scalable communication protocol that provides strong support for service discovery and load balancing. It is also easy to integrate with container orchestration platforms like Kubernetes. Additionally, it supports multiple programming languages such as Python, Java, Go, and many more. This makes it more flexible and enables developers to adopt it regardless of their preferred programming language.

Developers who need to test and debug gRPC protocols in microservices architecture can turn to tools like gRPCurl, gRPC GUI Clients, and Protobuf Inspector.

Message Brokers

Message brokers are another ideal solution for facilitating communication between microservices. Unlike traditional API calls or gRPC, message brokers work by providing a decoupled approach to communication

In short, a message broker acts as a middleman who receives messages from one service and delivers them to another. You can view message brokers as a central hub that allows services to publish messages, which other services ‘subscribe’ to, without the initial service needing to know what services it is publishing messages to. This decoupled approach allows services to operate more independently. 

Message brokers also use message queues or publish-subscribe patterns to make message delivery reliable, even in cases when services are unavailable or experiencing high load. In this case, message brokers can simply store messages until they are ready to be processed by the microservices that subscribe to them.

Some popular message broker technologies include Apache Kafka, RabbitMQ, and ActiveMQ. Each has its own unique features and strengths, allowing development teams to choose the most suitable solution for their microservice architecture. These message brokers typically have built-in tools for debugging and testing microservices communications.

Ways Signadot Can Help

If you’re looking for tools that can help you with testing communication between microservices in Kubernetes, Signadot is your ideal solution. Signadot enables developers to easily create Sandbox environments for each Pull request, giving them a safe and isolated environment to test and develop communication protocols. Our sandboxes support both REST and gPRC protocols. Additionally, we allow for isolated testing of services that communicate with message queues like Kafka. Some of the other key benefits of Signadot include:

  • Focused testing - With Signadot, developers can spin up only the changed services and dependencies to save valuable time and computational resources. Rather than running your entire application for testing, developers can focus on testing and developing these specific services and their communication protocols.
  • Comprehensive API testing - Signadot seamlessly integrates with API testing tools like Postman, Cucumber, and k6. This allows developers to run through API tests in a Sandbox environment, ensuring all services can effectively communicate with each other. Our sandboxes can also be used with REST API and gPRC testing tools such as Postman, Apigee, SoapUI, Insomnia, Swagger UI and more.
  • End-to-end testing - Signadot also enables full end-to-end testing, integrating with tools like Selenium and Cypress to target multiple Sandboxes at once. Developers know how crucial end-to-end testing is for communication protocols, and Signadot will significantly speed up and simplify this testing phase, which ultimately speeds up the software development cycle. With isolated testing of new features and protocols, you don’t have to worry about impacting the overall performance of your platform when you need to conduct a new test.

In short, Signadot is an invaluable tool for microservice communication. With features for Sandbox creation, API testing, end-to-end testing, and more, you can ensure seamless integration and functionality of your microservices. If you’re interested in learning more about Signadot and the various microservices testing features we offer, click below to learn more.

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