One of the most important things in IoT system development is the right communication technologies and protocols. Communication of modern IoT systems can be divided into two main parts: device-to-cloud communication and communication between cloud microservices (application level). In this study, the authors designed a test-system environment for evaluating the performance of the existing transmitting protocols for the cloud microservices communication. The proposed environment allows emulate of IoT systems with low network latency which allows evaluating and comparing protocols performance. The authors provide tests for the most popular application-level protocols: HTTP, MQTT, AMQP, and GRPC. The performance evaluation was performed based on such metrics: throughput, concurrency, scalability, transmitting size, and init connection time. The obtained experimental results and testing environment can be used for the efficient design of microservice communication.