How did the services interact with each other?

Services typically interact with each other through APIs, most often RESTful or gRPC. The interaction can occur over the HTTP/HTTPS protocol, where one service sends requests to another and receives responses. Message brokers such as RabbitMQ or Kafka are also used for asynchronous message exchange.

An example of interaction via REST API in Python using the requests library:

import requests

response = requests.get('http://service-b/api/data')
if response.status_code == 200:
    data = response.json()
    print(data)

Thus, services exchange data in JSON format or other convenient formats, ensuring modularity and scalability of the system.