How to arrange data exchange between several applications?

Question

Service Oriented Architecture

Given (this is all a test case not related to any real projects):
- web application "1" written in NodeJS, which has a service for obtaining TODO lists from the database
- web application "2" written in Java, which has there is a service for obtaining users from the database
- a web application "3" written in Python, which will request data from applications 1 and 2. It is
necessary:
​​- to implement communication between these applications
- at the same time, we do not want to use HTTP for communication. You can implement something like some kind of command-bus that will connect all these three applications, or there are some other interesting ways.
Your experience and practice in such architecture is interesting. I would be grateful for your advice and any reading material that will help to solve this problem.

Answer 1

Alternatively:
RabbitMQ