How to communicate between two applications?

Question

JavaScript

Are there any out-of-the-box implementations for communication between two applications?
Now the situation is as follows:
1) There is a main application for working with logic and processing all information
2) There is an additional application that should receive requests from the main one, make a request to a third-party API, receive a response and return to the main application.

Answer 1

REST, SOAP

Answer 2

just worth reading the basics of microservice architecture and approaches to its implementation
in your case, any message broker will be a convenient solution, look at RabbitMQ