What interfaces are suitable for application coupling?

Question

Currently I'm investigating solutions for making an application usable from other applications. I.e. I want to give other applications control over my application's internals (request current state and other information, trigger actions etc.).

So far I found three viable solutions:

• Provide a COM Server
• Provide a web server with a rest interface
• Provide a SOAP server

Are there any other possibilities that

• rely on standardized technologies
• work with commonly used programming languages and frameworks
• are easy to use (by the consumer as well as me, the developer)

Answer 1

In my opinion, using a web server with a rest interface would be the easiest option for 3rd parties to connect to your application.

You can also use something like Swagger to make it even easier for other parties to use your application, since you would be providing a client (albeit, raw) yourself.