Choosing the Right Communication Protocol for Connecting Applications: A Comprehensive Guide

To connect three applications together, you can use one of the following protocols, depending on the type of applications and their specific requirements:

1. HTTP/HTTPS (RESTful API):

Ideal for web applications or backend services. Applications communicate via API by sending HTTP requests. Simple and easy to implement, but not suitable for real-time needs and often requires frequent polling.

2. WebSocket:

Used for applications that require real-time communication (e.g., chat, online gaming, instant notifications). WebSocket maintains a two-way connection between client and server, enabling instant data exchange without polling.

3. gRPC:

Well-suited for microservices, especially when high performance and cross-language communication are needed. gRPC uses HTTP/2, which is faster than HTTP/1.1 and supports streaming.

4. Message Queue (such as RabbitMQ, Kafka):

Suitable for asynchronous communication or when you need a channel to handle high event volumes. Applications send messages to a message broker, and other applications can receive these messages.

5. GraphQL Subscriptions:

If the applications use GraphQL and need real-time updates, GraphQL Subscriptions (often over WebSocket) is a good option.

6. SOAP (Simple Object Access Protocol):

Suitable if you need to communicate with systems requiring high security and services built on XML. Choose the protocol based on specific requirements such as performance, latency, security, and real-time functionality needed by your applications.