Representational State Transfer (RESTful) and Message Queues (MQ) are two different architectural approaches used in the context of building and designing distributed systems and communication between different services making up those distributed systems. If you are designing a distributed system based on the microservices architecture, then you will find yourself asking which of these 2 would suit that system better. In this short post, we will review the differences between the 2 and how each one suit a scenario over the other.
The basics about RESTful
- RESTful is an architectural style that provides guidelines for creating web services and APIs that are well-organized, scalable, and easy to maintain.
- It relies on standard HTTP methods like GET, POST, PUT, and DELETE to perform operations on resources.
- RESTful APIs expose resources as URLs, making them accessible through standard HTTP requests.
- REST is often used in scenarios where interactions between clients and servers are stateless, meaning each request from the client to the server must contain all necessary information for the server to understand and process the request.
- It is commonly used for building web applications, mobile apps, and other systems where simple communication patterns are sufficient.
The basics about MQ
- MQ are a communication pattern used in distributed systems to enable asynchronous communication between different components or services.
- In a message queue, messages are sent from a sender (in other words, producer) to a queue, and then the messages are consumed by one or more receivers (also known as consumers).
- MQ are designed to decouple components, meaning that producers and consumers don't need to know each other's existence or state.
- They provide a way to handle tasks that can be performed asynchronously and separately from the main application flow.
- MQ are often used in scenarios where there is a need for reliable, scalable, and asynchronous communication between different components, especially when one component cannot or should not wait for an immediate response from another.
The key differences
- RESTful relies on synchronous, request-response communication over HTTP whereas MQ provides asynchronous communication by allowing messages to be queued for later processing.
- RESTful interactions are typically stateless, where each request contains all the necessary information whereas MQ enables stateful communication, where messages can carry complex data and maintain state between components.
- RESTful is well-suited for scenarios where immediate responses are required, and interactions are relatively simple whereas MQ is ideal for scenarios where decoupling, asynchronous processing, and reliability are crucial, such as in large-scale distributed systems.
- RESTful APIs are generally easier to design and consume compared to setting up and managing MQ.
- RESTful communication tends to have lower latency since it's synchronous whereas MQ emphasizes throughput and scalability, making it suitable for scenarios where high volumes of messages need to be processed efficiently.
Which should you choose for your next distributed system(s) project?
In summary, the choice between RESTful and MQ depends on the specific requirements of your system. RESTful is best for simpler synchronous interactions, while MQ provide a robust solution for asynchronous communication and decoupling between components. In some scenarios, it will not come down to choosing between either as both can be used in the same project. A quick example of such scenario is where an internal API is set between two services or components while either need to connect remotely to a remote database, for which MQ would be better suited.