by Jeremy H
• April 20, 2020
The differences between microservices and web services deal with different concepts in modern application design. A microservice is a small, independent, application that performs a highly focused service as well as possible. A web service is an internet-based interface that makes the “services” of one application available to applications running on different platforms.
Since microservices are one of the most popular concepts in application development right now, they’re getting a lot more attention than web services. However, both concepts are highly relevant when building a modular, services-oriented application architecture – so it’s important to understand how both fit into the picture of modern app design.
In this article, we’ll use the following sections to explore the differences, advantages, and disadvantages of microservices and web services:
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In the simplest of terms, microservices and web services are defined like this:
Both microservices and web services can be used to build application architectures. Here’s a brief description of both architectural styles:
It’s common for modern, services-oriented application architectures to include a mix of microservices and monolithic applications. It’s also common for them to use a mix of APIs and web services to integrate the apps and microservices services that comprise them.
A microservices-based application architecture breaks a traditional monolithic application into its component functions. Rather than programming all application functions into a single piece of source code – as a monolith does – the microservices architecture isolates each function as a small, autonomously-running application, i.e., a microservice, which it typically runs in a containerized environment.
A group of microservices that make up a microservices-based application usually interconnect with each other through APIs (Application Programming Interfaces). When developing a microservices-based application like this, developers may use an API gateway – like DreamFactory – which offers an easy way to manage access to and establish integrations with the microservices that comprise the application.
APIs are the preferred method for connecting microservices because APIs support the widest variety of message formats (such as XML, XML-RPC, JSON, etc.) and the widest variety of message protocols (such as HTTP, HTTPS, MQTT, REST, and SOAP).
As we’ll discuss in the next section, developers can also connect microservices apps via “web services” to form a web services application architecture.
For a more detailed overview of how microservices work, please read our guides “What Are Microservices?”
Instead of carrying out a specific function on behalf of a larger application, – web services provide a standardized, web-based interface that makes the services of an application available to other applications on the internet.
W3.org nicely sums up the role of web services:
A web service is a software system designed to support interoperable machine-to-machine interaction over a network. It has an interface described in a machine-processable format (specifically WSDL). Other systems interact with the web service in a manner prescribed by its description using SOAP messages, typically conveyed using HTTP with an XML serialization in conjunction with other web-related standards.
Since web services allow diverse apps to connect and interact with each other, they are more like the glue that developers use to connect individual apps and build a web services application architecture. In fact, web services are APIs – or rather, one of the many representations of APIs. Artjoker Blog explains this distinction:
[A web service] is only one of the many API representations that use HTTP protocol for connection with third-party software solutions (for fairness’ sake, we’ll note that in rare cases, this connection is established via the other transport protocols like SMTP).
Another way of seeing web services is to view them as an “HTTP wrapper” around an API. This HTTP wrapper presents different services – that belong to a specific application – through a web interface, so other applications or microservices can interact with those services, even when the connecting systems are written in different programming languages and running on different OS platforms.
In this way a web service functions as a bridge – regardless of whether the connection is cloud-to-cloud, server-to-server, server-to-premises, cloud-to-premises, or client-to-server. This makes web services particularly valuable for enterprises that want to connect diverse software components running in different locations.
There are some however understandable obstacles you’ll need to keep in mind when using web services:
Fortunately an advanced iPaaS solution like DreamFactory can quickly overcome this lack of connection flexibility by converting messages from one format/protocol to another.
Here’s a quick overview of how a SOAP-based web service works to establish integrations between a third-party client and the application it offers services for:
Let’s look at the similarities and differences of microservices and web services from several different angles:
On the topic of “service specificity,” a microservice carries out a very specific service or task. For example, the Facebook Messenger platform includes a specific microservice that handles file attachments. You can access this specific functionality by using Facebook’s Attachment Upload API.
In contrast, a web service can offer one or or a multitude of services from a single application. This allows a web services architecture to organize access to the different services provided by an application. For an ecommerce application one web service could present customer-facing ordering and payment services, while another web service presents non-customer-facing inventory services. Even though access to these services is offered by separate web services, they couldl belong to the same application In this way, web services can help you manage and control access to the various services that belong to the same application.
With both microservices and web services application architectures, developers can easily add, remove, and upgrade the microservices and applications that form a larger application architecture. This modularity results in a more flexible, agile architecture because upgrades are faster, cheaper, and easier to achieve without disrupting the entire application.
With microservices, the APIs that connect them offer greater flexibility because they support both HTTP and HTTPS, and they can establish connections between dissimilar message formats and protocols.
Conversely, web services do not support HTTPS and the connected components must share the same message format and protocol. That being said, an iPaaS like DreamFactory can easily overcome the message format and protocol requirements of a web service connection.
Microservices often run in containers. Since multiple containers can run on the same operating system kernel, this reduces costs by requiring fewer operating system licenses to run the various microservices that comprise a larger app architecture. Also, the universal connective capacity of APIs means that developers save time and money when establishing microservices API connections – as they can forego the labor required to build a hand-coded, point-to-point connection. Since web services are an HTTP-based presentation of APIs, they also forego the time and expenses of hand-coded, point-to-point integrations. Finally, the pluggable nature of both microservices and web services architectures makes upgrades faster, simpler, and more cost-effective to achieve.
In microservices and web services architectures, the failure of one microservice or application is less likely to result in a cascade failure that affects the rest of the ecosystem. In both cases, developers can implement a circuit breaker design pattern to detect service failures and prevent them from disrupting other microservices or applications connected to the system.
Developers can create both microservices or web services architecture by connecting applications running on any platform written in virtually any programming language. This gives developers the freedom to choose the most suitable languages and platforms for the different microservices, apps, and web apps that comprise an architecture. It’s also easy for them to establish premises-to-premises, premises-to-cloud, and cloud-to-cloud integrations.
Microservices and web apps both allow for smaller, more focused, and easier-to-manage development teams. Managers can assign ownership of each web service or microservice to a small development team, allowing teams to work more independently and granularly on perfecting a single aspect of the application – without the fear of coding conflicts with other systems.
A difference to note is that web services development teams must stay on the same page regarding the common messaging formats and protocols shared across the web service integration.
If you’re developing a modern application architecture – or managing a large enterprise IT infrastructure – there’s a good chance you’ll need to integrate a mix of microservices and monolithic applications, and a mix of web services and APIs connect these diverse systems. While it’s true that microservices and API connections are getting the most attention these days, there are some situations when web services are better for connecting applications:
After reading this guide, you should have a better idea of what microservices and web services are — and how microservices and web services based applications are different. You should also be able to recognize the situations when web service connections offer a better solution than APIs.
If you’re in the process of developing a new application or IT infrastructure, the DreamFactory iPaaS can blow through your integration bottlenecks. As an advanced API gateway and web services connection solution, DreamFactory can automatically convert XML to JSON and SOAP to REST for web services integrations. Moreover, the platform features a point-and-click interface to instantly generate REST API for any system you want to connect.
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