In the early days of web application development, monolithic frontends and backends were perfectly fine. But the emergence of the cloud has changed expectations. Developers want to build applications that exchange information with APIs (Application Programming Interfaces). Business owners want faster development times. End users expect zero downtime. This new paradigm enabled the rise of service-oriented architecture (SOA) and, along with it, microservices and web services.
At first glance, microservices and web services seem very similar, and it may be hard to tell the difference between them. They both fall under the category of API representation tools. That is, they are both ways to deliver and share information via APIs. It’s common to find applications that use both microservices and web services, but they serve different needs. The first thing to understand is that microservices and web services deal with different concepts in modern application design.
At a high level, the differences are:
- A microservice is a small, independent application that performs a highly focused service within a larger application. Each microservice is a modular, unique process that can be developed and deployed independently.
- A web service is an internet-based interface that makes the “services” of an application available to other applications running on different platforms.
The main difference between the two is that a web service requires a network to function. As the name implies, web services operate on the World Wide Web, providing a service to other applications running on the internet. On the other hand, microservices operate within a single application, providing services within that app’s framework.
Microservices are one of the most popular concepts in application development today, and as such, it seems they get a lot more attention than web services. Businesses enjoy the flexibility of microservices in application development, as they allow separate teams to work on different parts of an application in a modular fashion.
In practice, however, both microservices and web services are important concepts in services-oriented application architectures. Understanding how both fit into the bigger picture of modern app design is essential.
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Microservices vs. Web Services: An Overview
Some basic definitions of microservices and web services are:
- Microservice: A small, autonomous application that performs a specific service for a larger application architecture.
- Web service: A strategy to make the services of one application available to other applications via a web interface.
Looking at those definitions, the functions of microservices and web services can look the same. That’s because web services can be seen as microservices in and of themselves. But they’re microservices that strictly function on the web and other internet services.
However, microservices and web services are not synonymous, and the biggest difference is in how they build application architectures. Here’s a look at their respective architectural styles:
- Microservices application architecture: A modular, services-oriented application architecture comprised of loosely connected, independently running microservices. These microservices usually offer APIs (Application Programming Interfaces), so other microservices and apps can integrate with them.
- Web services application architecture: A modular, services-oriented application architecture where the applications that comprise the architecture connect via web services. Developers can use web services to connect microservices, monolithic applications, and more to form a larger application.
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 combination of APIs and web services to integrate the apps and microservices services that comprise them.
Microservices Application Architecture
The microservices 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 small, autonomously-running applications. These small and independent applications are microservices, which typically run in a containerized environment.
This design philosophy is what is known as componentization. The major advantage of componentization is that all services of an application be deployed independently. In traditional monolithic development, all of an application’s functions and services rely on a single large code base. Changes to the code can affect all parts of the application. But when services are developed as components, they are independent of each other and can be upgraded or replaced as needed without affecting the application as a whole.
A group of microservices that make up a microservices-based application usually interconnect with each other through APIs. When developing a microservices-based application like this, developers can use an API gateway – like DreamFactory – which offers an easy way to manage access to, and establish integrations with, the application’s microservices.
API Connections for Microservices Are Flexible
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).
This flexibility in formats and protocols makes microservices and the microservices application architecture popular among developers.
As we’ll discuss in the next section, developers can also connect microservices apps via web services to form a web services application architecture.
Before we get into that, if you’d like a more detailed overview of how microservices work, please read our guide “What Are Microservices?”
Web Services Application Architecture
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 available to other applications on the internet.
W3.org sums up the role of web services like this:
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 various 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. Web services are often equated with APIs as if the two are one and the same. A better way to look at it is that web services are 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 understanding web services is to view them as an “HTTP wrapper” around an API. This wrapper lets applications present their services through a web interface so other applications or microservices can interact with those services. Web services are popular because they allow this exchange of services and data, even when the connecting systems are written in different programming languages or running on different 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.
However, there are some conditions you’ll need to keep in mind when using web services:
- The applications and web services that comprise a web services application architecture need to share the same message format (typically XML or JSON).
- The applications and web services must also share the same message protocol (HTTP, MQTT, REST, SOAP, etc.).
Fortunately, an advanced iPaaS solution like DreamFactory can quickly overcome this lack of connection flexibility by converting messages from one format/protocol to another.
With that in mind, let’s take a look at how web services work.
How Web Services Work
Here’s a quick overview of how a SOAP-based web service works to establish integrations between the application it offers services for and a third-party client:
- The web service is a web-based interface that allows clients (or third-party apps) to access an application’s data or services.
- The client calls the web service by sending a series of RPC (Remote Procedure Call) requests to the server that hosts the web service. The advantage of an RPC request is that it doesn’t matter what language the client and the application are written in. For example, if the client is written in .Net and the application in Java, both can still communicate through the web service.
- The web service responds to the RPC by returning XML data to the client. XML is a standard messaging platform that most programming languages understand.
- When transmitting the XML document to the client, the web service uses the messaging protocol SOAP (Simple Object Access Protocol) and sends the data through HTTP.
Comparing Microservices and Web Services
Let’s look at the similarities and differences between microservices and web services from several different angles:
Service Specificity
A microservice carries out a highly specific service or task. This is known as “service specificity.”
The Facebook Messenger platform includes a microservice that handles file attachments. You can access this particular functionality by using Facebook’s Attachment Upload API. As the microservice exists specifically to handle the process of uploading and attaching files, this is an example of a microservice with service specificity that many of us are familiar with.
In contrast, a web service can offer one or many services from a single application. This allows a web services architecture to organize access to the different services provided by an application.
For an e-commerce application, one web service could present customer-facing ordering and payment services, while another web service presents non-customer-facing inventory services. Even though separate web services offer access to these services, they belong to the same application.
This is an example of how web services can help you manage and control access to the various services that belong to the same application and are not bound by service specificity.
Pluggability
With architectures built on both microservices and web services, 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 to ensure a successful exchange over web service connections.
Cost-Effectiveness
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. This is because 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.
Resilience
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. With both architectures, 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.
Language and Platform Agnostic
Developers can create both microservices or web services architecture by connecting applications running on any platform written in virtually any programming language. This allows developers 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.
Smaller Development Teams
Microservices and web apps 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. This allows teams to work independently and with granularity, perfecting a single aspect of the application without the fear of coding conflicts with other systems.
However, it should be noted that web services development teams must stay on the same page concerning the common messaging formats and protocols shared across web service integrations.
When Are Web Services Appropriate?
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. A combination 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:
- When organizing access to different services offered by a single monolithic application, a web service lets you create a service-oriented architecture that makes specific services from the monolith available through different web services. This helps you manage and organize access to specific aspects of the same monolithic application.
- Since each microservice has its own connection to a corresponding database, microservices architectures can be taxing on system resources when all of the microservices are constantly making calls to their databases. Conversely, a monolithic application requires fewer database connections and calls, which can save on system resources. With web service connections, developers can still benefit from a service-oriented architecture while simultaneously avoiding system slowdowns caused by too many database calls.
In general, web services work well for complex projects that communicate information over a network. They are also a good choice for bigger enterprise application environments because they can integrate between many other applications and platforms that might otherwise not have interoperability. Of course, business and project requirements should always be the determining factor when choosing the ideal architecture for any software project.
Build Connection for Web Services and Microservices the Easy Way
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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Try DreamFactory 4.12.0
DreamFactory 4.12.0 has been released! Our latest version has two additional Google connectors, AlloyDB and BigQuery. AlloyDB is a fully-managed PostgreSQL-compatible database service that Google claims to be up to four times faster than PostgreSQL under the same workloads. BigQuery is a serverless data warehouse enabling scalable analysis, with the ability to analyze data in the billions of rows. And with this update, we’ve taken the time to update our Docker images. The Docker version now sports Ubuntu 20 as its OS. This latest release incorporates all the other improvements in the DreamFactory 4.x line. We’re putting a lot of focus on the user experience, especially in the process of API generation. The most popular database connectors (MySQL, MariaDB, PostgreSQL, MS SQL Server, and Oracle) have long included a lengthy list of options, and it hasn’t been obvious which are required and which are optional. To remedy this, we’ve broken the service creation form into three sections: Basic, Caching, and Optional Advanced Settings. Additionally, because the Services tab is the natural first tab new users should be clicking on after logging in, we’ve moved the tab to the second position in the navigational bar directly following the Home tab. Upcoming versions will see a stream of additional UX improvements intended to guide new users through the API generation process. If you haven’t tried DreamFactory before, now is the time. Sign up for a hosted trial of DreamFactory now!
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